Cottontail JavaScriptCore builds

This repository produces static JSCOnly SDKs from upstream WebKit release tags for the Cottontail target matrix:

• macOS ARM64
• Linux x64
• Linux ARM64
• Windows x64 (also used through Windows-on-ARM x64 emulation)

Every SDK enables the complete Baseline, DFG, FTL, and WebAssembly JIT stack. Sampling profiler, remote inspector, and API tests are disabled. There are no reduced-tier build profiles.

ICU contract

JSC is compiled against the unversioned ICU 70 C API. The SDK also includes a static ICU 70.1 fallback implementation built with archive data packaging:

• executable fallback code: lib/cottontail-icu/*.{a,lib}
• checksum and ABI metadata: lib/cottontail-icu/ICU_FALLBACK.json
• separately published database: jsc/icu/70.1/icudt70l.dat

The database is deliberately absent from each SDK tarball, so it is neither duplicated four times in R2 nor accidentally copied into downstream app bundles.

Cottontail links the fallback code into its own executable, probes the operating system ICU first, and downloads the external database only when the installed ICU is absent or older than ABI 70. The data file is architecture-independent, and the build fan-in verifies that all four native ICU builds produced the exact same SHA-256 before publishing one canonical copy.

The standalone Linux jsc shell uses the bridge under bridge/ only for its build-time smoke test. Runtime selection for an embedded JSC belongs to Cottontail, and the required symbol contract is published under share/cottontail-jsc/.

GitHub Actions build and publishing

GitHub Actions resolves the newest upstream WebKit-* tag, checks out WebKit directly with the large test suites excluded, and builds all four native targets. Set the webkit_ref manual-workflow input to build an exact tag instead. Automatic selection orders tags by upstream commit date rather than the numeric-looking tag name; the workflow uses its built-in GITHUB_TOKEN to query GitHub's GraphQL API. No custom GitHub token is required.

The committed workflow checks for a new upstream tag every Monday and can also be run manually from main. The same fan-in and R2 publishing gate is used for scheduled, pushed, and manual workflows.

The R2 publisher runs only after every build and Intl smoke test passes. It uploads to the electrobun-artifacts bucket under jsc/ and requires these GitHub repository secrets:

• JSC_R2_ACCOUNT_ID
• JSC_R2_ACCESS_KEY_ID
• JSC_R2_SECRET_ACCESS_KEY

Configure this value as either a GitHub repository secret or variable. The secret takes precedence when both exist:

• JSC_R2_PUBLIC_BASE_URL (for example https://electrobun-artifacts.blackboard.sh)

Published objects use immutable build paths:

• jsc/builds/<jsc-repo-commit>/<platform>/jsc.tar.gz
• jsc/builds/<jsc-repo-commit>/manifest.json
• jsc/icu/70.1/icudt70l.dat

Convenience pointers are updated only after the complete matrix is uploaded:

• jsc/releases/<WebKit-tag>/manifest.json
• jsc/latest.json

Pull requests build and retain GitHub Actions artifacts but skip R2. Run node scripts/upload-release-r2.js --dry-run against a locally assembled release/ directory to validate the publication set without credentials.

Local stack build

Run node scripts/build-local-jsc.js to produce the host SDK consumed by a sibling Cottontail checkout. The command fingerprints committed and uncommitted JSC/WebKit inputs, reuses an unchanged SDK, and preserves the generated WebKit, WebKitBuild, and ICU build directories for local iteration.

The first invocation needs the same host dependencies as the corresponding GitHub Actions build. Set COTTONTAIL_ROOT when the Cottontail checkout is not at ../cottontail. Set DASH_LOCAL_REBUILD_JSC=1 or pass --force to rebuild an otherwise current SDK.