mod: add local module replacement support with robust path resolution #4214
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Add support for local path replacements in module.cue files, similar to Go's replace directive. This allows replacing module dependencies with local directories using paths like "./local-dep" or "../sibling". Key changes: - Add modreplace package for handling local path replacements - Add localreg.go to wrap Registry with replacement support - Update schema.cue to allow empty version for replace-only deps - Compute absolute paths at creation time instead of using os.Getwd() - Add comprehensive tests including script tests for various scenarios The path resolution now requires either: - A filesystem implementing module.OSRootFS, or - An absolute directory path This eliminates fragile reliance on os.Getwd() which could fail in containers, tests, or when the working directory changes. Signed-off-by: David Flanagan <[email protected]>
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Pull request overview
This PR adds support for local module path replacements similar to Go's replace directive, allowing CUE modules to replace dependencies with local directories using paths like "./local-dep" or "../sibling". The implementation includes robust path resolution that avoids reliance on os.Getwd() by computing absolute paths at creation time.
Key changes:
- Introduces the modreplace package to handle local path replacement resolution and validation
- Adds localReplacementRegistry wrapper to intercept module fetches and requirements for replaced modules
- Updates schema.cue to support the replace field in dependencies and allow empty versions for replace-only deps
- Threads replacement maps through all Requirements creation and tidy operations
Reviewed changes
Copilot reviewed 21 out of 21 changed files in this pull request and generated 7 comments.
Show a summary per file
| File | Description |
|---|---|
| mod/modfile/schema.cue | Adds replace field to #Dep, allows empty version strings, and restricts local path replacements in strict mode |
| internal/mod/modfiledata/modfile.go | Implements Replacement struct and parseReplacement function to parse both local and remote replacements |
| internal/mod/modreplace/local.go | Core logic for resolving local paths to absolute paths and fetching module info from local directories |
| internal/mod/modreplace/local_test.go | Comprehensive unit tests for local replacement path resolution and error handling |
| internal/mod/modload/localreg.go | Registry wrapper that intercepts fetch/requirements calls to handle replacements |
| internal/mod/modrequirements/requirements.go | Adds replacement tracking to Requirements struct and applies remote replacements in cueModSummary |
| internal/mod/modrequirements/requirements_test.go | Updates test calls to include nil replacement parameter |
| internal/mod/modload/tidy.go | Preserves replace directives during tidy, adds replacement equality checking |
| internal/mod/modload/update.go | Threads replacements through UpdateVersions operations |
| cue/load/instances.go | Updates package loading to use wrapped registry with replacement support |
| internal/mod/modpkgload/pkgload_test.go | Updates test to pass nil replacements |
| internal/mod/modpkgload/import.go | Adds comment about registry handling replacements |
| internal/lsp/cache/module.go | Updates LSP module loading to pass replacements to Requirements |
| cmd/cue/cmd/modtidy.go | Changes to use module.OSDirFS for OSRootFS support |
| cue/load/loader_test.go | Updates expected line number in error message due to schema changes |
| cmd/cue/cmd/testdata/script/modreplace_*.txtar | Six new script tests covering local, remote, sibling, nested, missing, and command scenarios |
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Address feedback from PR cue-lang#4214 review: - Fix misleading comment in requirements.go about local path replacement handling (local replacements are handled by localReplacementRegistry wrapper, not in cueModSummary) - Clarify schema.cue documentation: use "version-independent replacement" instead of "version is unknown" - Use module.Version.Equal() method instead of != operator in tidy.go for idiomatic comparison - Add clarifying comment explaining intentional orphan replacement preservation (matches Go's go mod tidy behavior) - Add explicit validation rejecting absolute paths in parseReplacement() with clear error messages for both Unix and Windows paths - Add test for self-referencing local replacements to verify the system handles edge cases gracefully
Address feedback from PR cue-lang#4214 review: - Fix misleading comment in requirements.go about local path replacement handling (local replacements are handled by localReplacementRegistry wrapper, not in cueModSummary) - Clarify schema.cue documentation: use "version-independent replacement" instead of "version is unknown" - Use module.Version.Equal() method instead of != operator in tidy.go for idiomatic comparison - Add clarifying comment explaining intentional orphan replacement preservation (matches Go's go mod tidy behavior) - Add explicit validation rejecting absolute paths in parseReplacement() with clear error messages for both Unix and Windows paths - Add test for self-referencing local replacements to verify the system handles edge cases gracefully Signed-off-by: David Flanagan <[email protected]>
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Pull request overview
Copilot reviewed 21 out of 21 changed files in this pull request and generated 4 comments.
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Address remaining PR cue-lang#4214 review feedback: - Improve Windows drive letter validation to verify the first character is actually a letter using unicode.IsLetter() (fixes false positives on paths like "9:\notpath") - Add UNC path rejection for \\server\share and //server/share paths - Add comprehensive unit tests for parseReplacement() covering valid local/remote paths, absolute path rejection, UNC paths, strict mode, and invalid module paths/versions - Add script test verifying replace directives are preserved when dependencies are removed during tidy Signed-off-by: David Flanagan <[email protected]>
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Pull request overview
Copilot reviewed 23 out of 23 changed files in this pull request and generated no new comments.
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Add support for local path replacements in module.cue files, similar to Go's replace directive. This allows replacing module dependencies with local directories using paths like "./local-dep" or "../sibling".
First pass at #2956
Key changes:
The path resolution now requires either:
This eliminates fragile reliance on os.Getwd() which could fail in containers, tests, or when the working directory changes.