fix(cli): vtt style region blocks

[AndreyHirsa]

Summary

Fix VTT parser crash when files contain STYLE or REGION blocks, which are valid WebVTT features unsupported by the node-webvtt library.

Changes

• Extract STYLE/REGION blocks before passing VTT content to node-webvtt parser
• Re-insert STYLE/REGION blocks into translated output after the WEBVTT header

Testing

Business logic tests added:

• STYLE block is stripped during pull and cues are parsed correctly
• STYLE block is preserved in push output alongside translated cues
• REGION block is stripped during pull and cues are parsed correctly
• REGION block is preserved in push output alongside translated cues
• All tests pass locally

Visuals

N/A — no UI changes.

Checklist

• Changeset added (if version bump needed)
• Tests cover business logic (not just happy path)
• No breaking changes (or documented below)

Summary by CodeRabbit

• Bug Fixes

  • Fixed a VTT parser crash for files containing STYLE or REGION blocks; non-cue blocks are now handled and preserved through import/export.

• Tests

  • Added tests verifying pull ignores non-cue blocks and push preserves STYLE/REGION content while updating cue text.

• Chores

  • Added a changeset recording a patch release for the VTT fix.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 2f965e6f-d25d-4c5b-b35d-260950d49f2a

📥 Commits

Reviewing files that changed from the base of the PR and between a7ebd61 and 48495d7.

📒 Files selected for processing (1)

• packages/cli/src/cli/loaders/vtt.ts

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📝 Walkthrough

Walkthrough

Added a changeset and updated the VTT loader to strip STYLE/REGION blocks during pull() and preserve/reinsert them after the WEBVTT header during push() (push signature now accepts an originalInput third parameter). Tests added for extraction and preservation behavior.

Changes

Cohort / File(s)	Summary
Changeset .changeset/violet-pens-build.md	New patch changeset noting a fix for a VTT parser crash when STYLE/REGION blocks are present.
VTT Loader Implementation packages/cli/src/cli/loaders/vtt.ts	Added helpers to detect and extract STYLE/REGION blocks, normalize line endings, and split by blank-line blocks. pull() strips unsupported blocks before parsing; push(locale, payload, originalInput) can reinsert original STYLE/REGION blocks immediately after the WEBVTT header. (Push signature updated.)
VTT Loader Tests packages/cli/src/cli/loaders/index.spec.ts	Added four tests verifying pull() ignores STYLE/REGION (returns only cue entries) and push() preserves original STYLE/REGION blocks while applying updated cue texts.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Suggested reviewers

• vrcprl

Poem

🐇 I found the VTT with regions and style,
They tangled the parser and lingered awhile.
I nibbled them out, kept each cue in its place,
Then stitched them back neat, right after the base.
Hooray — the captions now hop with grace!

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'fix(cli): vtt style region blocks' is concise and directly related to the main change: fixing VTT parser crashes caused by STYLE/REGION blocks.
Description check	✅ Passed	The PR description matches the template structure with complete Summary, Changes, Testing, Visuals, and Checklist sections. All required business logic tests are documented with checkboxes marked.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/vtt-style-region-blocks

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@packages/cli/src/cli/loaders/vtt.ts`:
- Around line 33-42: The loader currently uses a single module-level savedBlocks
array that is overwritten in pull(), causing cross-locale leakage; update the
implementation in createLoader's pull/push logic to keep extracted blocks
per-locale (keyed by the locale argument) or re-derive blocks from the
locale-specific pullInput available in push(), using
extractUnsupportedBlocks(input) for that locale instead of the shared
savedBlocks; update both places that read/write savedBlocks (the pull()
assignment where savedBlocks = blocks and the later code that consumes
savedBlocks) to use the per-locale map or to compute blocks from the pullInput
passed to push().
- Around line 14-19: The unsupportedRegex currently matches prefixes like
"STYLE" or "REGION" and thus incorrectly strips cues such as "REGION42" or
"STYLE_intro"; update the check in the loop that examines firstLine by trimming
trailing whitespace (use trim() or trimEnd()) and change unsupportedRegex to
anchor the end of the line (e.g., /^(?:STYLE|REGION)\s*$/) so it only matches
exact header lines; adjust the test in the for-loop that uses
unsupportedRegex.test(firstLine) accordingly (see unsupportedRegex and the loop
over parts / firstLine).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 05ec2afc-11d8-40b6-a0f6-b6a241c7f463

📥 Commits

Reviewing files that changed from the base of the PR and between d18be81 and bb15da3.

📒 Files selected for processing (3)

• .changeset/violet-pens-build.md
• packages/cli/src/cli/loaders/index.spec.ts
• packages/cli/src/cli/loaders/vtt.ts