perf: optimize selection-set serializer hot path + fix extensions.http leak by Copilot · Pull Request #4403 · graphql-hive/graphql-yoga

Copilot · 2026-03-19T00:31:44Z

Benchmark comparison showed the selection-set serialization branch running ~5-6% slower than main (360µs vs 348µs avg; 332k vs 351k iterations/2.5min). Also identified a correctness bug where the internal extensions.http field was leaking to clients through the new fast path.

Correctness

Strip extensions.http in stringifyWithDocument — the fast path bypassed omitInternalsFromResultErrors, so Yoga's internal HTTP status hints (extensions.http) were included in the serialized response. Now uses a shared RESULT_EXTENSIONS_OPTIONS with ignoredFields to strip internal fields, and skips the "extensions" key entirely when only internal fields are present (avoids emitting "extensions":{}).

Performance

commaEscapedKey — pre-compute ',' + escapedKey at plan compile time. The hot loop now uses field.commaEscapedKey for non-first fields, eliminating one string concatenation per non-first field (~240 ops saved per benchmark request).

isSimple flag on ProjectionPlanField — pre-computed as typeGuard === null && !hasSkip && !hasInclude && !isTypename. When true, the serializer skips four branch checks per field and jumps directly to value serialization. For the benchmark query where every field is simple, this eliminates 4 × 260 = 1,040 branches per request.

hasConditionalFields on CompiledProjectionPlan — recursively pre-computed at plan compile time. getVariableValues is now gated on plan.hasConditionalFields && plan.variableDefinitions.length > 0. Queries that declare variables but use no @skip/@include (e.g. pagination) skip coercion entirely.

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codesandbox · 2026-03-19T00:31:47Z

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theguild-bot · 2026-03-19T00:40:18Z

Apollo Federation Subgraph Compatibility Results

Federation 1 Support Federation 2 Support

`_service`	🟢
`@key (single)`	🟢
`@key (multi)`	🟢
`@key (composite)`	🟢
`repeatable @key`	🟢
`@requires`	🟢
`@provides`	🟢
`federated tracing`	🟢

`@link`	🟢
`@shareable`	🟢
`@tag`	🟢
`@override`	🟢
`@inaccessible`	🟢
`@composeDirective`	🟢
`@interfaceObject`	🟢

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theguild-bot · 2026-03-19T00:41:59Z

✅ Yoga Benchmark Results

     ✓ no_errors{mode:graphql}
     ✓ expected_result{mode:graphql}
     ✓ no_errors{mode:graphql-jit}
     ✓ expected_result{mode:graphql-jit}
     ✓ no_errors{mode:graphql-response-cache}
     ✓ expected_result{mode:graphql-response-cache}
     ✓ no_errors{mode:graphql-no-parse-validate-cache}
     ✓ expected_result{mode:graphql-no-parse-validate-cache}
     ✓ no_errors{mode:uws}
     ✓ expected_result{mode:uws}

     checks.......................................: 100.00% ✓ 694248      ✗ 0     
     data_received................................: 2.8 GB  19 MB/s
     data_sent....................................: 118 MB  786 kB/s
     http_req_blocked.............................: avg=1.58µs   min=932ns    med=1.39µs   max=1.17ms   p(90)=1.99µs   p(95)=2.19µs  
     http_req_connecting..........................: avg=2ns      min=0s       med=0s       max=158.54µs p(90)=0s       p(95)=0s      
     http_req_duration............................: avg=343.33µs min=207.74µs med=321.96µs max=25.64ms  p(90)=465.14µs p(95)=485.22µs
       { expected_response:true }.................: avg=343.33µs min=207.74µs med=321.96µs max=25.64ms  p(90)=465.14µs p(95)=485.22µs
     ✓ { mode:graphql-jit }.......................: avg=264.36µs min=207.74µs med=256.04µs max=24.39ms  p(90)=284.92µs p(95)=296.82µs
     ✓ { mode:graphql-no-parse-validate-cache }...: avg=490.32µs min=416.69µs med=470.59µs max=25.64ms  p(90)=507.6µs  p(95)=531.98µs
     ✓ { mode:graphql-response-cache }............: avg=329.53µs min=263.01µs med=321.57µs max=10.18ms  p(90)=353.39µs p(95)=366.69µs
     ✓ { mode:graphql }...........................: avg=350.78µs min=277.9µs  med=332.22µs max=16.19ms  p(90)=376.64µs p(95)=428.23µs
     ✓ { mode:uws }...............................: avg=337.96µs min=270.54µs med=324.06µs max=20.75ms  p(90)=354.17µs p(95)=367.59µs
     http_req_failed..............................: 0.00%   ✓ 0           ✗ 347124
     http_req_receiving...........................: avg=33.02µs  min=17.42µs  med=32.31µs  max=2.96ms   p(90)=39.43µs  p(95)=42.56µs 
     http_req_sending.............................: avg=10.21µs  min=5.74µs   med=9.95µs   max=1.09ms   p(90)=13.95µs  p(95)=16.48µs 
     http_req_tls_handshaking.....................: avg=0s       min=0s       med=0s       max=0s       p(90)=0s       p(95)=0s      
     http_req_waiting.............................: avg=300.09µs min=172.23µs med=279.6µs  max=25.37ms  p(90)=421.62µs p(95)=440.23µs
     http_reqs....................................: 347124  2314.129565/s
     iteration_duration...........................: avg=426.92µs min=272.22µs med=404.07µs max=25.81ms  p(90)=549.75µs p(95)=572.91µs
     iterations...................................: 347124  2314.129565/s
     vus..........................................: 1       min=1         max=2   
     vus_max......................................: 2       min=2         max=2

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…ults Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

…e unused QUOTE import) Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

…gnore Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

…serialization Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

- Fast-path stringifyString: scan for special chars, skip JSON.stringify for plain strings - Add scalarHint to ProjectionPlanField for type-specific leaf serialization (String/Int/Float/Boolean/ID) - Pre-compute hasSkip/hasInclude booleans on each plan field to avoid .length > 0 checks in hot loop - Lazy __typename lookup in projectObject: only pay for property access when type guards or __typename output exists - projectEnumValue: use direct quote-wrapping for validated enum identifiers (no JSON.stringify needed) Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

…ey fragments, use indexed loops Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

…ethods Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

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…ization + fix extensions.http leak Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com> Agent-Logs-Url: https://github.com/graphql-hive/graphql-yoga/sessions/cabef9b6-6cba-4aea-a8ac-033860eac2c7

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Copilot AI assigned Copilot and ardatan Mar 19, 2026

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Comment thread ...graphql-yoga/src/plugins/result-processor/stringify-with-document/stringify-with-document.ts Fixed

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Copilot AI and others added 9 commits March 21, 2026 18:16

feat: use selection-set-based serialization for GraphQL execution res…

317c803

…ults Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

fix: address ESLint issues (no-negated-condition, prefer-const, remov…

d466545

…e unused QUOTE import) Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

chore: remove accidentally committed jest cache, add .cache/ to .giti…

cdebe64

…gnore Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

perf: pre-compile response projection plan (Router-style) for faster …

656a29a

…serialization Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

perf: replace variables ?? {} with shared EMPTY_VARS constant

a81afbb

Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

perf: fix array bug in projectLeafValue, pre-compute response/error k…

773640a

…ey fragments, use indexed loops Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

fix: replace schema.getRootType() with v15-compatible per-operation m…

8f498c9

…ethods Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com>

Potential fix for pull request finding 'Unneeded defensive code'

596129d

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

ardatan force-pushed the copilot/optimize-execution-result-serialization branch from 415bfcb to 596129d Compare March 21, 2026 22:16

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perf: isSimple/commaEscapedKey/hasConditionalFields for faster serial…

d38b20e

…ization + fix extensions.http leak Co-authored-by: ardatan <20847995+ardatan@users.noreply.github.com> Agent-Logs-Url: https://github.com/graphql-hive/graphql-yoga/sessions/cabef9b6-6cba-4aea-a8ac-033860eac2c7

Copilot AI changed the title ~~feat: use selection-set-based serialization for GraphQL execution results~~ perf: optimize selection-set serializer hot path + fix extensions.http leak Mar 21, 2026

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