While working on the reactivity it's very helpful to be able to log a
snapshot of the effect tree. This PR augments the existing
`log_effect_tree` helper by marking unreachable-but-dirty effects, like
so:
<img width="333" height="415" alt="image"
src="https://github.com/user-attachments/assets/2c7501f7-b845-4271-b534-3a8be0ff62ee"
/>
(I had thought `log_inconsistent_branches` was designed to help with
this but it didn't work for me. Do we need both? cc @dummdidumm)
---------
Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com>
I cannot tell you how many times I have temporarily added this code to
make it easier to debug some async stuff. I am extremely bored of doing
so. I'm just going to add it to `main` to save myself the annoyance. We
can remove it once everything async is stable
## Summary
- The `SvelteURL` `search` setter stored the raw input `value` instead
of `super.search`, unlike every other setter in the class
- This caused `url.search` to return incorrect values when the URL API
normalizes the input (e.g. adding the `?` prefix, or stripping a lone
`?`)
- For example: `url.search = 'foo=bar'` would return `'foo=bar'` instead
of `'?foo=bar'`
## Test plan
- [x] Added `url.search normalizes value` test covering:
- Setting search without `?` prefix
- Setting search with `?` prefix (existing behavior)
- Setting search to lone `?` (normalized to `""`)
- [x] All existing reactivity tests pass (46/46)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
## Summary
Two optimizations to the compiler's analysis phase:
- **Cache `ignore_stack` snapshots instead of `structuredClone` on every
node.** The universal `_` visitor in the analysis walk runs on every AST
node and calls `structuredClone(ignore_stack)` each time. In practice,
`svelte-ignore` comments are rare (0–5 per component), so 99%+ of nodes
deep-clone an unchanged stack. This adds a copy-on-write cache that only
re-creates the snapshot when `push_ignore`/`pop_ignore` actually change
the stack.
- **Walk the CSS stylesheet once instead of once per element.**
`prune()` was called in a loop for each element, each time doing a full
`walk()` of the stylesheet AST. This restructures the loop so the
stylesheet is walked once, and the element iteration happens inside the
`ComplexSelector` visitor.
## Benchmarks
Compiled each component 500 times (after 50 warmup iterations),
measuring average time per `compile()` call:
| Component | Before | After | Speedup |
|---|---|---|---|
| `has` (80+ CSS selectors, 12 elements) | 3.405 ms | 2.680 ms | **21%
faster** |
| `siblings-combinator-each-nested` (65 CSS rules, 15 elements) | 2.034
ms | 1.575 ms | **23% faster** |
| synthetic (100 CSS rules, 50 elements) | 10.099 ms | 4.564 ms | **55%
faster** |
The CSS pruning optimization scales with `elements × CSS rules` — the
more elements a component has, the bigger the win since we go from N
stylesheet walks down to 1. The `structuredClone` fix helps every
component regardless of CSS, eliminating ~500–2000 deep clones per
compile (one per AST node) and replacing them with 0–5 (one per
`svelte-ignore` comment).
For typical real-world components with 10–20 elements and some CSS,
expect roughly **20–30% faster compilation** in the analysis phase.
## Test plan
- [x] Full test suite passes (7329 tests, 0 failures)
- [x] CSS pruning tests pass (selector matching, scoping, unused rule
detection)
- [x] `svelte-ignore` behavior unchanged (snapshot is consumed read-only
via `.has()`/`.some()`)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Fixes events not being stripped on svg, mathml and custom elements.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Closes#17821
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
## Summary
`SvelteMap` had two bugs related to how it checked for key existence
internally:
### 1. `has()` and `get()` returned wrong results for keys with
`undefined` values
Both methods used `super.get(key) !== undefined` to determine if a key
existed before creating a per-key reactive source. This fails for keys
whose value is legitimately `undefined`, causing:
- `has(key)` to return `false` for existing keys with `undefined` values
- `get(key)` to skip creating a per-key source and fall back to tracking
`version`, resulting in over-notification
**Fix:** Replace `super.get(key) !== undefined` with `super.has(key)` in
both `has()` and `get()`, matching the pattern already used in
`SvelteSet`.
### 2. `delete()` skipped reactive updates when a key had no per-key
source
The `size` and `version` reactive updates were inside the `if (s !==
undefined)` block, meaning they only fired when a per-key source existed
(i.e., someone had previously called `has()` or `get()` on that specific
key). If a key was added via the constructor or `set()` but never
individually read, deleting it would not trigger reactive updates for
effects depending on `size` or iterators.
**Fix:** Move `set(this.#size, super.size)` and
`increment(this.#version)` to a separate `if (res)` block so they fire
whenever a key is actually deleted, regardless of whether a per-key
source existed.
### Before fix
```js
const map = new SvelteMap([['foo', undefined]]);
map.has('foo'); // false (should be true)
map.get('foo'); // undefined but tracks version instead of per-key source
```
### After fix
```js
const map = new SvelteMap([['foo', undefined]]);
map.has('foo'); // true
map.get('foo'); // undefined with correct per-key tracking
```
## Test plan
Tests are in `packages/svelte/src/reactivity/map.test.ts`:
- `map.has()` returns `true` for constructor-initialized keys with
`undefined` values
- `map.get()` returns `undefined` with proper per-key reactive tracking
- `map.delete()` triggers `has()`/`get()` reactivity for
undefined-valued keys
- `map.set(key, undefined)` followed by `has()`/`get()` works correctly
- `map.delete()` triggers `size` reactivity for keys that were never
individually read (no per-key source)
- All existing tests pass unchanged
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
tiny fix — just realised we're calling `this.apply()` (via
`this.activate()`) unnecessarily, since it will happen again immediately
after in `flush_effects`
another extraction from #17805. I always felt bad about
`this.process([])`, and this PR replaces it with the steps that actually
occur — even though this is arguably duplicative, I find it much easier
to understand.
It also allows us to avoid activating batches with no queued effects,
thanks to the change in #17809. This saves us a bit of work in a
not-that-uncommon case.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [ ] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
follow-up to #17808. This makes it a bit more explicit _why_ we do
certain things in `create_effect`, and gets rid of a redundant parameter
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [ ] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This extracts part of #17805 into its own PR that can be merged
independently.
Today, if a (non-render) effect is created during traversal (e.g. an
`{#if condition}` block becomes true, and an `$effect` is created
somewhere inside it) then it goes through `schedule_effect`, ultimately
causing the loop in `flush_effects` to run again. This is wasteful. We
can instead push to an array — `collected_effects` — which is flushed
following the first traversal.
By using `collected_effects !== null` as a proxy for 'is traversing', we
can also simplify the bail-out logic inside `schedule_effect` and make
it work in more cases. Bailing out means that in the case that a signal
is written to during traversal (which is the case for `each` blocks, for
example), we can avoid triggering another turn of the loop because we
know that the affected effects are about to be discovered as a result of
the ongoing traversal.
All this brings us slightly closer to the intermediate goal in #17805 of
ensuring that scheduled effects always belong to a specific batch.
No test for this because it shouldn't have any user-observable impact,
though I've added a changeset out of an abundance of caution.
Another small tweak extracted from #17805, just to make that diff a bit
more legible.
By passing the `batch` to the branch commit callback, we don't need to
rely on the value of `current_batch` being the same as the batch
currently being processed. That gives us more control over the order of
operations — for example we can null out `current_batch` _before_
committing branches, which is important (at present, if a state change
occurs while those branches are being committed, it will belong to the
current batch, but the resulting effects will happen in the context of a
_new_ batch, which is something we need to avoid for the sake of
#17805).
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.53.5
### Patch Changes
- fix: escape `innerText` and `textContent` bindings of
`contenteditable`
([`0df5abcae223058ceb95491470372065fb87951d`](0df5abcae2))
- fix: sanitize `transformError` values prior to embedding in HTML
comments
([`0298e979371bb583855c9810db79a70a551d22b9`](0298e97937))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
We never cleared the list of (maybe)dirty_effects on the assumption that
once a batch has run them it's complete. But that's not the case when a
boundary has a pending snippet, in which case the pending snippet shows
up, so `blocking_pending` is already 0 and effects are flushed. That can
lead to effects being run unnecessarily, even leading to infinite loops.
So we clear them. This is safe because any additional effects would
either be scheduled by the boundary (which keeps track of the offscreen
effects created while the pending snippet is shown, and schedules them
once the pending snippet goes away) or by unskipping skipped branches
(which reschedules the effects inside it)
Fixes#17717
After creating the test I noticed it fails when run together with other
tests, but not alone, which lead me to discover that we're missing an
`unset_context`. I also added clearing of `#skipped_branches` just to be
safe.
Use separate scopes for function declarations/expressions and function
bodies. This prevents variable declarations from leaking into default
parameter initialization expressions.
Closes#17785.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.53.3
### Patch Changes
- fix: render `:catch` of `#await` block with correct key
([#17769](https://github.com/sveltejs/svelte/pull/17769))
- chore: pin aria-query@5.3.1
([#17772](https://github.com/sveltejs/svelte/pull/17772))
- fix: make string coercion consistent to `toString`
([#17774](https://github.com/sveltejs/svelte/pull/17774))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Closes#17758
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
The only change between 5.3.1 and 5.3.2 is
2106d5e872
to support versions of Node before 4, with the cost of a minuscule but
pointless performance hit. This is a pretty stable library, and there
have been no further changes in the ensuing year and a half, so it seems
pretty safe to pin to the previous version.
### Before submitting the PR, please make sure you do the following
- [ ] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [ ] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.53.2
### Patch Changes
- fix: update expressions on server deriveds
([#17767](https://github.com/sveltejs/svelte/pull/17767))
- fix: further obfuscate `node:crypto` import from overzealous static
analysis ([#17763](https://github.com/sveltejs/svelte/pull/17763))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.53.1
### Patch Changes
- fix: handle shadowed function names correctly
([#17753](https://github.com/sveltejs/svelte/pull/17753))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Fixes#17750 (though the change that causes the issue only surfaced this
more general bug)
We were not adding the correct scope to function ids. Instead it was
part of the function body/params scope, which leads to bugs when the
function name is shadowed within the function.
Alternative to #17188. I prefer this syntax, it's lighter and feels much
more natural to me. For me it's less about commenting things _out_ than
about just, well... commenting — I frequently want to do this sort of
thing:
```svelte
<button
// when the user clicks the button, the thing should happen
onclick={doTheThing}
>click me</button>
```
One difference between this and #17188 is that this doesn't add a node
to the AST, just like comments in CSS/JS. Haven't decided if that's
desirable or not. I think it's more correct (it's an AST, not a CST;
HTML comments are different insofar as they _can_ represent 'real'
nodes) but it might be less convenient when (for example)
pretty-printing.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
This makes error boundaries run on the server if a new `onerror` handler
is passed to `render`. `onerror` can either synchronously or
asynchronously return a value. It should be a sanitized
JSON.stringify-able value so that it can be passed to the client for
hydration via a comment. `mount/hydrate` also get the `onerror`
property.
If no `onerror` is passed to `render` it will just throw just like
before, hence this is backwards compatible.
This work is important for SvelteKit to allow `+error.svelte` to make
use of them and in general to make boundaries properly work during SSR
(also see https://github.com/sveltejs/kit/issues/14398).
closes#15370
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
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- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
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---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Fixes#17726
The problem was that the head effect had no "keep me around"-flag, which
it needs because its children are not guaranteed to be present
immediately - as shown in the related issue, where the child effect is
only created once async work has completed.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
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- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
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Small tweak: except for `{#await ...}` blocks, which are a bit of an
anomaly, I'm pretty sure we _always_ want to deactivate the current
batch when unsetting context, otherwise it could incorrectly pick up
unrelated state changes. There might even be some subtle bugs lurking in
the system at present because we _don't_ always do this
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
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- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.52.0
### Minor Changes
- feat: support TrustedHTML in `{@html}` expressions
([#17701](https://github.com/sveltejs/svelte/pull/17701))
### Patch Changes
- fix: repair dynamic component truthy/falsy hydration mismatches
([#17737](https://github.com/sveltejs/svelte/pull/17737))
- fix: re-run non-render-bound deriveds on the server
([#17674](https://github.com/sveltejs/svelte/pull/17674))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
I tried to bring #14977 up-to-date but it's slipped too far. Also, I
wanted to try a slightly different approach.
In this PR, deriveds are memoized if they're created during render — in
other words if you have something like this...
```svelte
<script>
let thing = $derived(expensivelyComputeThing());
</script>
```
...`thing` will only be computed once. This seems correct since the
inputs should never change during render.
For deriveds created _outside_ render, we re-run the derived each time
it is accessed, which fixes#14954. This way, there's still _some_
overhead compared to how deriveds work in the browser (where they only
recompute when their dependencies have changed), but only in the rare
places where it is necessary.
There is one wrinkle: writable deriveds. On `main` these are just
regular old variables, which means they can be written to during render.
This PR currently preserves that behaviour, but I'm not sure it's
desirable. It prevents the values of non-render-bound deriveds from ever
updating, and makes no sense in the context of render-bound deriveds
since they shouldn't be changing during render _anyway_. So my
preference would be to disallow writes to deriveds on the server, but
I'm not sure if we would need to consider that a breaking change.
Draft because of that question, and also because I think we might be
able to tidy up some stuff around class fields.
- [x] figure out if we can delete some existing code around derived
class fields
- [x] figure out what to do about writable deriveds
- [x] add a test
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
Follow-up to #16271.
## Summary
- Allow `{@html}` blocks to accept `TrustedHTML` objects (from
TrustedTypes policies) without coercing them to strings
- This enables usage like `{@html myPolicy.createHTML(someHTML)}`
- Works in regular HTML, SVG, and MathML contexts
## Changes
- **`html.js`**: Instead of calling `create_fragment_from_html`, create
the wrapper element directly (`<template>`, `<svg>`, or `<math>`
depending on context) and assign the value to `innerHTML`. This
preserves `TrustedHTML` objects.
- **`reconciler.js`**: Removed the `trusted` parameter from
`create_fragment_from_html` since it's no longer used by `{@html}` and
all remaining callers want trusted HTML.
- **`template.js`** and **`snippet.js`**: Removed the second argument
from `create_fragment_from_html` calls.
## Notes
No tests added because JSDOM doesn't implement TrustedTypes.
Fixes#17735
Use the if/else hydration markers to know what "branch" (component or no
component) was rendered, and repair if differing.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.51.5
### Patch Changes
- fix: check to make sure `svelte:element` tags are valid during SSR
([`73098bb26c6f06e7fd1b0746d817d2c5ee90755f`](73098bb26c))
- fix: misc option escaping and backwards compatibility
([#17741](https://github.com/sveltejs/svelte/pull/17741))
- fix: strip event handlers during SSR
([`a0c7f289156e9fafaeaf5ca14af6c06fe9b9eae5`](a0c7f28915))
- fix: replace usage of `for in` with `for of Object.keys`
([`f89c7ddd7eebaa1ef3cc540400bec2c9140b330c`](f89c7ddd7e))
- fix: always escape option body in SSR
([`f7c80da18c215e3727c2a611b0b8744cc6e504c5`](f7c80da18c))
- chore: upgrade `devalue`
([#17739](https://github.com/sveltejs/svelte/pull/17739))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
### Before submitting the PR, please make sure you do the following
- [ ] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [ ] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [ ] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [ ] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [ ] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
### Before submitting the PR, please make sure you do the following
- [ ] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [ ] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [ ] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [ ] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [ ] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.51.4
### Patch Changes
- chore: proactively defer effects in pending boundary
([#17734](https://github.com/sveltejs/svelte/pull/17734))
- fix: detect and error on non-idempotent each block keys in dev mode
([#17732](https://github.com/sveltejs/svelte/pull/17732))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Currently, (render/template) effects inside pending boundaries are
deferred, but in an indirect manner: first we schedule them, then we
`flush` the current batch, and in the course of traversing the effect
tree we find any dirty effects and defer them at the level of the
topmost pending boundary.
This doesn't really make sense — we can just skip to the end state and
skip the scheduling/traversal, since the effects don't become relevant
until the boundary resolves.
This PR implements that. It is a stepping stone towards a larger
refactor, in which scheduling becomes batch-centric and lazier. While it
shouldn't change any observable behaviour, I've added a changeset out of
an abundance of caution.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
## Summary
Fixes#17721
In dev mode, detect when a keyed each block has a key function that
returns different values when called multiple times for the same item
(non-idempotent). This catches the common mistake of using array
literals like `[thing.group, thing.id]` as keys, which creates a new
array object each time and will never match by reference.
- Adds new `each_key_volatile` error with helpful message explaining the
issue
- Checks key idempotency in the each block loop during dev mode
- Provides a clear error instead of the cryptic "Cannot read properties
of undefined" that occurred previously
---------
Co-authored-by: 7nik <kifiranet@gmail.com>
We have a bunch of repeated logic around incrementing/decrementing
pending states. This DRYs it out to unblock some forthcoming changes
around scheduling
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.51.3
### Patch Changes
- fix: prevent event delegation logic conflicting between svelte
instances ([#17728](https://github.com/sveltejs/svelte/pull/17728))
- fix: treat CSS attribute selectors as case-insensitive for HTML
enumerated attributes
([#17712](https://github.com/sveltejs/svelte/pull/17712))
- fix: locate Rollup annontaion friendly to JS downgraders
([#17724](https://github.com/sveltejs/svelte/pull/17724))
- fix: run effects in pending snippets
([#17719](https://github.com/sveltejs/svelte/pull/17719))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Fixes https://github.com/sveltejs/svelte.dev/issues/1793. There are
actually two fixes here, and either is sufficient to fix the playground,
but they are complementary. First, we only add the delegated event
handler _after_ the component has successfully mounted, otherwise it
will never get cleaned up if an error occurs during mount.
Second, instead of storing data on `event.__root` (which leaks between
instances), we reuse the existing `event_symbol` to provide the
necessary encapsulation. (I'll be honest I don't totally understand what
this property is for anyway and can't be bothered to figure it out right
now, but I'm sure it's important.)
No test because I'm not really sure how you _would_ test this; it
requires a fairly esoteric setup.
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Fixes#17207
CSS attribute selectors for HTML enumerated attributes (like `method`,
`type`, `dir`, etc.) are supposed to match case-insensitively per the
HTML spec. Browsers handle this correctly — `form[method="get"]` matches
`<form method="GET">`. But Svelte's CSS pruning was doing a strict
case-sensitive comparison, which meant:
1. The selector got incorrectly flagged as unused (no
`css_unused_selector` warning was shown when spreads were involved, but
the selector was still pruned)
2. The scoping class wasn't applied to the matching element
3. Styles silently disappeared in production builds
The fix adds a set of known HTML attributes with case-insensitive
enumerated values (sourced from the HTML spec) and uses it during CSS
attribute selector matching. The explicit CSS `s` flag still overrides
this behavior, as expected.
### Before
```svelte
<form method="GET">
<h1>Hello</h1>
</form>
<style>
form[method="get"] h1 { color: red; }
/* ^ incorrectly pruned, <h1> not styled */
</style>
```
### After
The selector correctly matches and styles are applied.
### Test plan
- Added `attribute-selector-html-case-insensitive` CSS test covering
`form[method]` and `input[type]` cases
- All 179 existing CSS tests pass
- Verified the existing `attribute-selector-case-sensitive` test (using
`s` flag) still works correctly
- Compiler error tests and validator tests all pass
---------
Co-authored-by: Rich Harris <hello@rich-harris.dev>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Boundaries are buggy: if the `pending` snippet contains state, changes
to that state [won't cause
updates](https://svelte.dev/playground/hello-world?version=5.51.2#H4sIAAAAAAAAE22SQW-DMAyF_0qUTSpoE92uFJh223Hate0hJWaNliZRYsoqxH9fQtJW6noD-33Pz4aRKnYAWtIPkFKTQVvJSQZcIPCcPtNOSHC0XI8UTyboQsHXE_VuTOGOIDHUdszBvXqrFYJCb0Mr11phsNmoDUpAYsFpeQTrSE3W25Uv-0bXqxaFVsT0bp8dmewhJ2PobNB7OSQcOrAWuKc-rT4IB8UgcP91dsvyVZRf_IvZK8tJ3VzoInXTiCuDvVVXlYkT5u50k9DtRYfZJd11XGq8FSlKAsPOre4V-uSPDhlC9hIE1fJ6GFXtekRvrlUrRftTjzF25J5q8jrN9xOqtXDwhw14RO7jc5bIzI-3-vihyp3358yeZmFlmpENTGD8CIu0GV_kU7U0TdxmfHBKGON3MqC4UN9ZPsVDBHzOe1bjuEzaad7230j_nyD8Ii3R9jBt_RsTchCK07Jj0sH0B6hNF6aqAgAA):
```svelte
<script>
let resolvers = [];
function push(value) {
const deferred = Promise.withResolvers();
resolvers.push(() => deferred.resolve(value));
return deferred.promise;
}
function shift() {
resolvers.shift()?.();
}
let count = $state(0);
</script>
<button onclick={() => count += 1}>
increment
</button>
<button onclick={shift}>
shift
</button>
<svelte:boundary>
<p>{await push('resolved')}</p>
{#snippet pending()}
<p>{count}</p>
{/snippet}
</svelte:boundary>
```
The issue is that the boundary's `this.#effect` has the
`BOUNDARY_EFFECT` flag, and `this.#pending_effect` is a child thereof.
Instead, `this.#main_effect` should have the flag. (It turns out
`this.#failed_effect` _also_ needs the flag, because errors that occur
in a `failed` snippet cause the boundary to re-render in its `failed`
state, which I found somewhat confusing to be honest. Probably the right
choice though.)
I was able to simplify the code a bit, too.
~~(Actually now that I think about it do we need `this.#effect` at all?
Will check.)~~
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Closes#17722
Looks like after downgrading `?.`, `/* @__PURE__ */` may happen in an
invalid location.
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.51.2
### Patch Changes
- fix: take async into consideration for dev delegated handlers
([#17710](https://github.com/sveltejs/svelte/pull/17710))
- fix: emit state_referenced_locally warning for non-destructured props
([#17708](https://github.com/sveltejs/svelte/pull/17708))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Non-destructured `$props()` access in runes mode silently skipped the
`state_referenced_locally` warning, leading to missed guidance when
users read `props` via identifiers or member expressions.
- **Analyzer behavior**
- Include `rest_prop` bindings in `state_referenced_locally` detection
so reads of `$props()` identifiers warn consistently with destructured
props.
- **Validation coverage**
- Add a validator fixture for `$props()` identifiers and update the
`props-identifier` snapshot expectations to capture the new warnings.
Example:
```svelte
<script>
const props = $props();
const { model } = props; // now warns
const value = props.model.value; // now warns
</script>
```
<!-- START COPILOT ORIGINAL PROMPT -->
<details>
<summary>Original prompt</summary>
>
> ----
>
> *This section details on the original issue you should resolve*
>
> <issue_title>False negative for `state_referenced_locally` warning on
not destructured `$props` access?</issue_title>
> <issue_description>### Describe the bug
>
> I was looking for a workaround for sveltejs/svelte#17669 and thought
of not destructuring the `$props` directly; to my surprise there were no
warnings at all.
>
>
> ### Reproduction
>
> ```js
> const props = $props();
> const { model } = props; // missing warning
>
> const value = props.model.value; // missing warning
> ```
>
>
[Playground](https://svelte.dev/playground/untitled?version=5.50.2#H4sIAAAAAAAACn2QT4vCQAzFv0oIe1CQ9l51YY97lj1tPYxtXAam6TAT_1H63U0HUax1j3nvJeT3OmTTEBb4w2LFUY0L3FtHEYvfDuXiB28QVL8lv7zP4pGcDNrORJrSq5aFWPQMrmIVrJfPkktROQp00LQ1OehhDR8-tD7O5ku174GjcQdSM8WyNC0hz4HOniqhGk4msOW_klf54zrPNkTwzVUbgsZuz8z1G6GzYCHhQP3iDdV47Zltwv2XMEGN6Cbgk5vIGhujAj3AXstI4WxcycvivZFn7q1OxrqT5RqLvXGR-itXywVk_AEAAA)
>
> ### Logs
>
> ```shell
>
> ```
>
> ### System Info
>
> ```shell
> REPL - Svelte v.5.50.2
> ```
>
> ### Severity
>
> annoyance</issue_description>
>
> ## Comments on the Issue (you are @copilot in this section)
>
> <comments>
> </comments>
>
</details>
<!-- START COPILOT CODING AGENT SUFFIX -->
- Fixessveltejs/svelte#17685
<!-- START COPILOT CODING AGENT TIPS -->
---
💡 You can make Copilot smarter by setting up custom instructions,
customizing its development environment and configuring Model Context
Protocol (MCP) servers. Learn more [Copilot coding agent
tips](https://gh.io/copilot-coding-agent-tips) in the docs.
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Rich-Harris <1162160+Rich-Harris@users.noreply.github.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: Paolo Ricciuti <ricciutipaolo@gmail.com>
Closes#17709
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [x] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.51.1
### Patch Changes
- fix: don't crash on undefined `document.contentType`
([#17707](https://github.com/sveltejs/svelte/pull/17707))
- fix: use symbols for encapsulated event delegation
([#17703](https://github.com/sveltejs/svelte/pull/17703))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
This PR was opened by the [Changesets
release](https://github.com/changesets/action) GitHub action. When
you're ready to do a release, you can merge this and the packages will
be published to npm automatically. If you're not ready to do a release
yet, that's fine, whenever you add more changesets to main, this PR will
be updated.
# Releases
## svelte@5.51.0
### Minor Changes
- feat: Use `TrustedTypes` for HTML handling where supported
([#16271](https://github.com/sveltejs/svelte/pull/16271))
### Patch Changes
- fix: sanitize template-literal-special-characters in SSR attribute
values ([#17692](https://github.com/sveltejs/svelte/pull/17692))
- fix: follow-up formatting in `print()` — flush block-level elements
into separate sequences
([#17699](https://github.com/sveltejs/svelte/pull/17699))
- fix: preserve delegated event handlers as long as one or more root
components are using them
([#17695](https://github.com/sveltejs/svelte/pull/17695))
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Follow-up to #17319.
The `Fragment` visitor in `print()` only flushed sequences on
`RegularElement`, causing block-level elements (`Component`,
`SvelteHead`, `SvelteBoundary`, etc.) to be lumped into the same
sequence as adjacent nodes. This broke tools that programmatically
manipulate the AST (e.g.
[sveltejs/cli#915](https://github.com/sveltejs/cli/pull/915)).
The fix flushes before and after all block-level element types, ensuring
they get their own sequence and proper line separation.
### Before
```svelte
<svelte:head><title>Page Title</title></svelte:head><div>no space</div>
<Component /><Component />
<Component><span>child</span></Component><div>after component</div>
<svelte:boundary><div>boundary content</div></svelte:boundary><div>after boundary</div>
<!--comment--><div>after comment</div>
<div>before comment</div>
<!--comment-->
{#each items as item}
<div>{item}</div>
{/each}<div>after each</div>
{@render children()}<div>after render</div>
<div>before render</div>
{@render children()}
```
### After
```svelte
<svelte:head><title>Page Title</title></svelte:head>
<div>no space</div>
<Component />
<Component />
<Component><span>child</span></Component>
<div>after component</div>
<svelte:boundary><div>boundary content</div></svelte:boundary>
<div>after boundary</div>
<!--comment-->
<div>after comment</div>
<div>before comment</div>
<!--comment-->
{#each items as item}
<div>{item}</div>
{/each}
<div>after each</div>
{@render children()}
<div>after render</div>
<div>before render</div>
{@render children()}
```
### Before submitting the PR, please make sure you do the following
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
- [x] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
Fixes#17694
Not really sure how to add a failing test here.
The code was generated by Codex 5.3, but I cleaned it up and manually
reviewed it myself. Not sure if this is the best approach to solving the
issue, though. It does add some overhead with the extra maps.
---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: Rich Harris <hello@rich-harris.dev>
### Before submitting the PR, please make sure you do the following
Resolves https://github.com/sveltejs/svelte/issues/14438
Resolves https://github.com/sveltejs/svelte/issues/10826
This PR makes it possible to use Svelte on pages which require
`TrustedTypes` support via their CSP by wrapping assignments to
`innerHTML` in a `TrustedTypePolicy` called `svelte-trusted-html` if the
`TrustedTypes` API exists.
Servers can allowlist the policy by setting `require-trusted-types-for
'script'; trusted-types svelte-trusted-html` in their
`Content-Security-Policy` header.
- [x] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
https://github.com/sveltejs/rfcs
- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
solves.
- [ ] Ideally, include a test that fails without this PR but passes with
it.
- [x] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`).
### Tests and linting
Note: I haven't run the tests since I don't have `pnpm` setup properly.
I have tested that:
1. A project with a CSP fails with Tip of Tree Svelte
2. That project works when installing this revision of Svelte
3. The project (with this revision) works in Browsers with no
`TrustedTypes` support (i.e. Firefox, Safari)
- [ ] Run the tests with `pnpm test` and lint the project with `pnpm
lint`
My test project is here:
https://github.com/fallaciousreasoning/svelte-tt-test/blob/master/src/routes/%2Bpage.server.js
The only changes to the default project is adding the CSP in
`src/routes/page.server.js`
---------
Co-authored-by: 7nik <kfiiranet@gmail.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: Rich Harris <hello@rich-harris.dev>
Fixes a minor bug where HTML entities could be decoded into significant
characters in the template literal we output for SSR, leading to weird
effects. Not a security issue because it has to be literally written
into the svelte file you're compiling, but still wrong.
---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Fixes#16342.
Errors thrown inside `$effect` were previously treated as
subtree-creation errors when `EFFECT_RAN === 0`, which caused them to be
rethrown instead of propagating to the nearest `<svelte:boundary>`. As a
result, `$effect` errors bypassed boundaries and appeared as uncaught
runtime errors. This change ensures that errors originating from effects
(`EFFECT`) are routed through `invoke_error_boundary`, allowing them to
bubble up the effect tree and be handled correctly by the closest
boundary. Existing subtree-creation behavior for non-effect cases
remains unchanged.
---
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---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
It should be the last piece of XHTML compliance.
We missed fixing `mutltiple` and `selected` attributes on `<select>` and
`<option>`.
Also, it seems the test runtime-legacy/select-multiple-spread was
broken.
I just copied to runtime-xhtml and updated tests that fail when a
`nodeName` comparison is broken. For `<progress>` no test due to JSDOM
quirks (at least in the past), and for `<template>` and `<script>`
nothing got broken 🤔
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---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
This supersedes #16595, and fixes the issue by 'freezing' effects inside
deriveds when those deriveds are disconnected, and unfreezing them when
they reconnect. This is preferable to the current asymmetric behaviour
on `main` (in which effects are destroyed when the derived is
disconnected, and never recreated) and #16595, which causes the derived
itself to be re-evaluated.
### Before submitting the PR, please make sure you do the following
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follow-up to #17418. This replaces every occurrence of
`document.createElement` with a helper, `create_element`, that delegates
to `document.createElementNS`. This makes the code a tiny bit simpler
and in theory should allow Svelte to run on `text/xml` documents, though
I'm not ready to add a test suite to prevent regressions for something
so niche.
If we choose to merge this, I think we can safely close#17418 as all
the other points (around case sensitivity etc) have already been taken
care of AFAICT.
### Before submitting the PR, please make sure you do the following
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---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Tee Ming <chewteeming01@gmail.com>
Another XHTML thing, per
https://github.com/sveltejs/svelte/pull/17418#issuecomment-3863029273
(that PR doesn't address this issue)
### Before submitting the PR, please make sure you do the following
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## Summary
Fixes#13768
`<select bind:value={derived.prop}>` in legacy (non-runes) components
throws `effect_update_depth_exceeded` when the bound value comes from a
`$:` reactive statement.
**Root cause:** `setup_select_synchronization` created a
`template_effect` that called `invalidate_inner_signals`, which reads
and writes the same signals on every change — creating an infinite
update loop when those signals feed back into derived state.
**Fix:** Remove the effect-based synchronization entirely. Instead,
populate `legacy_indirect_bindings` during the analyze phase for
`<select bind:value>` elements, and call `invalidate_inner_signals`
inline at the mutation point in `AssignmentExpression` — only when the
binding is actually mutated, avoiding the read-write cycle.
Based on the approach outlined in #16200.
## Changes
- **`scope.js`**: Add `legacy_indirect_bindings` field to `Binding`
class
- **`RegularElement.js` (analyze)**: For `<select bind:value={foo}>`,
collect scope references as indirect bindings on the bound variable
- **`RegularElement.js` (transform)**: Remove
`setup_select_synchronization` function and its call site
- **`AssignmentExpression.js` (transform)**: When mutating a binding
with indirect bindings, append `invalidate_inner_signals` call after the
mutation
## Test plan
- Added `binding-select-reactive-derived` test that reproduces the exact
scenario from #13768
- All 3291 runtime-legacy tests pass (0 regressions)
- All 2312 runtime-runes tests pass
- All snapshot and compiler tests pass
---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Currently, the [newly introduced `parseCss` from
`svelte/compiler`](https://github.com/sveltejs/svelte/pull/17496)
returns `Omit<AST.CSS.StyleSheet, 'attributes' | 'content'>`. If you try
to work with this in external tooling, everywhere where you pass around
the result of this method, you need to use that type as well, which is
quite cumbersome. (I'm trying to integrate this into `sv` to get rid of
a workaround)
This creates a new type in the CSS AST to differentiate between one
stylesheet only having the roles, and one beeing the full one that is
used in `parse` itself. Im 100% open on the name of the new type or any
better ideas.
### Before submitting the PR, please make sure you do the following
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- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
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---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
This was actually several bugs:
- We used `scopes` for the blockers, that's actually the template
scopes, should be `instance.scopes` instead
- We missed setting the scope for `touch`
- We didn't take return statements into account when calculating
blockers. We cannot know when/if something within the return statement
is called, so we gotta assume it is and touch everything transitively
from it
Combined this fixes#17667 (and possibly other cases not showing up in
the issue tracker yet)
Initially I just thought "ok I guess we have to traverse into functions,
too" but then I thought that feels too unoptimized and came up with the
return-statement-inspection, at which point I discovered the other bugs.
### Before submitting the PR, please make sure you do the following
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discussed ahead of time. In many cases, features are absent for a
reason. For large changes, please create an RFC:
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- [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`.
- [x] This message body should clearly illustrate what problems it
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### Tests and linting
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* chore: update ESLint to v10
Update eslint and related plugins/configs. Bump CI lint job to Node 24
(ESLint 10 requires ^20.19.0 || ^22.13.0 || >=24). Replace removed
Linter.FlatConfig type with Linter.Config.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix: address new `no-useless-assignment` violations from ESLint 10
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* dedupe
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
* fix: reduce if block nesting
This reduces if block nesting similar to how we did it in #15250 (which got lost during the `await` feature introduction): If the if expression doesn't contain an await expression or is not dependent on a blocker that is not already resolved, then we can avoid creating a separate `$.if()` statement. The one trade-off is that we'll do re-invocations for all the conditions leading up to the condition that matches. Therefore non-simple if expressions are wrapper in `$.derived` to avoid excessive recomputations.
closes#17659 (~320 markers in prod mode possible now; less in dev because of our "wrap this component with devtime info" method)
helps with #15200
* tweak
* feedback
If the render tag is wrapped in `$.async`, that `$.async` call already contains surrounding markers, so we must not add our own to avoid hydration mismatches. Related to #17641, fixes#17225
* add xhtml tests
* unused
* tweak
* more tests
* tweak
* we don't need to actually check the HTML - if it's malformed in SSR or mount, it will throw
* same here
* unused, so we can revert this
* and this
---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* docs: wrap JSDoc URLs in @see and @link tags
* fix: move curly brace to end of URL
* chore: add changeset
* add link text
* regenerate
---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* fix: allow NaN in key blocks
* lol whoops
* Update packages/svelte/src/internal/client/dom/blocks/key.js
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
* treat menu element like ul/ol for a11y role checks
The <menu> element has the same implicit role (list) as <ul> and <ol>,
so it should receive the same treatment in a11y checks:
- Allow <menu role="list"> without redundant role warning (CSS
list-style:none can remove semantics, role restores them)
- Allow <menu> with interactive roles like menu, menubar, radiogroup,
tablist, tree, treegrid (same exceptions as ul/ol)
Fixes#8529
* changeset
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
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