Skip to content

fix: don't warn about removed SSI comments in transformPageChunk#15695

Merged
elliott-with-the-longest-name-on-github merged 2 commits into
sveltejs:mainfrom
aubergene:fix/ssi-comment-transform-warning
Apr 22, 2026
Merged

fix: don't warn about removed SSI comments in transformPageChunk#15695
elliott-with-the-longest-name-on-github merged 2 commits into
sveltejs:mainfrom
aubergene:fix/ssi-comment-transform-warning

Conversation

@aubergene

@aubergene aubergene commented Apr 10, 2026

Copy link
Copy Markdown
Contributor

Problem

When using server-side includes (SSI) — HTML comment directives like <!--#include virtual="/header.html" --> that are replaced by servers such as nginx — removing them in transformPageChunk triggers a false positive warning:

Removing comments in transformPageChunk can break Svelte's hydration

SSI directives are intentionally removed/replaced by the server and have nothing to do with Svelte's hydration mechanism.

Fix

Svelte's hydration comments (<!--[-->, <!--]-->, <!---->, etc.) never start with <!--#. SSI directives always start with <!--#. Using a negative lookahead regex (<!--(?!#)) to count only non-SSI comments means:

  • Removing SSI comments in transformPageChunk → no warning
  • Removing actual Svelte hydration comments → warning still fires correctly

Changesets

  • Patch changeset added for @sveltejs/kit

Tests

  • All existing unit tests pass (pnpm -F @sveltejs/kit test:unit)
  • The warning logic is DEV-only and exercised through integration tests; no new unit test added as the fix is a one-liner regex change

Please don't delete this checklist! 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
  • This message body should clearly illustrate what problems it solves.
  • Ideally, include a test that fails without this PR but passes with it.

Tests

  • Run the tests with pnpm test and lint the project with pnpm lint and pnpm check

Changesets

  • If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running pnpm changeset and following the prompts. Changesets that add features should be minor and those that fix bugs should be patch. Please prefix changeset messages with feat:, fix:, or chore:.

Edits

  • Please ensure that 'Allow edits from maintainers' is checked. PRs without this option may be closed.

@changeset-bot

changeset-bot Bot commented Apr 10, 2026 •
edited
Loading

Copy link
Copy Markdown

🦋 Changeset detected

Latest commit: e64fbf9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package
Name Type
@sveltejs/kit Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

@svelte-docs-bot

svelte-docs-bot Bot commented Apr 10, 2026

Copy link
Copy Markdown

Preview: https://svelte-dev-git-preview-kit-15695-svelte.vercel.app/

@aubergene aubergene force-pushed the fix/ssi-comment-transform-warning branch from bcbd43a to 2be155b Compare April 10, 2026 12:07
elliott-with-the-longest-name-on-github
elliott-with-the-longest-name-on-github reviewed Apr 21, 2026
View reviewed changes

@elliott-with-the-longest-name-on-github elliott-with-the-longest-name-on-github left a comment

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Let's hoist this function, but other than that lgtm

Comment thread packages/kit/src/runtime/server/page/render.js Outdated
aubergene and others added 2 commits April 22, 2026 11:23
@aubergene @claude
fix: don't warn about removed SSI comments in transformPageChunk
3ee88c2 
Server-side include directives (e.g. <!--#include virtual="..." -->) look
like HTML comments but are replaced by servers such as nginx. Removing them
in transformPageChunk triggered a false positive warning about breaking
Svelte's hydration.

Svelte's hydration comments never start with <!--#, so SSI directives can
be safely excluded from the check using a negative lookahead regex.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
@aubergene @claude
refactor: hoist count_non_ssi_comments into server utils
e64fbf9 
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
@aubergene aubergene force-pushed the fix/ssi-comment-transform-warning branch from 5f5d98b to e64fbf9 Compare April 22, 2026 10:23
@elliott-with-the-longest-name-on-github elliott-with-the-longest-name-on-github merged commit 8cc203a into sveltejs:main Apr 22, 2026
25 checks passed
This was referenced Apr 21, 2026
Merged
Merged
elliott-with-the-longest-name-on-github pushed a commit that referenced this pull request Apr 23, 2026
@github-actions
Version Packages (#15716)
a21582c 
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
## @sveltejs/kit@2.58.0

### Minor Changes

- breaking: require `limit` in `requested` (as originally intended)
([#15739](#15739))


- feat: `RemoteQueryFunction` gains an optional third generic parameter
`Validated` (defaulting to `Input`) that represents the argument type
after schema validation/transformation
([#15739](#15739))


- breaking: `requested` now yields `{ arg, query }` entries instead of
the validated argument
([#15739](#15739))

### Patch Changes

- fix: allow `query().current`, `.error`, `.loading`, and `.ready` to
work in non-reactive contexts
([#15699](#15699))


- fix: prevent `deep_set` crash on nullish nested values
([#15600](#15600))


- fix: restore correct `RemoteFormFields` typing for nullable array
fields (e.g. when a schema uses `.default([])`), so `.as('checkbox')`
and friends work again
([#15723](#15723))


- fix: don't warn about removed SSI comments in `transformPageChunk`
([#15695](#15695))

Server-side include (SSI) directives like `<!--#include virtual="..."
-->` are HTML comments that are replaced by servers such as nginx.
Previously, removing them in `transformPageChunk` would trigger a false
positive warning about breaking Svelte's hydration. Since SSI comments
always start with `<!--#` and Svelte's hydration comments never do, they
can be safely excluded from the check.

- Change enhance function return type from void to MaybePromise<void>.
([#15710](#15710))


- fix: throw an error when `resolve` is called with an external URL
([#15733](#15733))


- fix: avoid FOUC for CSR-only pages by loading styles and fonts before
CSR starts ([#15718](#15718))


- fix: reset form result on redirect
([#15724](#15724))

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@elliott-with-the-longest-name-on-github elliott-with-the-longest-name-on-github elliott-with-the-longest-name-on-github approved these changes

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

2 participants

@aubergene @elliott-with-the-longest-name-on-github