feat(cli): support local library git inputs

[Ryan-Amirthan]

Description

Linear ticket: Closes

Allow fern docs md generate --local to resolve library documentation inputs from git repositories, including optional refs and repository-relative subpaths.

Changes Made

• Extract the existing shallow clone/ref materialization behavior from remote spec loading into @fern-api/github, preserving default-branch, branch/tag, and commit-SHA handling.
• Reuse that helper for local library docs, mount the repository root at /repo, and forward packagePath, source URL, and configured ref to the parser.
• Register process-exit cleanup for temporary repository checkouts.
• Add focused clone/path validation tests, a local git generation integration test, remote metadata regression coverage, and a CLI changelog entry.
• Updated README.md generator (if applicable)

Testing

• Unit tests added/updated
• Manual testing completed
• pnpm turbo run compile --filter @fern-api/github --filter @fern-api/configuration-loader --filter @fern-api/library-docs-generator --filter @fern-api/workspace-loader
• pnpm turbo run test --filter @fern-api/github --filter @fern-api/library-docs-generator --filter @fern-api/workspace-loader
• pnpm turbo run test --filter @fern-api/configuration-loader -- src/docs-yml/__test__/gitRefVersioning.matrix.test.ts
• pnpm turbo run depcheck --filter @fern-api/github --filter @fern-api/configuration-loader --filter @fern-api/library-docs-generator --filter @fern-api/workspace-loader
• pnpm lint:biome --fix && pnpm format:fix && pnpm check:fix
• pnpm test:ete ran 168 passing tests; the suite still reported two .fernignore timeouts, a missing FERN_ORG_TOKEN_DEV, and an existing validate snapshot mismatch.

Link to Devin session: https://app.devin.ai/sessions/33a7d2928e6a4665be1498ed388596ac
Requested by: @Ryan-Amirthan

---

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[devin-ai-integration]

Devin Review found 1 potential issue.

[github-actions]

Docs Generation Benchmark Results

Comparing PR branch against median of 5 nightly run(s) on main (latest: 2026-08-24T04:15:25Z).

Fixture	main	PR	Delta
docs	270.7s (n=5)	258.6s (35 versions)	-12.1s (-4.5%)

Docs generation runs fern generate --docs --preview end-to-end against the benchmark fixture with 35 API versions (each version: markdown processing + OpenAPI-to-IR + FDR upload).
Delta is computed against the nightly baseline on main.
Baseline from nightly run(s) on main (latest: 2026-08-24T04:15:25Z). Trigger benchmark-baseline to refresh.
Last updated: 2026-08-24 17:01 UTC

[github-actions]

SDK Generation Benchmark Results

Comparing PR branch against median of 5 nightly run(s) on main (latest: 2026-08-24T04:15:25Z).

Full benchmark table (click to expand)

Generator	Spec	main (generator)	main (E2E)	PR (generator)	Delta
csharp-sdk	square	75s (n=5)	113s (n=5)	70s	-5s (-6.7%)
go-sdk	square	137s (n=5)	298s (n=5)	118s	-19s (-13.9%)
java-sdk	square	239s (n=5)	285s (n=5)	225s	-14s (-5.9%)
php-sdk	square	64s (n=5)	N/A	49s	-15s (-23.4%)
python-sdk	square	152s (n=5)	252s (n=5)	117s	-35s (-23.0%)
ruby-sdk-v2	square	95s (n=5)	125s (n=5)	88s	-7s (-7.4%)
rust-sdk	square	228s (n=5)	215s (n=5)	158s	-70s (-30.7%)
swift-sdk	square	60s (n=5)	450s (n=5)	57s	-3s (-5.0%)
ts-sdk	square	138s (n=5)	150s (n=5)	119s	-19s (-13.8%)

main (generator): generator-only time via --skip-scripts (includes Docker image build, container startup, IR parsing, and code generation — this is the same Docker-based flow customers use via fern generate). main (E2E): full customer-observable time including build/test scripts (nightly baseline, informational). Delta is computed against generator-only baseline.
⚠️ = generation exited with a non-zero exit code (timing may not reflect a successful run).
Baseline from nightly runs on main (latest: 2026-08-24T04:15:25Z). Trigger benchmark-baseline to refresh.
Last updated: 2026-08-24 17:02 UTC