feat(cli): allow absolute API spec paths in generators.yml

[FedeZara]

Summary

• Allow absolute paths in generators.yml for OpenAPI, GraphQL, OpenRPC, and protobuf specs, plus overrides and overlays.
• Add shared path helpers in @fern-api/fs-utils and propagate resolved paths through workspace loading, OSS validation, generation prep, and fern api update.

Context

This is the feature follow-up to #15953, which intentionally rejects absolute OpenAPI paths with a user-facing config error to fix Sentry CLI-18 / CLI-46 without changing supported configuration semantics yet.

Linear: https://linear.app/buildwithfern/issue/FER-10741/allow-absolute-api-spec-paths-in-generatorsyml

Test plan

• pnpm turbo run test --filter @fern-api/fs-utils --filter @fern-api/workspace-loader --filter @fern-api/lazy-fern-workspace --filter @fern-api/oss-validator --filter @fern-api/cli
• Manual: generators.yml with absolute OpenAPI path loads and fern generate --local succeeds when the file exists locally

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[github-actions]

Docs Generation Benchmark Results

Comparing PR branch against median of 5 nightly run(s) on main (latest: 2026-05-22T05:19:54Z).

Fixture	main	PR	Delta
docs	211.4s (n=5)	207.9s (35 versions)	-3.5s (-1.7%)

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: 2026-05-22T05:19:54Z). Trigger benchmark-baseline to refresh.
Last updated: 2026-05-22 13:20 UTC

[github-actions]

SDK Generation Benchmark Results

Comparing PR branch against median of 5 nightly run(s) on main (latest: 2026-05-22T05:19:54Z).

Full benchmark table (click to expand)

Generator	Spec	main (generator)	main (E2E)	PR (generator)	Delta
csharp-sdk	square	73s (n=5)	109s (n=5)	62s	-11s (-15.1%)
go-sdk	square	136s (n=5)	294s (n=5)	131s	-5s (-3.7%)
java-sdk	square	209s (n=5)	286s (n=5)	181s	-28s (-13.4%)
php-sdk	square	62s (n=5)	80s (n=5)	52s	-10s (-16.1%)
python-sdk	square	128s (n=5)	229s (n=5)	129s	+1s (+0.8%)
ruby-sdk-v2	square	92s (n=5)	118s (n=5)	82s	-10s (-10.9%)
rust-sdk	square	170s (n=5)	164s (n=5)	157s	-13s (-7.6%)
swift-sdk	square	63s (n=5)	746s (n=5)	47s	-16s (-25.4%)
ts-sdk	square	234s (n=5)	240s (n=5)	224s	-10s (-4.3%)

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: 2026-05-22T05:19:54Z). Trigger benchmark-baseline to refresh.
Last updated: 2026-05-22 13:23 UTC