11033 Commits (avoid-reschedule-during-branch-commit)

 

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Author	SHA1	Message	Date
Rich Harris	d1b227395c	changeset	1 day ago
Rich Harris	b94f4436aa	tidy up	1 day ago
Rich Harris	42db628b5f	handle the reverse case	1 day ago
Rich Harris	58b7c135db	WIP	1 day ago
Rich Harris	363fa5a695	note to self	1 day ago
Rich Harris	942d9f230c	WIP	1 day ago
Rich Harris	cedd2abd9f	Merge branch 'main' into reschedule-during-traverse	1 day ago
Rich Harris	4aa3777271	chore: better log_effect_tree (#17833) ... 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>	1 day ago
Rich Harris	69c628d8d0	tidy up	1 day ago
Rich Harris	d93dfc9023	perf: avoid rescheduling effects when resuming	1 day ago
Vercel	7c7797f62c	Fix: The `child_is_reachable` calculation in `log_effect_tree` fails to incorporate the parent's `is_reachable` state, causing descendant effects to be incorrectly marked as reachable when an ancestor is unreachable. ... This commit fixes the issue reported at packages/svelte/src/internal/client/dev/debug.js:130 **Bug Explanation:** The `log_effect_tree` function recursively traverses an effect tree to log effects and mark "unreachable-but-dirty" effects with a warning. The function receives an `is_reachable` parameter indicating whether the current effect is reachable based on its ancestors. At line 130, the original code was: ```javascript var child_is_reachable = (flags & BRANCH_EFFECT) === 0 || (flags & CLEAN) === 0; ``` This calculation determines reachability for children based only on whether the *current* effect would block propagation (being a clean BRANCH_EFFECT). However, it completely ignores the incoming `is_reachable` parameter. **Example scenario where the bug manifests:** - Root (reachable) → `is_reachable = true` - Branch A: clean BRANCH_EFFECT → passes `child_is_reachable = false` to children - Branch B: dirty BRANCH_EFFECT → receives `is_reachable = false`, but calculates `child_is_reachable = false || true = true` - Effect C: dirty → receives `is_reachable = true` (WRONG!) Effect C should be marked as unreachable with a warning (⚠️) because its ancestor Branch A is a clean branch that doesn't propagate updates. Instead, it would appear as reachable because Branch B is dirty, and the original code doesn't carry forward the unreachability. **The Fix:** Changed the calculation to combine the inherited reachability with the current effect's contribution: ```javascript var child_is_reachable = is_reachable && ((flags & BRANCH_EFFECT) === 0 || (flags & CLEAN) === 0); ``` Now: - If `is_reachable` is already `false` (from an ancestor), children remain unreachable regardless of the current effect's state - If `is_reachable` is `true`, the original logic applies to determine if THIS effect makes children unreachable This ensures unreachability properly propagates down the entire subtree once an ancestor clean branch is encountered. Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com> Co-authored-by: Rich-Harris <hello@rich-harris.dev>	1 day ago
Rich Harris	c7c80edca2	chore: better log_effect_tree	1 day ago
Rich Harris	15e1e73f9c	chore: add `batch.id` property (#17831) ... 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	2 days ago
github-actions[bot]	d4c78292ed	Version Packages (#17812) ... 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@5.53.6 ### Patch Changes - perf: optimize parser hot paths for faster compilation ([#17811](https://github.com/sveltejs/svelte/pull/17811)) - fix: `SvelteMap` incorrectly handles keys with `undefined` values ([#17826](https://github.com/sveltejs/svelte/pull/17826)) - fix: SvelteURL `search` setter now returns the normalized value, matching native URL behavior ([#17828](https://github.com/sveltejs/svelte/pull/17828)) - fix: visit synthetic value node during ssr ([#17824](https://github.com/sveltejs/svelte/pull/17824)) - fix: always case insensitive event handlers during ssr ([#17822](https://github.com/sveltejs/svelte/pull/17822)) - chore: more efficient effect scheduling ([#17808](https://github.com/sveltejs/svelte/pull/17808)) - perf: optimize compiler analysis phase ([#17823](https://github.com/sveltejs/svelte/pull/17823)) - fix: skip redundant batch.apply ([#17816](https://github.com/sveltejs/svelte/pull/17816)) - chore: null out current_batch before committing branches ([#17809](https://github.com/sveltejs/svelte/pull/17809)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	3 days ago
Mathias Picker	361b32c7cd	fix: SvelteURL search setter uses unnormalized value (#17828) ... ## 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>	3 days ago
Rich Harris	6e9b2a6fd8	docs: best practices (#17804) ... Based on #17727 but with a few changes: - smaller (fewer tokens) - removed some bits that are really just summarising existing docs - added an explicit 'don't use these legacy features' section - shuffled some things around a bit --------- Co-authored-by: paoloricciuti <ricciutipaolo@gmail.com> Co-authored-by: Federico Varano <50919335+fvarano@users.noreply.github.com> Co-authored-by: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>	3 days ago
Mathias Picker	1043f79d1e	perf: optimize compiler analysis phase (#17823) ... ## 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>	3 days ago
Paolo Ricciuti	b6faa2a905	fix: always case insensitive event handlers during ssr (#17822) ... 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>	3 days ago
Paolo Ricciuti	e3d277b000	fix: visit synthetic value node during ssr (#17824) ... 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`	3 days ago
Tee Ming	a10cf95ca7	chore: add funding manifest URL (#17827) ... Related to https://github.com/sveltejs/svelte.dev/pull/1632 This will allow us to apply for a grant from floss.fund ### 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`	3 days ago
Mathias Picker	18db0cab86	fix: SvelteMap incorrectly handles keys with `undefined` values (#17826) ... ## 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>	3 days ago
Rich Harris	3fc4bc6774	chore: remove unused is_flushing variable (#17820) ... as of a few PRs ago this variable is unused	3 days ago
Rich Harris	16a13517ef	fix: skip redundant batch.apply (#17816) ... tiny fix — just realised we're calling `this.apply()` (via `this.activate()`) unnecessarily, since it will happen again immediately after in `flush_effects`	4 days ago
Gautier Ben Aïm	10380c2309	docs: fix list item (#17815) ... Fixes the formatting for this list https://svelte-dev-git-sync-svelte-svelte.vercel.app/docs/svelte/v5-migration-guide#Whitespace-handling-changed Follow up #17806	4 days ago
Rich Harris	04ba134d33	docs: flesh out `attribute_invalid_sequence_expression` message (#17789) ... closes #1404	4 days ago
Gautier Ben Aïm	d83e4be1f0	docs: document the {' '} trick (#17806) ... Hi! I run into this issue today, and found the fix in https://github.com/sveltejs/svelte/issues/16680#issuecomment-3229435832 I thought it would be a nice addition to the documentation (it's where I looked first) ### 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. - [ ] 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` --------- Co-authored-by: Rich Harris <hello@rich-harris.dev>	4 days ago
dependabot[bot]	fc67c9cfe9	chore(deps-dev): bump rollup from 4.52.5 to 4.59.0 (#17810) ... Bumps [rollup](https://github.com/rollup/rollup) from 4.52.5 to 4.59.0. <details> <summary>Release notes</summary> <p><em>Sourced from <a href="https://github.com/rollup/rollup/releases">rollup's releases</a>.</em></p> <blockquote> <h2>v4.59.0</h2> <h2>4.59.0</h2> <p><em>2026-02-22</em></p> <h3>Features</h3> <ul> <li>Throw when the generated bundle contains paths that would leave the output directory (<a href="https://redirect.github.com/rollup/rollup/issues/6276">#6276</a>)</li> </ul> <h3>Pull Requests</h3> <ul> <li><a href="https://redirect.github.com/rollup/rollup/pull/6275">#6275</a>: Validate bundle stays within output dir (<a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> </ul> <h2>v4.58.0</h2> <h2>4.58.0</h2> <p><em>2026-02-20</em></p> <h3>Features</h3> <ul> <li>Also support <code>__NO_SIDE_EFFECTS__</code> annotation before variable declarations declaring function expressions (<a href="https://redirect.github.com/rollup/rollup/issues/6272">#6272</a>)</li> </ul> <h3>Pull Requests</h3> <ul> <li><a href="https://redirect.github.com/rollup/rollup/pull/6256">#6256</a>: docs: document PreRenderedChunk properties including isDynamicEntry and isImplicitEntry (<a href="https://github.com/njg7194"><code>@​njg7194</code></a>, <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6259">#6259</a>: docs: Correct typo and improve sentence structure in docs for <code>output.experimentalMinChunkSize</code> (<a href="https://github.com/millerick"><code>@​millerick</code></a>, <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6260">#6260</a>: fix(deps): update rust crate swc_compiler_base to v47 (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6261">#6261</a>: fix(deps): lock file maintenance minor/patch updates (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6262">#6262</a>: Avoid unnecessary cloning of the code string (<a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6263">#6263</a>: fix(deps): update minor/patch updates (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6265">#6265</a>: chore(deps): lock file maintenance (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6267">#6267</a>: fix(deps): update minor/patch updates (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6268">#6268</a>: chore(deps): update dependency eslint-plugin-unicorn to v63 (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6269">#6269</a>: chore(deps): update dependency lru-cache to v11 (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6270">#6270</a>: chore(deps): lock file maintenance (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6272">#6272</a>: forward NO_SIDE_EFFECTS annotations to function expressions in variable declarations (<a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> </ul> <h2>v4.57.1</h2> <h2>4.57.1</h2> <p><em>2026-01-30</em></p> <h3>Bug Fixes</h3> <ul> <li>Fix heap corruption issue in Windows (<a href="https://redirect.github.com/rollup/rollup/issues/6251">#6251</a>)</li> <li>Ensure exports of a dynamic import are fully included when called from a try...catch (<a href="https://redirect.github.com/rollup/rollup/issues/6254">#6254</a>)</li> </ul> <h3>Pull Requests</h3> <ul> <li><a href="https://redirect.github.com/rollup/rollup/pull/6251">#6251</a>: fix: Isolate and cache <code>process.report.getReport()</code> calls in a child process for robust environment detection (<a href="https://github.com/alan-agius4"><code>@​alan-agius4</code></a>, <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> </ul> <!-- raw HTML omitted --> </blockquote> <p>... (truncated)</p> </details> <details> <summary>Changelog</summary> <p><em>Sourced from <a href="https://github.com/rollup/rollup/blob/master/CHANGELOG.md">rollup's changelog</a>.</em></p> <blockquote> <h2>4.59.0</h2> <p><em>2026-02-22</em></p> <h3>Features</h3> <ul> <li>Throw when the generated bundle contains paths that would leave the output directory (<a href="https://redirect.github.com/rollup/rollup/issues/6276">#6276</a>)</li> </ul> <h3>Pull Requests</h3> <ul> <li><a href="https://redirect.github.com/rollup/rollup/pull/6275">#6275</a>: Validate bundle stays within output dir (<a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> </ul> <h2>4.58.0</h2> <p><em>2026-02-20</em></p> <h3>Features</h3> <ul> <li>Also support <code>__NO_SIDE_EFFECTS__</code> annotation before variable declarations declaring function expressions (<a href="https://redirect.github.com/rollup/rollup/issues/6272">#6272</a>)</li> </ul> <h3>Pull Requests</h3> <ul> <li><a href="https://redirect.github.com/rollup/rollup/pull/6256">#6256</a>: docs: document PreRenderedChunk properties including isDynamicEntry and isImplicitEntry (<a href="https://github.com/njg7194"><code>@​njg7194</code></a>, <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6259">#6259</a>: docs: Correct typo and improve sentence structure in docs for <code>output.experimentalMinChunkSize</code> (<a href="https://github.com/millerick"><code>@​millerick</code></a>, <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6260">#6260</a>: fix(deps): update rust crate swc_compiler_base to v47 (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6261">#6261</a>: fix(deps): lock file maintenance minor/patch updates (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6262">#6262</a>: Avoid unnecessary cloning of the code string (<a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6263">#6263</a>: fix(deps): update minor/patch updates (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6265">#6265</a>: chore(deps): lock file maintenance (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6267">#6267</a>: fix(deps): update minor/patch updates (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6268">#6268</a>: chore(deps): update dependency eslint-plugin-unicorn to v63 (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6269">#6269</a>: chore(deps): update dependency lru-cache to v11 (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6270">#6270</a>: chore(deps): lock file maintenance (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6272">#6272</a>: forward NO_SIDE_EFFECTS annotations to function expressions in variable declarations (<a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> </ul> <h2>4.57.1</h2> <p><em>2026-01-30</em></p> <h3>Bug Fixes</h3> <ul> <li>Fix heap corruption issue in Windows (<a href="https://redirect.github.com/rollup/rollup/issues/6251">#6251</a>)</li> <li>Ensure exports of a dynamic import are fully included when called from a try...catch (<a href="https://redirect.github.com/rollup/rollup/issues/6254">#6254</a>)</li> </ul> <h3>Pull Requests</h3> <ul> <li><a href="https://redirect.github.com/rollup/rollup/pull/6251">#6251</a>: fix: Isolate and cache <code>process.report.getReport()</code> calls in a child process for robust environment detection (<a href="https://github.com/alan-agius4"><code>@​alan-agius4</code></a>, <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6252">#6252</a>: chore(deps): update dependency lru-cache to v11 (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot])</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6253">#6253</a>: chore(deps): lock file maintenance minor/patch updates (<a href="https://github.com/renovate"><code>@​renovate</code></a>[bot], <a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> <li><a href="https://redirect.github.com/rollup/rollup/pull/6254">#6254</a>: Fully include dynamic imports in a try-catch (<a href="https://github.com/lukastaegert"><code>@​lukastaegert</code></a>)</li> </ul> <!-- raw HTML omitted --> </blockquote> <p>... (truncated)</p> </details> <details> <summary>Commits</summary> <ul> <li><a href="ae846957f1"><code>ae84695</code></a> 4.59.0</li> <li><a href="b39616e917"><code>b39616e</code></a> Update audit-resolve</li> <li><a href="c60770d7aa"><code>c60770d</code></a> Validate bundle stays within output dir (<a href="https://redirect.github.com/rollup/rollup/issues/6275">#6275</a>)</li> <li><a href="33f39c1f20"><code>33f39c1</code></a> 4.58.0</li> <li><a href="b61c40803b"><code>b61c408</code></a> forward NO_SIDE_EFFECTS annotations to function expressions in variable decla...</li> <li><a href="7f00689ec9"><code>7f00689</code></a> Extend agent instructions</li> <li><a href="e7b2b85af0"><code>e7b2b85</code></a> chore(deps): lock file maintenance (<a href="https://redirect.github.com/rollup/rollup/issues/6270">#6270</a>)</li> <li><a href="2aa5da9baf"><code>2aa5da9</code></a> fix(deps): update minor/patch updates (<a href="https://redirect.github.com/rollup/rollup/issues/6267">#6267</a>)</li> <li><a href="4319837c54"><code>4319837</code></a> chore(deps): update dependency lru-cache to v11 (<a href="https://redirect.github.com/rollup/rollup/issues/6269">#6269</a>)</li> <li><a href="c3b6b4bdc4"><code>c3b6b4b</code></a> chore(deps): update dependency eslint-plugin-unicorn to v63 (<a href="https://redirect.github.com/rollup/rollup/issues/6268">#6268</a>)</li> <li>Additional commits viewable in <a href="https://github.com/rollup/rollup/compare/v4.52.5...v4.59.0">compare view</a></li> </ul> </details> <details> <summary>Install script changes</summary> <p>This version modifies <code>prepare</code> script that runs during installation. Review the package contents before updating.</p> </details> <br /> [](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores) Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`. [//]: # (dependabot-automerge-start) [//]: # (dependabot-automerge-end) --- <details> <summary>Dependabot commands and options</summary> <br /> You can trigger Dependabot actions by commenting on this PR: - `@dependabot rebase` will rebase this PR - `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it - `@dependabot show <dependency name> ignore conditions` will show all of the ignore conditions of the specified dependency - `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself) - `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself) - `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself) You can disable automated security fix PRs for this repo from the [Security Alerts page](https://github.com/sveltejs/svelte/network/alerts). </details> Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>	4 days ago
Mathias Picker	efb651cd33	perf: optimize parser hot paths for ~18% faster compilation (#17811) ... ## Summary Optimizes the Svelte compiler's parser phase — the hot path that runs on every file compilation during development (HMR). The changes are surgical micro-optimizations to 7 files in `packages/svelte/src/compiler/phases/1-parse/`, with no architectural changes. ### Changes - **`Parser.match()` — `slice` → `startsWith`**: Avoids creating a new substring on every multi-char match call (called thousands of times per compilation) - **`Parser.match_regex()` — `slice` → sticky flag**: Uses `lastIndex` + `y` flag instead of slicing the entire template string on every regex match. All 14 regex patterns passed to `match_regex`/`read` across 4 files updated with `y` flag. - **`Parser.allow_whitespace()` / `require_whitespace()` — regex → charCode**: Replaces `regex_whitespace.test()` with numeric charCode comparisons in a tight loop (called hundreds of times per compilation). Covers the full `\s` character set with a fast path for common ASCII whitespace. - **Text parser — string concatenation → `slice`**: Replaced `data += template[index++]` loop (O(n²)) with tracking start position + single `slice()` call (O(n)) - **`read_sequence` — string concatenation → `slice`**: Same pattern — derive `raw` from `template.slice()` in `flush()` instead of char-by-char concatenation - **`is_valid_element_name()` — inline regexes → module-level constants**: Extracted 2 regex literals to module scope - **Dynamic `new RegExp()` → `indexOf`**: Replaced `parser.read_until(new RegExp(...))` with `template.indexOf()` for script/style closing tags - **`match_bracket` — `Array.includes` → `Set.has`**: Pre-computes close bracket values as a `Set` for O(1) lookups ## Benchmark A benchmark script was written that: 1. Compiles 5 real test components of varying complexity (a11y validators, form bindings, component migration output, rich selects) 2. Compiles 2 synthetic stress-test templates (500 elements and 2000 elements with expressions and entities) 3. Runs 50 warmup iterations for parse, 20 for compile (JIT warmup) 4. Forces GC between benchmarks via `--expose-gc` 5. Measures both parse-only and full compilation (parse + analyze + transform + codegen) ### Parse-only results | Component | Before | After | Speedup | |---|---|---|---| | a11y-role-supports-aria-props (371 lines) | 2.410ms | 2.129ms | **-11.7%** | | form-default-value-spread (199 lines) | 1.726ms | 1.360ms | **-21.2%** | | svelte-component (251 lines) | 1.925ms | 1.648ms | **-14.4%** | | select-with-rich-content (157 lines) | 0.795ms | 0.636ms | **-20.0%** | | rich-select (173 lines) | 0.807ms | 0.637ms | **-21.1%** | | synthetic-large (500 elements) | 2.560ms | 1.547ms | **-39.6%** | | synthetic-huge (2000 elements) | 136.849ms | 114.115ms | **-16.6%** | | **Total** | **147.071ms** | **122.072ms** | **-17.0%** | ### Full compile results | Component | Before | After | Speedup | |---|---|---|---| | a11y-role-supports-aria-props | 25.407ms | 21.990ms | **-13.4%** | | form-default-value-spread | 10.711ms | 9.422ms | **-12.0%** | | svelte-component | 10.304ms | 8.481ms | **-17.7%** | | select-with-rich-content | 5.986ms | 4.694ms | **-21.6%** | | rich-select | 6.010ms | 5.059ms | **-15.8%** | | synthetic-large (500 elements) | 30.511ms | 25.196ms | **-17.4%** | | synthetic-huge (2000 elements) | 932.801ms | 764.794ms | **-18.0%** | | **Total** | **1021.729ms** | **839.637ms** | **-17.8%** | Benchmarked on macOS, Node.js, Apple Silicon. The parse improvements carry through to end-to-end compile time since the parser is a significant portion of the compilation pipeline. Text-heavy templates benefit the most (up to 40% faster parse). Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>	4 days ago
Rich Harris	dd5b587bd3	chore: simplify batch.flush (#17814) ... 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`	4 days ago
Rich Harris	5e28508377	chore: simplify create effect (#17813) ... 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`	4 days ago
Rich Harris	5bd4699539	chore: more efficient effect scheduling (#17808) ... 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.	4 days ago
Rich Harris	b76cd5cafc	chore: null out current_batch before committing branches (#17809) ... 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`	4 days ago
Elliott Johnson	fa4f1c45f4	chore: run `prettier` (#17803) ... Just fixing CI 🙄	5 days ago
github-actions[bot]	ed14b499d6	Version Packages (#17802) ... 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>	5 days ago
Paolo Ricciuti	0df5abcae2	Merge commit from fork ... * fix: escape `innerText` and `textContent` bindings of `contenteditable` * fix: better if else structure	5 days ago
Elliott Johnson	0298e97937	Merge commit from fork ... * fix: sanitize `transformError` values prior to embedding in HTML comments * did a little dumb	5 days ago
github-actions[bot]	96fd3ce763	Version Packages (#17786) ... 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@5.53.4 ### Patch Changes - fix: set server context after async transformError ([#17799](https://github.com/sveltejs/svelte/pull/17799)) - fix: hydrate if blocks correctly ([#17784](https://github.com/sveltejs/svelte/pull/17784)) - fix: handle default parameters scope leaks ([#17788](https://github.com/sveltejs/svelte/pull/17788)) - fix: prevent flushed effects from running again ([#17787](https://github.com/sveltejs/svelte/pull/17787)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>	5 days ago
Simon H	1b3e660519	fix: prevent flushed effects from running again (#17787) ... 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.	5 days ago
Elliott Johnson	f6e8b1d11e	chore: require pr number as input when manually invoking pkg.pr.new (#17797)	6 days ago
Simon H	673a1ab964	fix: set server context after async transformError (#17799) ... This will get the tests in https://github.com/sveltejs/kit/pull/15308 green, right now they fail because page state cannot be found because context not available	6 days ago
Maurício Kishi	3a289797bd	fix: handle default parameters scope leaks (#17788) ... 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`	6 days ago
Elliott Johnson	fef7e0f742	chore: remove ecosystem-ci-gate workflow (#17795) ... The app shared between Kit and Svelte takes care of this now ### 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`	6 days ago
Simon H	fcdc0289db	fix: hydrate if blocks correctly (#17784) ... We were not using the correct node to analyze the if block marker Fixes #17751	1 week ago
github-actions[bot]	97f3ac5571	Version Packages (#17775) ... 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>	1 week ago
Simon H	d444e29907	chore: robustify ecosystem gate script (#17781) ... - pull_request should be enough (pull_request_target exposes more stuff) - trigger the full run less often	1 week ago
Simon H	8566b7a63b	chore: require `/ecosystem-ci` run in "Version packages" PR (#17780) ... let's see if this works	1 week ago
Andre Hora	9360563c94	docs: remove reference to archived https://github.com/sveltejs/template (#17779) ... Repository https://github.com/sveltejs/template is archived and no longer maintained. ### 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` --------- Co-authored-by: Rich Harris <hello@rich-harris.dev>	1 week ago
Simon H	7deedc5bb4	fix: render `:catch` of `#await` block with correct key (#17769) ... Fixes #17678	1 week ago
Ben McCann	8334abd626	chore: cleanup eslint peer dependencies (#17757)	1 week ago
Paolo Ricciuti	f67d03df5b	fix: make string coercion consistent to `toString` (#17774) ... 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`	1 week ago