Migrate bridge e2e tests from forEachEngine to regressionTest harness

[Copilot]

Migrates bridge package end-to-end tests from the legacy forEachEngine dual-run pattern to the stricter regressionTest harness, which adds serializer round-trip validation, traversal coverage checks, and GraphQL replay.

Serializer fixes

Fixed the serializeToolBlock function to properly round-trip tool self-wire patterns that previously broke parse → serialize → parse:

Fix	Details
Expression self-wires	const.x + 1, const.x * 5, const.x >= 18 now reconstruct from internal __expr_* fork handles
Ternary self-wires	const.flag ? "POST" : "GET" using cond/thenValue/elseValue wire properties
Coalesce/fallback self-wires	context.x ?? "5000" using fallbacks array with type: "nullish"
String interpolation self-wires	"city={const.city}" reconstructed from __concat_* fork handles
Element-scoped tool handles	Loop-scoped with blocks now serialize correctly inside array mapping braces

Test tool infrastructure

Added universal test tools in test/utils/bridge-tools.ts:

• test.sync.multitool — Sync echo tool with .bridge = { sync: true } metadata
• test.batch.multitool — Batch echo tool with .bridge = { batch: { maxBatchSize: 100, flush: "microtask" } } metadata; returns Error for items with _error set

Migrated files (12/28)

• fallback-bug.test.ts — Restructured with test.multitool as controllable primary source to make all || fallback paths exercisable
• chained.test.ts — 3-tool chain verified via test.multitool echo behavior
• string-interpolation.test.ts — Combined 8 template tests into 3 bridge operations; formatter round-trip tests kept as standalone describe blocks
• interpolation-universal.test.ts — Split into fallback and ternary regression groups
• prototype-pollution.test.ts — Converted to direct engine loop (cannot use regressionTest — see bugs below)
• ternary.test.ts — Parser/serializer tests unchanged; execution tests split across 4 regressionTest blocks + 2 direct-execution blocks for patterns with serializer issues; refFallback trace divergence resolved with function assertor
• expressions.test.ts — 3 regressionTest blocks covering arithmetic, operator precedence, and safe flag propagation; short-circuit side-effect tests moved to test/legacy/
• force-wire.test.ts — Force tool execution with test.multitool; timing and force catch null tests moved to test/legacy/
• infinite-loop-protection.test.ts — Array mapping and non-circular chain via regressionTest; circular dependency as standalone forEachEngine; runtime-only ExecutionTree depth ceiling kept as standalone describe
• tool-self-wires-runtime.test.ts — 9 scenarios covering constant wires, expressions, ternary, coalesce, string interpolation, and httpCall-style multi-tool bridges (unblocked by serializer fix)
• native-batching.test.ts — 3 scenarios using test.batch.multitool for batch echo, trace/log validation, and partial failure with catch fallbacks (unblocked by batch tool + element-scoped tool serializer fix)

Legacy tests (test/legacy/)

19 files remain in test/legacy/ with a comprehensive README.md documenting per-file blockers and suggested migration approaches. These files still run via forEachEngine and are included in the test script. Common blockers:

• Side-effect inspection — Spy tools, call-count tracking, timing assertions incompatible with data-driven harness
• Custom tool metadata — Pipe syntax tests need transforming tools beyond echo
• Direct API usage — ExecutionTree, BridgeRuntimeError property inspection, parseBridge calls
• Compiler skips — Many tests use skip: engine === "compiled" for unsupported features

Serializer bugs discovered (not yet fixed)

Bug	Impact
Traverses __proto__/constructor on wire path objects	Produces a.__proto__ <- i.x[] as [object Object] {}
Drops alias references in `
Converts template strings in `
Renames iterator variables (it → item)	Breaks ternary refs inside array mappings

Known remaining issues

• Ternary.refFallback: runtime lazily skips fallback tool (0 traces) while compiler eagerly calls it (1 trace) — resolved with function-based assertTraces accepting both values
• 19 files remain in test/legacy/ pending further serializer fixes and harness enhancements

---

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	bridge	ce9f966	Commit Preview URL Branch Preview URL	Mar 13 2026, 10:18 AM

[aarne]

@copilot

continue migrating the testcases.

any testcase that you are not able to migrate move it to test/legacy folder and create a README.md in that folder with all action items to do before we can migrate the tests

for compiler incompatibility issues just create a assertion to downgrade to runner

[Copilot]

@copilot

continue migrating the testcases.
...

Continued migration in commits d198728–a6cfc0b:

Migrated to regressionTest: expressions.test.ts, force-wire.test.ts, infinite-loop-protection.test.ts (plus ternary.test.ts fix)

Moved to test/legacy/: 19 files that can't be migrated yet due to serializer round-trip bugs, side-effect spying, custom tool metadata, timing assertions, or direct API usage. Created test/legacy/README.md with per-file blockers and action items.

All 1140 tests passing, 0 failures. The legacy files still run via the updated test script.

[aarne]

@copilot start taking legacy tests one by one and fixing them

Start with parser roundtrip

Then move to timing tests and validate via assertTraces function or from assertLogs

Create a new universal test tool for batching and use it in tests

[Copilot]

@copilot start taking legacy tests one by one and fixing them

Start with parser roundtrip...

Progress in commits 19f6164–5736138:

Parser roundtrip fixes (15073cc): Fixed the serializer to properly round-trip tool self-wire expressions (const.x + 1), ternary (const.flag ? "POST" : "GET"), coalesce (context.x ?? "5000"), string interpolation ("city={const.city}"), and element-scoped tool handles in loop blocks. This unblocked several test migrations.

New test tools: Added test.sync.multitool (sync flag) and test.batch.multitool (batch flag) to bridge-tools.ts.

Migrated: tool-self-wires-runtime.test.ts (9 scenarios), native-batching.test.ts (3 scenarios + empty array coverage), fixed infinite-loop-protection.test.ts.

19 files remain in test/legacy/ — updated README.md with per-file blockers, suggested migration approach, and common patterns (allowDowngrade for compiler skips, assertTraces for call-count/timing, assertError for BridgeRuntimeError inspection).

[github-actions]

Bencher Report

Branch	copilot/migrate-bridge-package-tests
Testbed	ubuntu-latest

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Benchmark	Latency	nanoseconds (ns)
compiled: absolute baseline (passthrough, no tools)	📈 view plot ⚠️ NO THRESHOLD	0.00 ns
compiled: array + SYNC tool-per-element 10	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
compiled: array + SYNC tool-per-element 100	📈 view plot ⚠️ NO THRESHOLD	0.02 ns
compiled: array + tool-per-element 10	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
compiled: array + tool-per-element 100	📈 view plot ⚠️ NO THRESHOLD	0.04 ns
compiled: chained 3-tool fan-out	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
compiled: flat array 10 items	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
compiled: flat array 100 items	📈 view plot ⚠️ NO THRESHOLD	0.02 ns
compiled: flat array 1000 items	📈 view plot ⚠️ NO THRESHOLD	0.12 ns
compiled: nested array 10x10	📈 view plot ⚠️ NO THRESHOLD	0.03 ns
compiled: nested array 20x10	📈 view plot ⚠️ NO THRESHOLD	0.05 ns
compiled: nested array 5x5	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
compiled: short-circuit (overdefinition bypass)	📈 view plot ⚠️ NO THRESHOLD	0.00 ns
compiled: simple chain (1 tool)	📈 view plot ⚠️ NO THRESHOLD	0.00 ns
exec: absolute baseline (passthrough, no tools)	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
exec: array + SYNC tool-per-element 10	📈 view plot ⚠️ NO THRESHOLD	0.11 ns
exec: array + SYNC tool-per-element 100	📈 view plot ⚠️ NO THRESHOLD	0.96 ns
exec: array + tool-per-element 10	📈 view plot ⚠️ NO THRESHOLD	0.13 ns
exec: array + tool-per-element 100	📈 view plot ⚠️ NO THRESHOLD	1.08 ns
exec: chained 3-tool fan-out	📈 view plot ⚠️ NO THRESHOLD	0.06 ns
exec: flat array 10 items	📈 view plot ⚠️ NO THRESHOLD	0.02 ns
exec: flat array 100 items	📈 view plot ⚠️ NO THRESHOLD	0.10 ns
exec: flat array 1000 items	📈 view plot ⚠️ NO THRESHOLD	0.87 ns
exec: nested array 10x10	📈 view plot ⚠️ NO THRESHOLD	0.16 ns
exec: nested array 20x10	📈 view plot ⚠️ NO THRESHOLD	0.30 ns
exec: nested array 5x5	📈 view plot ⚠️ NO THRESHOLD	0.06 ns
exec: short-circuit (overdefinition bypass)	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
exec: simple chain (1 tool)	📈 view plot ⚠️ NO THRESHOLD	0.01 ns
parse: large bridge (20 handles x 5 wires)	📈 view plot ⚠️ NO THRESHOLD	1.35 ns
parse: simple bridge	📈 view plot ⚠️ NO THRESHOLD	0.04 ns

🐰 View full continuous benchmarking report in Bencher