2580 Commits (svelte@5.55.7)

Author	SHA1	Message	Date
github-actions[bot]	4d8f99a270	Version Packages (#18220) ... 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@5.55.7 ### Patch Changes - fix: prevent XSS on `hydratable` from user contents ([`a16ebc67bbcf8f708360195687e1b2719463e1a4`](a16ebc67bb)) - chore: bump devalue ([#18219](https://github.com/sveltejs/svelte/pull/18219)) - fix: disallow empty attribute names during SSR ([`547853e2406a2147ad7fb5ffeba95b01bd9642da`](547853e240)) - fix: harden regex ([`d2375e2ebcab5c88feb5652f1a9d621b8f06b259`](d2375e2ebc)) - fix: move Svelte runtime properties to symbols ([`e1cbbd96441e82c9eb8a23a2903c0d06d3cda991`](e1cbbd9644)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	3 months ago
Rich Harris	0552308817	chore: bump devalue (#18219)	3 months ago
Elliott Johnson	e1cbbd9644	Merge commit from fork ... * fix: move Svelte runtime properties to symbols Prevents DOM clobbering * shorten names --------- Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>	3 months ago
Elliott Johnson	a16ebc67bb	Merge commit from fork ... https://github.com/sveltejs/svelte/security/advisories/GHSA-f3cj-j4f6-wq85 Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>	3 months ago
Simon H	d2375e2ebc	Merge commit from fork	3 months ago
Simon H	547853e240	Merge commit from fork ... * fix: disallow empty attribute names during SSR * Update packages/svelte/tests/server-side-rendering/samples/spread-attributes-event-handler-xss/main.svelte Co-authored-by: Conduitry <git@chor.date> --------- Co-authored-by: Elliott Johnson <hello@ell.iott.dev> Co-authored-by: Conduitry <git@chor.date>	3 months ago
github-actions[bot]	55f9c85c09	Version Packages (#18158) ... 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@5.55.6 ### Patch Changes - fix: leave stale promises to wait for a later resolution, instead of rejecting ([#18180](https://github.com/sveltejs/svelte/pull/18180)) - fix: keep dependencies of `$state.eager/pending` ([#18218](https://github.com/sveltejs/svelte/pull/18218)) - fix: reapply context after transforming error during SSR ([#18099](https://github.com/sveltejs/svelte/pull/18099)) - fix: don't rebase just-created batches ([#18117](https://github.com/sveltejs/svelte/pull/18117)) - chore: allow `null` for `pending` in typings ([#18201](https://github.com/sveltejs/svelte/pull/18201)) - fix: flush eager effects in production ([#18107](https://github.com/sveltejs/svelte/pull/18107)) - fix: rethrow error of failed iterable after calling `return()` ([#18169](https://github.com/sveltejs/svelte/pull/18169)) - fix: account for proxified instance when updating `bind:this` ([#18147](https://github.com/sveltejs/svelte/pull/18147)) - fix: ensure scheduled batch is flushed if not obsolete ([#18131](https://github.com/sveltejs/svelte/pull/18131)) - fix: resolve stale deriveds with latest value ([#18167](https://github.com/sveltejs/svelte/pull/18167)) - chore: remove unnecessary `increment_pending` calls ([#18183](https://github.com/sveltejs/svelte/pull/18183)) - fix: correctly compile component member expressions for SSR ([#18192](https://github.com/sveltejs/svelte/pull/18192)) - fix: reset `source.updated` stack traces after `flush` ([#18196](https://github.com/sveltejs/svelte/pull/18196)) - fix: replacing async 'blocking' strategy with 'merging' ([#18205](https://github.com/sveltejs/svelte/pull/18205)) - fix: allow `@debug` tags to reference awaited variables ([#18138](https://github.com/sveltejs/svelte/pull/18138)) - fix: re-run fallback props if dependencies update ([#18146](https://github.com/sveltejs/svelte/pull/18146)) - fix: abort running obsolete async branches ([#18118](https://github.com/sveltejs/svelte/pull/18118)) - fix: ignore comments when reading CSS values ([#18153](https://github.com/sveltejs/svelte/pull/18153)) - fix: wrap `Promise.all` in `save` during SSR ([#18178](https://github.com/sveltejs/svelte/pull/18178)) - fix: ignore false-positive errors of `$inspect` dependencies ([#18106](https://github.com/sveltejs/svelte/pull/18106)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	3 months ago
Rich Harris	a10e8e47a5	fix: keep dependencies of `$state.eager`/`pending` (alternative approach) (#18218) ... #18108, with two differences: - we use a global map - we use the parent reaction as the key, rather than traversing upwards for a branch I think this has the same outcome? ### 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 Holthausen <simon.holthausen@vercel.com> Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>	3 months ago
Rich Harris	5122936edb	fix: treat batches as a linked list (#18205) ... This is another attempt to address some of the tricky edge cases that arise when async batches resolve out of order. The idea is this: Essentially, when a batch resolves: 1. we find the latest batch it shares changes with 2. if none exists (either because this is the earliest batch, or because it is independent of any earlier batches): - we commit it: effects are flushed, `oncommit` callbacks are run - we restart any async work in later batches that depends on both the committed values and the later batch's changes 3. otherwise, we don't commit the batch. instead: - we merge the changes from the later batch onto the earlier batch. in some cases this may mean restarting async work on the earlier batch, but we avoid doing so unnecessarily. - we then `#process()` the earlier batch. if it resolves, goto 1 This feels like it ought to work. There are still two failing tests, which I'm currently looking into. Notable changes: - Instead of having a `batches` set, we have a linked list. When a batch resolves, this makes it easy to find the batch that it should be merged into - The `#is_deferred` logic now takes account of skipped effects — there's no need to wait for a promise inside a falsy `if` block (this accounts for the change in the `async-inner-after-outer` test) - We no longer care about `#blockers` I would like to believe that this approach will allow us to simplify and delete some code, for example the `rebase` logic, though that remains to be seen. It also feels like some version of #18035 would be helpful. - closes #18189 - closes #18162 - fixes https://github.com/sveltejs/kit/issues/15431 ### 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> Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>	3 months ago
Simon H	1688c84be9	chore: allow `null` for `pending` in typings (#18201) ... Closes #18166 We handle all falsy values at runtime already and for basically every other dom attribute also allow `null`, so no reason not to do this.	3 months ago
Rich Harris	9ffc13d7c3	fix: remove `source.updated` stack traces after `flush` (#18196) ... Noticed that we're not actually doing anything with `source_stacks` — we shadow the module-level declaration in `flush`, which means we just keep appending to it and then clearing a different (and empty) set. As a result, any source that ever gets an `updated` property never gets rid of it. This probably causes a memory leak? Anyway, this fixes it. ### 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`	3 months ago
Simon H	e00944ffd1	fix: correctly compile component member expressions for SSR (#18192) ... Fixes #18191	3 months ago
Rich Harris	908c9d0312	fix: leave stale promises to wait for a later resolution, instead of rejecting (#18180) ... This incorporates some of the fixes and insights from #18177, but gets rid of the `skip` logic. Instead, we differentiate between _stale_ and _obsolete_ promises. A promise is stale if it has been overtaken by a subsequent update, and was rejected with `STALE_REACTION`: ```ts async function search(query: string) { return fetch(`/search?q=${query}`, { signal: getAbortSignal() }).then((r) => r.json()); } ``` In this case, if we start typing `pot`, and then finish typing `potato`, the first promise will eventually resolve with the results for `/search?q=potato`, instead of the batch entering a weird limbo/zombie state. A promise is obsolete if it belongs to a now-destroyed effect, meaning that toggling `show` doesn't result in an accumulation of never-resolving batches: ```svelte {#if show} {await neverResolves()} {/if} ``` Fixes part of https://github.com/sveltejs/kit/issues/15431 --------- Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com> Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>	3 months ago
Simon H	1c150a460f	fix: abort running obsolete async branches (#18118) ... We shouldn't continue executing async work where we know the surrounding branch is destroyed already, it can leave to noisy "derived inter" warnings or even runtime errors ("cannot stringify symbol" when running a template effect with an uninitialized source). Neither should we warn about waterfalls on an already-destroyed async effect. Fixes #18097 (though strictly speaking that particular instance is also fixed by #18117 which fixes the underlying cause for the reruns; this one is necessary in itself though, as shown by the new test) --------- Co-authored-by: Rich Harris <rich.harris@vercel.com>	3 months ago
Rich Harris	91e1ead773	chore: remove unnecessary `increment_pending` calls (#18183) ... These might have been necessary at one point, but I'm confident they're unnecessary now — `increment_pending` happens (if necessary) inside `flatten`, which is called inside `async` and `deferred_template_effect`, so there's no need to call it inside those functions as well.	3 months ago
Simon H	aeb6bd088b	fix: reapply context after transforming error during SSR (#18099) ... Don't have a test for it and no bug report but I stumbled upon this and I'm very certain not restoring context here is wrong since it means the failed snippet rendering gets the wrong context. --------- Co-authored-by: Rich Harris <rich.harris@vercel.com>	3 months ago
Simon H	d4c5a91735	fix: rethrow error of failed iterable after calling `return()` (#18169) ... The fix in #17966 wasn't quite right, because we gotta rethrow in case the iterator stopped because of an error. Fixes part of the SvelteKit `query.live` test failure. --------- Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com> Co-authored-by: Rich Harris <rich.harris@vercel.com>	3 months ago
Paolo Ricciuti	89b6a939fe	fix: wrap `Promise.all` in `save` during SSR (#18178) ... Closes #18168 Not sure if there's a deeper issue in play because the error it's only really there if you also add a title to the component. I think the issue is that with multiple arguments the top level `Promise.all` is not wrapped in `save` and that probably causes a race condition with `title` that sets the context back to `null` in a `finally`. One issue is that now the generated code looks like this ```js const [$$0, $$1] = (await $.save(Promise.all([ (async () => (await $.save(user()))().name)(), (async () => (await $.save(user()))().image)() ])))(); ``` which seems a bit redundant, but I'm not sure if we can get rid of the inner `save` since they are indeed awaiting something.	3 months ago
Rich Harris	dc5bd887b5	fix: resolve stale deriveds with latest value (#18167) ... While looking into #18162 I found an adjacent bug. Currently, if an async derived resolves in batch 2 before it resolves in batch 1, we reject the promise belonging to batch 1 and by extension the batch itself. This means that any other changes in batch 1 are silently discarded, incorrectly. The fix is almost comically simple: rather than rejecting the earlier promise, we just resolve it with the latest value. I have a hunch that this might also enable us to simplify the rebase logic, though I haven't investigated that in this PR. ### Before submitting the PR, please make sure you do the following - [x] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs - [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`. - [x] This message body should clearly illustrate what problems it solves. - [x] Ideally, include a test that fails without this PR but passes with it. - [x] If this PR changes code within `packages/svelte/src`, add a changeset (`npx changeset`). ### Tests and linting - [x] Run the tests with `pnpm test` and lint the project with `pnpm lint`	3 months ago
Simon H	572444a696	fix: ignore false-positive errors of `$inspect` dependencies (#18106) ... We had logic in place to ignore errors of `$inspect` effects that are about to destroy, but we didn't take into account that we can get these transient errors while checking for `is_dirty` in preparation for running the effect, too. Now effects are marked as dirty in case an error occurs while evaluating their dependencies, which guarantees we will see the error again but we can then handle it properly. Fixes #15741 --------- Co-authored-by: Rich Harris <rich.harris@vercel.com>	3 months ago
Simon H	90a70cb012	fix: flush eager effects in production (#18107) ... While working on #18106 I noticed that we're not adding eager effects inside `mark_reactions` when `DEV` is `false`. As a result production build could have `$state.eager` or `$state.pending` not working correctly. ~No test because I can't get Vitest to not run with `DEV` being `true`.~ added a test	3 months ago
Simon H	9521b9f3dc	fix: don't rebase just-created batches (#18117) ... It's possible to rebase just-created batches. Case A: - batch A runs effects - one of these effects writes to a source. This creates a new batch B - an effect _after_ that (still part of "flush effects of batch A") executes a derived. This creates an entry in the `current` Map in batch B - batch A commits after processing batch B (`next_batch` etc logic), batch B is pending. Due to derived being part of batchB.current batch A can wrongfully think these are connected and try to rerun/add effects etc on batch B Case B: - like case A but with an additional await inside a pending snippet Case C: - batch A with source a and b, it flushes effects - one of these effects schedules batch B with b and c scheduling an async effect - batch B is deferred - batch A commits. Due to the a/b/c partial overlap it will needlessly rerun the just scheduled async effect All these cases are wrong. We fix it like this: 1. we call `this.#commit()` _before_ running the new batches, which may stick around due to having pending work, and we don't want to rebase these. This fixes case A and C 2. we capture derived values in `previous_batch` if it exists, because it means we're currently flushing effects, and derived writes belong to that batch and not a new one that might have been scheduled already. This fixes case B Discovered this while working on #18097 --------- Co-authored-by: Rich Harris <rich.harris@vercel.com>	4 months ago
Eduardo Kurek	146cb5ea6c	fix: lazy props reactivity (#18146) ... Fix #18132 This PR treat lazy fallbacks on `prop()` as derived. Now a default function that uses a $state is recalculated whenever its dependents changes. This change implies that this lazy functions cannot mutate a state anymore (because it is derived), causing a `state_unsafe_mutation`error. This implies on a breaking change, but reasonable. --- ### New breaking change here - **Who does this affect**: Everyone that has updated a $state on a default lazy prop. Example: ```html <script> let myValue = $state(0); let callCount = $state(0); function getValue() { callCount++; // causes a state_unsafe_mutation error return myValue; // returning a state doesn't cause an error, and now it is tracked as a dependency } let { value = getValue() } = $props(); </script> ``` **Why make this breaking change** This encourages people to not update states on a function that fundamentaly, is readonly. When someone wants to use a default function expecting that it should be tracked, its not likely that this function will change some state. It is anti-pattern to change some state inside a getter function. But what if someone wants to do it, like in the code above? The code above doesn't make sense before this PR, the old way to calculate lazy functions is to execute it one time, and only one, so the `callCount` variable will never change. But let's assume that someone did it, how to migrate? The migration in same example is easy, since the `callCount` is executed only once, it will not be executed after the component is mounted. So the `callCount` doesn't need to be a state, the `callCount` will be in a valid state when the component is created. So here is the migrated code: ```html <script> let myValue = $state(0); let callCount = 0; function getValue() { callCount++; // doesn't causes an error return myValue; } let { value = getValue() } = $props(); </script> ``` As we can see, there is no reason for the variable `callCount` in this example (before this PR), and if someone did it, it is more likely that they used a constant instead: ```html <script> let myValue = $state(0); let callCount = 1; function getValue() { return myValue; } let { value = getValue() } = $props(); </script> ``` There is another example that causes the `state_unsafe_mutation` and how to fix (this happened on the tests that i changed): ```html <script> let log = $state([]); function fallbackExample => { log.push('fallback called'); return 1; // any value, just to show the issue with the log } let { value = fallbackExample() } = $props(); </script> ``` Here, we can see that `log` variable is a state. Before this PR, as i said, this function `fallbackExample` will be executed once. So the logs will be computed when the component is mounted. So there is no reason to make the `log` a state. The simplest way to fix this is to make it a normal variable: ```html <script> let log = []; </script> ``` But with this PR, the function might be recalculated at some point, and the `log` with a state makes sense now, so how to migrate in this case? As i said, changing a state inside a lazy prop function is not a good practice, we can think in a way to invert this dependency, and change the approach from push (imperative mutation) to pull (declarative derivation). If a developer really needs to track how many times a fallback is executed or react to its changes, they should use a $derived or an $effect that observes the same dependencies as the fallback, or simply observe the property itself: ```html <script> let { value = fallbackExample() } = $props(); let log = $state([]); $effect(() => { const message = `${value}`; untrack(() => { // we don't want to track changes on the log variable log.push(message); }); }); </script> ``` ### After all, how to migrate? 1. **If there is no state mutation inside the prop function, no need to changes**; 2. **If there is a state mutation inside the prop function, but the value muted is declared inside the same component:** remove the state from it. Before this PR the method will be executed only once, and to get the same result, you do not need the variable to be a state; **Before** ```html <script> let log = $state([]); const fallback_fn = () => { log.push('fallback_fn'); return 1; } const { myProp = fallback_fn() } = $props(); </script> ``` **After** ```html <script> let log = []; const fallback_fn = () => { log.push('fallback_fn'); return 1; } const { myProp = fallback_fn() } = $props(); </script> ``` 3. **If there is a state mutation inside the prop function, and the value is read in multiple places:** change your approach, use a effect to detect the change on the prop, and apply your mutation inside the effect; Before: ```html <script> import { setLog } from './logs.js'; // setLog apply a mutation on a state const fallback_fn = () => { setLog('fallback_fn'); return 1; } const { myProp = fallback_fn() } = $props(); </script> ``` After ```html <script> import { setLog } from './logs.js'; // setLog apply a mutation on a state const fallback_fn = () => { return 1; } const { myProp = fallback_fn() } = $props(); $effect(() => { const message = `${myProp}`; untrack(() => { setLog(message); }); }); </script> ``` ### Severity (number of people affected x effort): Low - **Affected Users:** Minimal. Mutating state inside a property initializer is a rare edge case and considered an anti-pattern (because its a side effect inside a getter). Most users use constants or pure functions for fallbacks. - **Migration Effort:** Low. As demonstrated in the examples above, the fix usually involves either removing an unnecessary $state or moving the side effect to its proper place, the $effect ### Conclusion This PR encourages users to program in a better way. Forcing a clean separation between data and their side effects. The developer can use this new feature mainly in i18n services, providing better usability and experience. Also, this PR makes the properties more predictable, since the expected behavior is that it works reactively, eliminating this bug for future developers. Even though this PR adds a breaking change, it's easily solvable, and the chance of any user facing this problem is low. **Full example to test reactivity in props** (won't work on web, you can get the PR and test localy to see it working): https://svelte.dev/playground/a6608434d8c642179f0e2b72468c74d7?version=latest *A unit test for this reactivity was created: runtime-runes/props-default-value-reactivity*. --------- Co-authored-by: Rich Harris <rich.harris@vercel.com> Co-authored-by: Rich Harris <hello@rich-harris.dev>	4 months ago
Simon H	bc82a55647	fix: ensure scheduled batch is flushed if not obsolete (#18131) ... The logic of checking that the current batch is still the generated one is flawed. If microtasks align the current batch can be a different value even if the batch still need to be flushed. This therefore switches the heuristic to what it actually should express: "has this batch run already?" Fixes #18126 (because the batch isn't running, it later runs into the invariant)	4 months ago
Simon H	4c96b469f8	fix: allow `@debug` tags to reference awaited variables (#18138) ... Fixes #18137	4 months ago
Dor Alagem	69b4c9f561	fix: skip block comments in read_value to prevent apostrophe parsing error (#18153) ... Fixes #18134. ## Problem `read_value()` in `packages/svelte/src/compiler/phases/1-parse/read/style.js` has no logic to skip CSS block comments (`/* ... */`). When the parser encounters an apostrophe inside a comment, it sets `quote_mark = "'"` — treating it as the start of a string literal — then never finds a matching closing quote, and ultimately throws `unexpected_eof` at the end of the style block. Minimal repro: ```svelte <style> /* it's a comment */ .foo { color: red; } </style> ``` → `Error: Unexpected end of input` ## Fix Add a `/* ... */` skip path inside the `read_value` loop, mirroring the same pattern already used in `allow_comment_or_whitespace`. When `/*` is detected outside a string or url context, the parser advances past the entire comment without adding its content to the value string. --------- Co-authored-by: Dor Alagem <doralagem@MacBook-Pro-sl-Dor.local> Co-authored-by: Rich Harris <rich.harris@vercel.com>	4 months ago
7nik	ada3076967	fix: account for proxified instance when updating `bind:this` (#18147) ... Fixes #18145 I wonder why nulling happens after updating `bind:this` but not before, which would fix the issue as well, though not as efficiently. ### 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`	4 months ago
github-actions[bot]	b771df3464	Version Packages (#18125) ... 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@5.55.5 ### Patch Changes - fix: don't mark deriveds while an effect is updating ([#18124](https://github.com/sveltejs/svelte/pull/18124)) - fix: do not dispatch introstart event with animation of animate directive ([#18122](https://github.com/sveltejs/svelte/pull/18122)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	4 months ago
Simon H	8e7319063a	fix: don't mark deriveds while an effect is updating (#18124) ... Fixes #18123 This makes setting state inside effects slightly slower theoretically (since they hit the new guard), but I verified that the original issue for which we introduced this (#16658) is still fast with this change. The more we add logic to this the more I think we should investigate switching to a different mechanism. I tried using a `Set` previously but it did hurt the benchmarks a bit - might try to revisit a variant of this. --------- Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>	4 months ago
dabund24	51736e576d	fix: do not dispatch transition event with animation (#18122) ... closes #18056 related: #17567 and #14009 # Changes move `dispatch_event()` calls in `transitions.js` out of `animate()` function using an additional `on_begin()` callback parameter. Doing so makes it possible to dispatch the `introstart` and `outrostart` events only from `transition()`. # Testing add a test checking that svelte dispatches no event when it runs an animation	4 months ago
github-actions[bot]	7fddfbdbbd	Version Packages (#18105) ... 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@5.55.4 ### Patch Changes - fix: never mark a child effect root as inert ([#18111](https://github.com/sveltejs/svelte/pull/18111)) - fix: reset context after waiting on blockers of `@const` expressions ([#18100](https://github.com/sveltejs/svelte/pull/18100)) - fix: keep flushing new eager effects ([#18102](https://github.com/sveltejs/svelte/pull/18102)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	4 months ago
Simon H	671fc2ea11	fix: never mark a child effect root as inert (#18111) ... A nested `$effect.root` was marked `INERT` during `pause_children`, which caused it to stay in that state indefinetly after the rest of the parent tree was destroyed. Consequently deriveds inside no longer update and cause warnings. This fixes it by not marking nested `$effect.root`s as inert, just like nested `$effect.root`s are not destryoed and instead become a new root. Fixes #18097	4 months ago
Simon H	0ed8c282f9	fix: reset context after waiting on blockers of `@const` expressions (#18100) ... Regression from #18039 - we need to have each await expression (and waiting on blockers is one) in its own entry of `(renderer.)run`. Else context is not restored correctly and if the synchronous expression afterwards requires it stuff breaks. Fixes #18098	4 months ago
Simon H	273f1a85a4	fix: keep flushing new eager effects (#18102) ... The previous code "swallowed" new additions to the array of eager effects that happened while flushing since `eager_flush` did not clear the array before running, only afterwards. Now it clears the beforehand, causing newly added eager effects to run, too. An example where this can happen is `$state.eager` and `$effect.pending` in combination: first `$state.eager` is flushed, then due to `flushSync` the `queue_micro_task` inside `boundary.js` that flushes `$effect.pending` is triggered synchronously, adding new entries to the `eager_versions` array. If they're only cleared at the end of `eager_flush`, new entries are swallowed. Related to #18095 (but not fixing it yet)	4 months ago
github-actions[bot]	4a50e8ea3b	Version Packages (#18085) ... 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@5.55.3 ### Patch Changes - fix: ensure proper HMR updates for dynamic components ([#18079](https://github.com/sveltejs/svelte/pull/18079)) - fix: correctly calculate `@const` blockers ([#18039](https://github.com/sveltejs/svelte/pull/18039)) - fix: freeze deriveds once their containing effects are destroyed ([#17921](https://github.com/sveltejs/svelte/pull/17921)) - fix: defer error boundary rendering in forks ([#18076](https://github.com/sveltejs/svelte/pull/18076)) - fix: avoid false positives for reactivity loss warning ([#18088](https://github.com/sveltejs/svelte/pull/18088)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	4 months ago
Simon H	15588f5fbf	fix: avoid false positives for reactivity loss warning (#18088) ... Avoids two categories of false positives for reactivity loss warning: 1. if you have synchronously read signals already as part of invoking the async_derived function, then it shouldn't warn when these signals are read after an await if we know they haven't changed (we check the write version for that) 2. `track_reactivity_loss` kept the `reactivity_loss_tracker` around indefinitely, both when invoking the async operation as well as when it's finished. The former is buggy because while the async operation happens unrelated reads as part of other reactivity work can happen, the latter is buggy because if it's the last in a chain of awaits it's kept around until the next async work starts. Fixes https://github.com/sveltejs/kit/issues/15654 --------- Co-authored-by: Rich Harris <rich.harris@vercel.com> Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>	4 months ago
Rich Harris	0e9e76f292	fix: freeze deriveds once their containing effects are destroyed (#17921) ... Per https://github.com/sveltejs/svelte/pull/17862#issuecomment-4049752548, this freezes the value of a derived if it was created inside a parent effect that is now destroyed. This prevents the sort of bug where a derived reads `foo.bar` even though `foo` is now `undefined`. If the derived is dirty, a warning will be printed. This PR also gets rid of some weirdness around `derived.parent` — it can only ever be an `Effect | null`, and there's no need for `get_derived_parent_effect`. Blocked on https://github.com/sveltejs/kit/pull/15533 and a follow-up that switches remote functions to use `$effect.root` (since this effectively undoes #17171), hence draft. ### Before submitting the PR, please make sure you do the following - [x] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs - [x] Prefix your PR title with `feat:`, `fix:`, `chore:`, or `docs:`. - [x] This message body should clearly illustrate what problems it solves. - [x] Ideally, include a test that fails without this PR but passes with it. - [x] If this PR changes code within `packages/svelte/src`, add a changeset (`npx changeset`). ### Tests and linting - [x] Run the tests with `pnpm test` and lint the project with `pnpm lint` --------- Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com> Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>	4 months ago
Simon H	3937ec03bd	fix: correctly calculate `@const` blockers (#18039) ... Move the calculation of blockers into the analysis phase and then only push the right thunks in the transform phase - similar to how we already do it with top level `$.run` Fixes #18024 The solution is a tiny bit brittle (not much more than the top level one we already have) and I tried to make it a bit more robust but ended up in a rabbit hole in #18032 - we can revisit that solution once all the old stuff is gone. Until then this is the most pragmatic/non-invasive change. --------- Co-authored-by: Rich Harris <rich.harris@vercel.com>	4 months ago
Simon H	7be1a0247f	fix: ensure proper HMR updates for dynamic components (#18079) ... The BranchManager in `branches.js` does create a temporary anchor when creating a new branch offscreen, and deletes it once the branch is committed. Normally this is fine, but the combination of HMR and dynamic components leads to a bug: Since `svelte-component.js` passes the temporary anchor along to the component it generates, which is the HMR wrapper, this wrapper will have an obsolete, disconnected anchor on updates, leading to the content disappearing. The fix is to add a dev-only symbol which we set on the original (then obsolete) anchor to tell about the updated anchor that should be used for HMR updates. Fixes https://github.com/sveltejs/kit/issues/14699 Fixes #17211	4 months ago
Simon H	a4ce776070	fix: defer error boundary rendering in forks (#18076) ... RIght now, when an async error occurs inside a fork, the error UI will show immediately. This change defers the removal of the current content etc until the fork is committed. The BranchManager logic cannot be reused here since this is not about pending work, and we cannot wait for other pending work to complete if the fork commits. Instead, batches now have a "on fork commit" callback set which the boundary pushes to. The boundary's effects are skipped in the fork until it's committing, at which point we "resume" the error logic (calling onerror, transforming it, etc) Fixes #18060	4 months ago
github-actions[bot]	2e29c87cc9	Version Packages (#18036) ... 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@5.55.2 ### Patch Changes - fix: invalidate `@const` tags based on visible references in legacy mode ([#18041](https://github.com/sveltejs/svelte/pull/18041)) - fix: handle parens in template expressions more robustly ([#18075](https://github.com/sveltejs/svelte/pull/18075)) - fix: disallow `--` in `idPrefix` ([#18038](https://github.com/sveltejs/svelte/pull/18038)) - fix: correct types for `ontoggle` on `<details>` elements ([#18063](https://github.com/sveltejs/svelte/pull/18063)) - fix: don't override `$destroy/set/on` instance methods in dev mode ([#18034](https://github.com/sveltejs/svelte/pull/18034)) - fix: unskip branches of earlier batches after commit ([#18048](https://github.com/sveltejs/svelte/pull/18048)) - fix: never set derived.v inside fork ([#18037](https://github.com/sveltejs/svelte/pull/18037)) - fix: skip rebase logic in non-async mode ([#18040](https://github.com/sveltejs/svelte/pull/18040)) - fix: don't reset status of uninitialized deriveds ([#18054](https://github.com/sveltejs/svelte/pull/18054)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	4 months ago
Rich Harris	8966601dcd	fix: handle parens in template expressions more robustly (#18075) ... While looking into #17954 I realised that a) our code for handling parentheses in expressions is unnecessarily convoluted and b) it doesn't handle the case where you have an opening parent outside the first comment — this fails to parse: ```svelte {(/**/ 42)} ``` This fixes it and simplifies the code a good bit. ### 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`	4 months ago
Simon H	0395ef0df7	fix: unskip branches of earlier batches after commit (#18048) ... Fixes #17571 where the situation is the following: A derived creates a new query. That query initializes loading with true. This means the if block is marked for destruction (therefore effects inside branch are skipped), but it's not doing that yet because the query promise is pending. Then query resolves and loading is set back to false right before resolving, but it's not the same tick so `loading=false` is a separate thing. Because that later batch doesn't see any overlap with an earlier batch (the earlier batch did set loading to true but not via set but indirectly via recreating the query) it doesn't wait on it and flushes right away. Now the if block is marked as visible again but the earlier batch doesn't know that if noone unskips its branch. If we don't do that the render effect that is now dirty as part of that batch will not run.	4 months ago
Rich Harris	cd5bda00a8	chore: fix changeset (#18073) ... prevents the changelog from getting borked up	4 months ago
Simon H	d86cb5cc32	fix: skip rebase logic in non-async mode (#18040) ... Fixes part of #17940 (the hydration->error thing still needs a repro). Essentially in sync mode render effects are executed during traversing the effect tree, and when flushSync is called during that it can cause the timing of things getting out of sync such that you end up wanting to rebase another branch, which is never needed in sync mode. So we just skip that logic in sync mode. Another way would be to adjust flushSync such that it does appends itself to the end of the current flushing cycle if it notices processing is already ongoing. This will not work when you pass a callback function to `flushSync` though - another indicator that we should probably remove that callback argument. --------- Co-authored-by: Rich Harris <rich.harris@vercel.com> Co-authored-by: Rich Harris <hello@rich-harris.dev>	4 months ago
Simon H	adba758067	fix: don't reset status of uninitialized deriveds (#18054) ... If a new branch is created (e.g. if block becomes truthy) inside a fork and a derived is read inside the new branch for the first time, it will get reactions but its true value will stay uninitialized due to the fork. If the fork then commits, it will NOT change its value because it will not reexecute: there is no effect running after commit telling it to do that, because it was only read inside new effects which already ran while still inside the fork. Now, when that branch is removed (e.g. if block becomes falsy), the derived loses its reactions again and becomes disconnected, at which point the status is reset. So we end up with a maybe_dirty or clean derived and an uninitialized value, causing breakage if it's called again afterwards. The fix is to not reset the status in this case. Fixes https://github.com/sveltejs/kit/issues/15126 Fixes https://github.com/sveltejs/kit/issues/15318 Fixes https://github.com/sveltejs/kit/issues/15061	4 months ago
ottomated	14adb8caa9	fix: correct types for `ontoggle` on <details> elements (#18063) ... `<details>` elements fire `ontoggle` as ToggleEvents ([source](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/toggle_event)), but they're currently just typed as Event. ### 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:`. - [ ] 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`	4 months ago
Rich Harris	c93e251654	fix: never set derived.v inside fork (#18037) ... This started out as me implementing https://github.com/sveltejs/svelte/pull/17998/changes#r3018047965, but then I realised that I'd also fixed the bug that #17998 addresses. So I guess it's an alternative to that PR --------- Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>	4 months ago
Rich Harris	edcbb0e640	fix: invalidate `@const` tags based on visible references in legacy mode (#18041) ... closes #17992	4 months ago
Rich Harris	ff3495dc05	fix: disallow `--` in `idPrefix` (#18038) ... supersedes #17993	4 months ago