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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.
---
### 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: 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 🤔
### 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: 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
- [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`
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
- [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
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
- [ ] 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: 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
- [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`
* 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
* 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>
* fix: exit resolved async blocks on correct node when hydrating
* expand test + fix
* tweak, add note to self
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
This is basically #17611, minus #17640, plus #17639. We need to add the $.next() call after render tags as well as components; rather than duplicating the logic, we can use is_standalone to determine when this is necessary (since this is what prevents $.append(...) from being used).
Fixes#17261Fixes#17608
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
The store invalidation detection in each blocks only checked for
Identifier and MemberExpression AST node types. This caused bind:
on iteration variables to silently fail when the expression used
logical operators (e.g. `{#each $store.items ?? [] as item}`).
Use expression metadata dependencies instead of AST type checking
to find store_sub bindings, which correctly handles all expression
shapes.
Fixes#14625
* fix: emit `each_key_duplicate` error in production
* fix: preserve key
* Update packages/svelte/src/internal/client/dom/blocks/each.js
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* Update packages/svelte/src/internal/client/dom/blocks/each.js
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* fix: ensure keys are validated
* fix silly test name
* fix: cover other case of duplicate keys
* emit error on hydration
* ensure the error is handled
* drop useless tests
* unused
* finish merge
* add lost check back
* chore: bump playwright (#17565)
* chore: bump playwright
* maybe this will help somehow?
* err whatever
* fix
* chore: allow testing in production env 2 (#17590)
* Revert "chore: allow testing in production env (#16840)"
This reverts commit ffd65e90fe.
* new approach
* fix: handle renderer.run rejections (#17591)
* fix: handle renderer run rejections
* add test
* changeset
* simplify
* explanatory comment
---------
Co-authored-by: Antonio Bennett <abennett@mabelslabels.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* fix: only create async functions in SSR output when necessary (#17593)
* fix: only create async functions in SSR output when necessary
* actually...
* simplify generated code a bit more
* simplify
* fix: merge consecutive text nodes during hydration for large text content (#17587)
* fix: merge consecutive text nodes during hydration for large text content
Fixes#17582
Browsers automatically split text nodes exceeding 65536 characters into
multiple consecutive text nodes during HTML parsing. This causes hydration
mismatches when Svelte expects a single text node.
The fix merges consecutive text nodes during hydration by:
- Detecting when the current node is a text node
- Finding all consecutive text node siblings
- Merging their content into the first text node
- Removing the extra text nodes
This restores correct hydration behavior for large text content.
* add test, fix
* fix
* fix
* changeset
---------
Co-authored-by: Miner <miner@example.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* Version Packages (#17585)
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
* Revert "drop useless tests"
This reverts commit 65f77ef840.
* update tests
* fix test
* we don't need to expose this function any more
* figured it out... we cant have errors during reconcile
* simplify
* tweak
* unused
* revert no-longer-needed change
* unused
---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: Antonio Bennett <31296212+Antonio-Bennett@users.noreply.github.com>
Co-authored-by: Antonio Bennett <abennett@mabelslabels.com>
Co-authored-by: FORMI <239411042+Richman018@users.noreply.github.com>
Co-authored-by: Miner <miner@example.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
* Remove SvelteKit data attributes from elements.d.ts
Removed SvelteKit specific data attributes from elements.d.ts.
* Remove SvelteKit data attributes from elements.d.ts
Removed SvelteKit data attributes from elements.d.ts.
---------
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
fixes#17595
When an if/key/etc block has an expression that depends on an async blocker (e.g., is inside a component with top level `await`), the compiler incorrectly treats the expression as async - even when the expression itself contains no `await`.
This causes the expression to be added to `$.async`'s `expressions` array, which wraps it in an `async_derived`. This is not only unnecessary but also buggy: it breaks the direct reactive connection between the source and its dependent effects, causing inconsistent effect executions.
The fix is to only add expressions to `$.async`'s `expressions` array when they actually contain an `await`.
When a branch is speculatively marked for destruction (condition temporarily falsy), its child effects are reset to `CLEAN` to prevent them running in a doomed branch (as of #17581). However, if the branch survives (condition becomes truthy again), those effects remain `CLEAN` and never run - the source was already marked dirty before the reset, so no new dirty marking occurs.
The fix is to change `skipped_effects` from a `Set` to a `Map` that tracks which child effects were dirty/maybe_dirty before being reset. When a branch is unskipped (survives), restore their status and reschedule them.
---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* fix: merge consecutive text nodes during hydration for large text content
Fixes#17582
Browsers automatically split text nodes exceeding 65536 characters into
multiple consecutive text nodes during HTML parsing. This causes hydration
mismatches when Svelte expects a single text node.
The fix merges consecutive text nodes during hydration by:
- Detecting when the current node is a text node
- Finding all consecutive text node siblings
- Merging their content into the first text node
- Removing the extra text nodes
This restores correct hydration behavior for large text content.
* add test, fix
* fix
* fix
* changeset
---------
Co-authored-by: Miner <miner@example.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* fix: prevent reactivity loss during fork
fixes#17197, fixes#17304, fixes#17301, fixes#17309
* add samples
* add changeset
* fix var casing in tests
* don't remove reactions during fork
* add sample for derived dep tracking in fork
* fix sample type check error
* set derived.v on first eval in fork
* add sample for derived.v remaining UNINITIALIZED
* lost current_batch import in runtime.js
* Delete how
* Update packages/svelte/src/internal/client/reactivity/deriveds.js
* delete test in favour of #17577
* extract runtime.js changes into separate PR
* alternative approach
* revert
* clear skipped branches when deferring
* fix
* fix
* changeset
* rename test
* update test
* unused test
---------
Co-authored-by: David Roizenman <david@hmnd.io>
Co-authored-by: Paolo Ricciuti <ricciutipaolo@gmail.com>
Co-authored-by: Tee Ming <chewteeming01@gmail.com>
* fix: make onintrostart respect delay parameter
Fixes#14009
The onintrostart event now fires after the delay period completes,
rather than immediately when the transition is initiated. This ensures
that the event accurately reflects when the intro animation actually
starts.
Changes:
- Added on_start callback parameter to animate() function
- Dispatch introstart event after delay animation finishes
- Handle edge case where duration is 0 but delay > 0
* fix: format code with prettier
* add (failing) tests
* fix
* changeset
* missed a spot
* fix
---------
Co-authored-by: Miner <miner@example.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
* fix: mark parent effect as dirty on error boundary initialization
This change ensures that if an error occurs while a parent effect is still initializing, the parent effect is marked as dirty and scheduled to re-run. This addresses scenarios where state updates in the onerror handler do not trigger a re-evaluation of the condition, improving error handling in Svelte components.
* chore: add changeset for #17553
* fix: run boundary callbacks in a microtask, in case they result in the boundary's destruction
---------
Co-authored-by: frozenflux2 <snowflake30518@gmail.com>
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