Bun Zig Source Audit - 2026-05-26

Audit workspace: /tmp/home-bun-parity-main

Pinned upstream: /Users/chrisbreuer/Code/bun@fd0b6f1a271fca0b8124b69f230b100f4d636af6

Summary

• packages/runtime/UPSTREAM_SHA.txt matches upstream Bun HEAD.
• packages/runtime/src/ contains 1391 Zig files.
• scripts/measure-parity.sh --values reports 98 runtime source subsystems, 128 JSC files, and the unchanged 552 / 1193 integrated baseline.
• Full upstream Zig source presence is now complete in this worktree: the 72-file source presence gap has been closed, leaving zero missing upstream Zig paths in packages/runtime/src/.
• Copied Bun corpus presence is complete for .test.ts / .test.js files: upstream Bun and Home both have 1720 paths, with zero missing and zero extra copied test files.
• The copied bundler corpus has 89 bundler/**/*.test.{ts,js} files. Current green evidence covers 86 unique files, leaving the exact 3-file frontier listed in docs/BUN_PARITY_PLAN.md.

SQL / Valkey / DNS JSC Integration Audit

• Fidelity check against /Users/chrisbreuer/Code/bun/src: packages/runtime/src/sql_jsc/** and packages/runtime/src/runtime/dns_jsc/** Zig files are byte-identical to their Bun upstream counterparts; only Bun's sibling Rust/Cargo files are absent from Home.
• packages/runtime/src/runtime/valkey_jsc/** is byte-identical for copied Zig files except ValkeyContext.zig, which already carries a local provenance comment plus a no-op unit test around the upstream empty deinit.
• Current build wiring has the standalone Valkey context reachable via home_rt.runtime.valkey.Context and pulled into the home_rt test root. The remaining SQL JSC, DNS JSC, and Valkey JSC leaves immediately reach larger unported surfaces (jsc.Codegen, DNS/c-ares bridges, socket groups, crypto, and protocol/runtime back-edges), so they should be integrated as follow-up chunks after narrow compatibility aliases are identified per leaf.
• Focused gate run on 2026-05-26: /Users/chrisbreuer/Code/Home/lang/pantry/.bin/zig build test -Dfilter=home_rt -Denable_jsc=false --summary failures exits 0 with the current worktree. During this audit it briefly stopped before the SQL/Valkey/DNS JSC chunk on an unrelated concurrent runtime/cli/test/parallel/Channel.zig Zig 0.17 whitespace parse issue; that file is outside the SQL/Valkey/DNS JSC ownership slice.

Parallel Test Runner Integration Audit

• The copied runtime/cli/test/parallel/{Channel,Coordinator,Worker,aggregate,runner}.zig files are now namespace-visible through home_rt.runtime.cli.test_.parallel alongside the previously wired FileRange.zig and Frame.zig leaves.
• Home adds only narrow compatibility around the copied source: a minimal uws socket/vtable shim in home_rt.zig, Zig 0.17 syntax cleanup for Channel's scratch buffer, and the upstream-compatible enum decode replacement for std.meta.intToEnum.
• Focused evidence currently covers channel frame ingestion/remainder handling, unknown-frame recovery, oversized-payload termination, and aggregate JUnit attribute parsing. This is compile-frontier integration, not full home test --parallel behavior; worker process spawning, coordinator scheduling, and end-to-end parallel corpus execution remain the next behavioral gates.

Native Plugin Frontier Audit

• The final bundler frontier file bundler/native-plugin.test.ts currently fails before execution as unsupported module syntax, but that parser result is not the meaningful blocker. The fixture is Bun's native bundler-plugin ABI test: it builds native_plugin.cc with node-gyp, requires the resulting .node, passes a N-API external to build.onBeforeParse, and validates BUN_PLUGIN_NAME, symbol lookup, source replacement, loader handoff, error logging, version checks, invalid free-context handling, first-plugin-wins behavior, concurrency, and crash-name reporting.
• The relevant copied Zig/header substrate is present. Local byte checks against /Users/chrisbreuer/Code/bun passed for packages/runtime/src/bundler/ParseTask.zig, packages/runtime/src/jsc/NodeModuleModule.zig, and packages/runtime/upstream/packages/bun-native-bundler-plugin-api/bundler_plugin.h. packages/runtime/src/runtime/api/JSBundler.zig already declares the JSBundlerPlugin__callOnBeforeParsePlugins extern surface, and packages/runtime/src/runtime/napi/napi.zig is present for the N-API side.
• The missing integration is the native/JSC bridge that Bun implements in src/jsc/bindings/JSBundlerPlugin.cpp, src/jsc/bindings/napi.cpp, and src/jsc/bindings/napi_external.cpp, including the private dlopen handle attached to N-API modules and the crash-handler plugin-name path. These sources are copied under packages/runtime/upstream/, but they are not yet compiled or ported into Home's JSC-enabled runtime.
• Recommended sequence: wire the copied C++ bridge or port it faithfully, ensure node-gyp built addons can load through Home's .node path, enable build.onBeforeParse to register real native callbacks, then promote bundler/native-plugin.test.ts with single-file corpus evidence. A corpus-local .node mock should not be counted as parity.

Closed Source Presence Gap

Copied paths grouped by top-level upstream source directory:

Copied paths:

• ast_jsc/logger_jsc.zig
• css_jsc/color_js.zig
• css_jsc/css_internals.zig
• css_jsc/error_jsc.zig
• http_jsc/headers_jsc.zig
• http_jsc/websocket_client.zig
• http_jsc/websocket_client/CppWebSocket.zig
• http_jsc/websocket_client/WebSocketDeflate.zig
• http_jsc/websocket_client/WebSocketProxy.zig
• http_jsc/websocket_client/WebSocketProxyTunnel.zig
• http_jsc/websocket_client/WebSocketUpgradeClient.zig
• js_parser_jsc/Macro.zig
• js_parser_jsc/expr_jsc.zig
• patch_jsc/testing.zig
• runtime/cli/test/parallel/Channel.zig
• runtime/cli/test/parallel/Coordinator.zig
• runtime/cli/test/parallel/Worker.zig
• runtime/cli/test/parallel/aggregate.zig
• runtime/cli/test/parallel/runner.zig
• runtime/dns_jsc/cares_jsc.zig
• runtime/dns_jsc/dns.zig
• runtime/dns_jsc/options_jsc.zig
• runtime/valkey_jsc/ValkeyCommand.zig
• runtime/valkey_jsc/index.zig
• runtime/valkey_jsc/js_valkey.zig
• runtime/valkey_jsc/js_valkey_functions.zig
• runtime/valkey_jsc/protocol_jsc.zig
• runtime/valkey_jsc/valkey.zig
• semver_jsc/SemverObject.zig
• semver_jsc/SemverString_jsc.zig
• sql_jsc/mysql.zig
• sql_jsc/mysql/JSMySQLConnection.zig
• sql_jsc/mysql/JSMySQLQuery.zig
• sql_jsc/mysql/MySQLConnection.zig
• sql_jsc/mysql/MySQLContext.zig
• sql_jsc/mysql/MySQLQuery.zig
• sql_jsc/mysql/MySQLRequestQueue.zig
• sql_jsc/mysql/MySQLStatement.zig
• sql_jsc/mysql/MySQLValue.zig
• sql_jsc/mysql/protocol/DecodeBinaryValue.zig
• sql_jsc/mysql/protocol/ResultSet.zig
• sql_jsc/mysql/protocol/Signature.zig
• sql_jsc/mysql/protocol/any_mysql_error_jsc.zig
• sql_jsc/mysql/protocol/error_packet_jsc.zig
• sql_jsc/postgres.zig
• sql_jsc/postgres/AuthenticationState.zig
• sql_jsc/postgres/DataCell.zig
• sql_jsc/postgres/PostgresRequest.zig
• sql_jsc/postgres/PostgresSQLConnection.zig
• sql_jsc/postgres/PostgresSQLContext.zig
• sql_jsc/postgres/PostgresSQLQuery.zig
• sql_jsc/postgres/PostgresSQLStatement.zig
• sql_jsc/postgres/SASL.zig
• sql_jsc/postgres/Signature.zig
• sql_jsc/postgres/command_tag_jsc.zig
• sql_jsc/postgres/error_jsc.zig
• sql_jsc/postgres/protocol/error_response_jsc.zig
• sql_jsc/postgres/protocol/notice_response_jsc.zig
• sql_jsc/postgres/types/PostgresString.zig
• sql_jsc/postgres/types/bool.zig
• sql_jsc/postgres/types/bytea.zig
• sql_jsc/postgres/types/date.zig
• sql_jsc/postgres/types/json.zig
• sql_jsc/postgres/types/tag_jsc.zig
• sql_jsc/shared/CachedStructure.zig
• sql_jsc/shared/ObjectIterator.zig
• sql_jsc/shared/QueryBindingIterator.zig
• sql_jsc/shared/SQLDataCell.zig
• sys_jsc/error_jsc.zig
• sys_jsc/fd_jsc.zig
• sys_jsc/signal_code_jsc.zig
• url_jsc/url_jsc.zig

Recount Commands

git -C /Users/chrisbreuer/Code/bun rev-parse HEAD
cat packages/runtime/UPSTREAM_SHA.txt
./scripts/measure-parity.sh --values
find /Users/chrisbreuer/Code/bun/test -type f \( -name '*.test.ts' -o -name '*.test.js' \) | wc -l
find packages/runtime/test/bun-corpus -type f \( -name '*.test.ts' -o -name '*.test.js' \) | wc -l