feat(extensions): support .extensionignore to exclude files during install by Rubiss · Pull Request #1781 · github/spec-kit

Rubiss · 2026-03-09T04:45:01Z

Summary

Adds .extensionignore support so extension authors can exclude files and folders from being copied when users run specify extension add.

Problem

Extension authors often have development-only files (tests, CI configs, documentation source, build artifacts) that shouldn't be copied into the user's project when installing an extension. There was no mechanism to exclude these files.

Solution

Extension authors can now create a .extensionignore file in their extension root. The file uses .gitignore-compatible patterns (one per line), powered by the pathspec library:

# .extensionignore

# Development files
tests/
.github/
.gitignore

# Build artifacts
__pycache__/
*.pyc

Features

.gitignore-compatible pattern matching via pathspec.GitIgnoreSpec
* matches anything except /; ** matches zero or more directories
? matches any single character except /
Trailing / on directory patterns restricts matching to directories only
Patterns containing / (other than trailing) are anchored to the extension root
! negates a previously excluded pattern (re-includes a file)
Comment lines (#) and blank lines are ignored
Backslash patterns are normalised to forward slashes for cross-platform compatibility
The .extensionignore file itself is always excluded from the copy

Changes

src/specify_cli/extensions.py: Added _load_extensionignore() static method and integrated it into install_from_directory() via shutil.copytree(ignore=...)
extensions/EXTENSION-DEVELOPMENT-GUIDE.md: New documentation section covering .extensionignore format, example patterns, and a pattern-matching reference table
tests/test_extensions.py: 13 new tests in TestExtensionIgnore covering all pattern matching scenarios
pyproject.toml: Added pathspec>=0.12.0 dependency
CHANGELOG.md: Added [Unreleased] entry for this feature

Testing

All 152 passing tests continue to pass (4 pre-existing failures in test_cursor_frontmatter.py are unrelated — bash/WSL not available on Windows). New tests cover:

No .extensionignore → all files copied (baseline)
Directory exclusion (tests/, .github/)
Glob patterns (*.pyc) across nested directories
Comments and blank lines ignored
.extensionignore itself never copied
Relative path pattern matching
.. traversal patterns are a no-op (security)
Absolute path patterns are a no-op (security)
Empty .extensionignore file
Windows backslash patterns normalised correctly
* does not cross directory boundaries
** crosses directory boundaries
! negation re-includes previously excluded files

AI Disclosure

This PR was authored with GitHub Copilot assistance.

Copilot

Pull request overview

This PR adds .extensionignore support to the extension installation pipeline, letting extension authors exclude development-only files (tests, CI configs, docs source, build artifacts) from being copied when users run specify extension add. The feature is analogous to .gitignore and is integrated into ExtensionManager.install_from_directory() via a new _load_extensionignore() static method.

Changes:

Added _load_extensionignore() static method to ExtensionManager and wired it into install_from_directory() via shutil.copytree(ignore=…)
Added 6 new test cases in TestExtensionIgnore covering all documented scenarios
Added documentation section in EXTENSION-DEVELOPMENT-GUIDE.md and bumped version to 0.1.14

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
`src/specify_cli/extensions.py`	New `_load_extensionignore()` static method; integrates ignore function into `install_from_directory()`; adds `Callable`/`Set` and `fnmatch` imports
`tests/test_extensions.py`	6 new tests in `TestExtensionIgnore` class covering all pattern-matching scenarios
`extensions/EXTENSION-DEVELOPMENT-GUIDE.md`	New "Excluding Files with `.extensionignore`" section with format description, example, and pattern table
`CHANGELOG.md`	New 0.1.14 entry documenting the feature
`pyproject.toml`	Version bump from 0.1.13 to 0.1.14

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CHANGELOG.md

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

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extensions/EXTENSION-DEVELOPMENT-GUIDE.md

mnriem

I will approve, but consider the things below

fnmatch ≠ .gitignore semantics (documentation bug)
The docs and PR description claim "similar to .gitignore syntax," but fnmatch.fnmatch() treats * as matching any character including path separators. In .gitignore, * does not cross directory boundaries. The documentation table says docs/*.draft.md matches "Draft markdown files inside docs/", but fnmatch would also match docs/sub/api.draft.md. This needs to either:
- Switch to pathlib.PurePath.match() or fnmatch with per-segment matching to get proper gitignore-like behavior, or
- Remove all .gitignore comparisons from the docs and clearly document that * matches across directories.
No support for negation (!) or ** patterns
Not a blocker since these aren't claimed, but the .gitignore analogy sets expectations. At minimum, the docs should state what's not supported.
Missing edge-case tests:
- Pattern with .. (e.g., ../sibling/) — should be a no-op or explicitly rejected
- Absolute path patterns (e.g., /etc/passwd) — verify they don't match anything
- Empty .extensionignore file (no patterns, just the file itself)
- Patterns with Windows-style backslashes
Minor: forward-slash normalization is one-directional
The code does rel_path_fwd = rel_path.replace("\\", "/") but doesn't normalize the patterns themselves. A user on Windows writing docs\internal\draft.md in their .extensionignore would get inconsistent behavior.

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Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

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Rubiss · 2026-03-09T15:15:00Z

I will approve, but consider the things below

fnmatch ≠ .gitignore semantics (documentation bug)
The docs and PR description claim "similar to .gitignore syntax," but fnmatch.fnmatch() treats * as matching any character including path separators. In .gitignore, * does not cross directory boundaries. The documentation table says docs/*.draft.md matches "Draft markdown files inside docs/", but fnmatch would also match docs/sub/api.draft.md. This needs to either:

Switch to pathlib.PurePath.match() or fnmatch with per-segment matching to get proper gitignore-like behavior, or

Remove all .gitignore comparisons from the docs and clearly document that * matches across directories.

No support for negation (!) or ** patterns
Not a blocker since these aren't claimed, but the .gitignore analogy sets expectations. At minimum, the docs should state what's not supported.

Missing edge-case tests:

Pattern with .. (e.g., ../sibling/) — should be a no-op or explicitly rejected

Absolute path patterns (e.g., /etc/passwd) — verify they don't match anything

Empty .extensionignore file (no patterns, just the file itself)

Patterns with Windows-style backslashes

Minor: forward-slash normalization is one-directional
The code does rel_path_fwd = rel_path.replace("\\", "/") but doesn't normalize the patterns themselves. A user on Windows writing docs\internal\draft.md in their .extensionignore would get inconsistent behavior.

No need to approve yet, these seem like all valid concerns that I will address. Thanks for the feedback. Personally, I think it should work consistently like .gitignore does since generally people are very familiar with the concept.

…stall Add .extensionignore support so extension authors can exclude files and folders from being copied when users run 'specify extension add'. The file uses glob-style patterns (one per line), supports comments (#), blank lines, trailing-slash directory patterns, and relative path matching. The .extensionignore file itself is always excluded from the copy. - Add _load_extensionignore() to ExtensionManager - Integrate ignore function into shutil.copytree in install_from_directory - Document .extensionignore in EXTENSION-DEVELOPMENT-GUIDE.md - Add 6 tests covering all pattern matching scenarios - Bump version to 0.1.14

…re matching Replace fnmatch with pathspec.GitIgnoreSpec to get proper .gitignore semantics where * does not cross directory boundaries. This addresses review feedback on github#1781. Changes: - Switch from fnmatch to pathspec>=0.12.0 (GitIgnoreSpec.from_lines) - Normalize backslashes in patterns for cross-platform compatibility - Distinguish directories from files for trailing-slash patterns - Update docs to accurately describe supported pattern semantics - Add edge-case tests: .., absolute paths, empty file, backslashes, * vs ** boundary behavior, and ! negation - Move changelog entry to [Unreleased] section

Rubiss · 2026-03-10T02:08:01Z

I will approve, but consider the things below

1. **`fnmatch` ≠ `.gitignore` semantics (documentation bug)**
   The docs and PR description claim "similar to `.gitignore` syntax," but `fnmatch.fnmatch()` treats `*` as matching **any** character including path separators. In `.gitignore`, `*` does **not** cross directory boundaries. The documentation table says `docs/*.draft.md` matches "Draft markdown files inside `docs/`", but `fnmatch` would also match `docs/sub/api.draft.md`. This needs to either:
   
   * Switch to `pathlib.PurePath.match()` or `fnmatch` with per-segment matching to get proper gitignore-like behavior, **or**
   * Remove all `.gitignore` comparisons from the docs and clearly document that `*` matches across directories.

2. **No support for negation (`!`) or `**` patterns**
   Not a blocker since these aren't claimed, but the `.gitignore` analogy sets expectations. At minimum, the docs should state what's **not** supported.

3. **Missing edge-case tests:**
   
   * Pattern with `..` (e.g., `../sibling/`) — should be a no-op or explicitly rejected
   * Absolute path patterns (e.g., `/etc/passwd`) — verify they don't match anything
   * Empty `.extensionignore` file (no patterns, just the file itself)
   * Patterns with Windows-style backslashes

4. **Minor: forward-slash normalization is one-directional**
   The code does `rel_path_fwd = rel_path.replace("\\", "/")` but doesn't normalize the patterns themselves. A user on Windows writing `docs\internal\draft.md` in their `.extensionignore` would get inconsistent behavior.

Thanks for the feedback. I have updated .extensionignore implementation to match familiar .gitignore patterns with a callout of what is not supported. Let me know what you think.

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

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pyproject.toml

extensions/EXTENSION-DEVELOPMENT-GUIDE.md

…re matching Replace fnmatch with pathspec.GitIgnoreSpec to get proper .gitignore semantics where * does not cross directory boundaries. This addresses review feedback on github#1781. Changes: - Switch from fnmatch to pathspec>=0.12.0 (GitIgnoreSpec.from_lines) - Normalize backslashes in patterns for cross-platform compatibility - Distinguish directories from files for trailing-slash patterns - Update docs to accurately describe supported pattern semantics - Add edge-case tests: .., absolute paths, empty file, backslashes, * vs ** boundary behavior, and ! negation - Move changelog entry to [Unreleased] section

Copilot

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Rubiss requested a review from mnriem as a code owner March 9, 2026 04:45

Copilot AI review requested due to automatic review settings March 9, 2026 04:45

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Rubiss force-pushed the feat/extensionignore-support branch from 0a00c97 to 5245079 Compare March 9, 2026 04:52

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Rubiss force-pushed the feat/extensionignore-support branch from 5245079 to 868d608 Compare March 9, 2026 13:52

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feat(extensions): support .extensionignore to exclude files during install#1781

feat(extensions): support .extensionignore to exclude files during install#1781
Rubiss wants to merge 2 commits intogithub:mainfrom
Rubiss:feat/extensionignore-support

Rubiss commented Mar 9, 2026 •

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Rubiss commented Mar 9, 2026 •

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