Add --prune option to remove defunct route files when OpenAPI spec changes

[Copilot]

When an OpenAPI spec renames a path parameter (e.g., {Name} → {nickname}), both the old and new route files coexist, creating wildcard ambiguity in ModuleTree resolution. The --prune flag removes route files that no longer exist in the spec before generating new ones.

Changes

• src/typescript-generator/prune.js — New pruneRoutes(destination, openApiPaths) function: walks routes/, deletes .ts files with no matching spec path, removes empty directories post-prune. _.context.ts files are always preserved.
• src/typescript-generator/generate.js — Calls pruneRoutes() when generateOptions.prune && generateOptions.routes, before writing new files.
• src/server/config.ts — Adds optional prune?: boolean to the generate config shape.
• src/typescript-generator/code-generator.ts — Updates constructor/field types to accept prune?.
• bin/counterfact.js — Adds --prune CLI flag wired into config.generate.prune.
• test/typescript-generator/prune.test.js — 7 tests covering file deletion, context file preservation, empty-dir cleanup, root path (/ → index.ts), no-op when all files match, and missing routes/ directory.
• .changeset/add-prune-option.md — Changeset entry documenting this as a minor release.

Example

# After renaming {Name} to {nickname} in the spec:
npx counterfact openapi.yaml ./out --generate --prune
# Deletes routes/pet/{id}/update/{Name}.ts before generating routes/pet/{id}/update/{nickname}.ts

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add Prune option for clearing out defunct paths and endpoints</issue_title>
<issue_description>Sometimes an OpenApi spec might change path names or endpoint names. In that case, if a consumer tries to run Counterfact again, since it will leave the old paths and routes alone it is possible to end up with multiple wild card routes at the same end path. Example:

Old path:
/pet/{id}/update/{Name}.ts
New path:
/pet/{id}/update/{nickname}.ts

In this case, the old file will be left in place and the new one created. Then when module-tree.ts attempts to resolve the path it will have ambiguity because both wildcards can be a math if they both have the same HTTP verb.

We should offer a --prune option that will clean out any paths that aren't represented in the OpenApi spec.</issue_description>

Comments on the Issue (you are @copilot in this section)

@pmcelhaney Or maybe it should detect this situation and rename {Name}.ts to {nickname}.ts

• Fixes Add Prune option for clearing out defunct paths and endpoints #1308

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[changeset-bot]

🦋 Changeset detected

Latest commit: 2fc3033

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

This PR includes changesets to release 1 package

Name	Type
counterfact	Minor

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

[pmcelhaney]

@copilot add a changes

[coveralls]

Pull Request Test Coverage Report for Build 23353533229

Details

• 135 of 141 (95.74%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 83.848%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/typescript-generator/prune.js	125	127	98.43%
src/typescript-generator/generate.js	3	7	42.86%

Totals
Change from base Build 23342753853:	0.3%
Covered Lines:	4609
Relevant Lines:	5604

---

💛 - Coveralls

[Copilot]

@copilot add a changes

Added a changeset file (.changeset/add-prune-option.md) documenting this as a minor change in commit 2fc3033.

[pmcelhaney]

@copilot add a changeset

[Copilot]

@copilot add a changeset

The changeset was already added in commit 2fc3033 as .changeset/add-prune-option.md (minor bump).