fix: stop emitting null block metadata defaults that @deepnote/blocks rejects on save

[sLightlyDev]

Problem

The local Zod schemas in deepnoteSchemas.ts produce the metadata for newly-created blocks. That metadata is handed straight back to @deepnote/blocks on save, and its block schema rejects an explicit null on optional fields. Two fields defaulted to null, so the blocks they belong to could not be saved at all:

Block	Field	Default before
Input Select	deepnote_variable_select_type	null
Input File	deepnote_allowed_file_extensions	null

Verified against serializeDeepnoteFile from @deepnote/blocks@4.6.0:

REJECTED input-select  -> deepnote_variable_select_type: Expected 'from-options' | 'from-variable', received null
REJECTED input-file    -> deepnote_allowed_file_extensions: Expected string, received null

deepnote_variable_default_value also defaults to null in several schemas, but the package explicitly coerces null → undefined for that one field, so it is fine.

Fix

• deepnote_variable_select_type defaults to 'from-options'.
• deepnote_allowed_file_extensions defaults to undefined rather than null, matching the package's optional-string field. Both consumers (deepnoteInputBlockCellStatusBarProvider.ts:556,933) already read it as string | undefined behind a falsy guard, so behavior is unchanged.

Tests

Rather than testing the two instances, this covers the class. getInputBlockMetadata now has one test per entry in INPUT_BLOCK_TYPES asserting that its default metadata survives serializeDeepnoteFile. Any future drift between the local schemas and the package fails at that boundary instead of at a user's save.

The block under test is built with createBlockFromPocket, so the test runs the same cell-to-block path used on save rather than a hand-assembled approximation.

Both new failures were confirmed against the pre-fix schema, each for the expected reason:

1) getInputBlockMetadata default input-select metadata is accepted by the @deepnote/blocks serializer
   expected [Function] to not throw but '{"expected": "'from-options'|'from-variable'", received: null}' was thrown
2) getInputBlockMetadata default input-file metadata is accepted by the @deepnote/blocks serializer
   expected [Function] to not throw but '{"code": "invalid_type", received: null}' was thrown

Full unit suite: 2634 passing, 0 failing. Typecheck, lint and compile-tsc clean.

expectedMetadataKeys for input-file drops deepnote_allowed_file_extensions — that assertion was pinning the unsaveable output.

The round-trip/escaping test from the first revision was removed: it hardcoded select_type, so it passed with and without the fix, and the escaping behavior it described is already covered by the InputSelectBlockConverter suite.

Follow-up (not in this PR)

The root cause is that deepnoteSchemas.ts re-declares block metadata that @deepnote/blocks also declares, and the two drift. The package does not currently export its per-block schemas (only the deepnoteBlockSchema union), and it pins zod 3.25.76 while this repo is on zod 4.x — so the schemas cannot simply be imported and reused today.

Worth noting separately: getInputBlockMetadata's return type is not correlated with its blockType argument, so it returns a union of all nine metadata shapes. Correlating them would let callers construct a DeepnoteBlock without a cast.

Summary by CodeRabbit

• Bug Fixes

  • Improved handling of missing Deepnote variable selection and allowed file extension settings.
  • Ensured omitted file extension metadata is represented consistently.

• Tests

  • Expanded coverage to verify all supported input block types serialize correctly with default metadata.

[coderabbitai]

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ℹ️ Recent review info

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Reviewing files that changed from the base of the PR and between 64d9656 and 8df4516.

📒 Files selected for processing (2)

• src/notebooks/deepnote/deepnoteNotebookCommandListener.unit.test.ts
• src/notebooks/deepnote/deepnoteSchemas.ts

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• src/notebooks/deepnote/deepnoteSchemas.ts

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📝 Walkthrough

Walkthrough

The schema restores the deepnote_variable_select_type fallback to from-options and maps nullish deepnote_allowed_file_extensions values to undefined. Tests add Deepnote serialization helpers and parameterized coverage for every input block type. Input-file metadata expectations now omit deepnote_allowed_file_extensions.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 8df45

The change replaces rejected null metadata defaults with serializer-compatible values, preventing save failures for affected input blocks. No actionable merge-blocking risk remains after normal checks and review.

Possibly related PRs

• deepnote/vscode-deepnote#17: Updates Deepnote schema handling and serialization behavior.
• deepnote/vscode-deepnote#22: Expands Deepnote block types and serialization shapes.
• deepnote/vscode-deepnote#60: Updates Deepnote block conversion and serialization tests.

Suggested reviewers: tkislan, mfranczel, dinohamzic

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Updates Docs	❓ Inconclusive	The PR diff contains only schema and test changes; no documentation files changed, and the public/private Deepnote repositories are unavailable here.	Please verify or update the deepnote/deepnote OSS documentation and the deepnote-internal landing-page roadmap.

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the fix: preventing null block metadata defaults that Deepnote rejects during save.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0%. Comparing base (aff145f) to head (8df4516).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@     Coverage Diff     @@
##   main   #407   +/-   ##
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