Clear out checker-level stacks on pop by jakebailey · Pull Request #62016 · microsoft/TypeScript

jakebailey · 2025-07-07T22:33:10Z

These global-ish stacks left their references behind on pop. If the contents are ephemeral (sometimes happens with types, mappers), they'll be held indefinitely.

Pull Request Overview

This PR ensures that stack-based contextual types, inference contexts, and active mapper caches are explicitly cleared when popping to avoid holding onto stale references and potential memory leaks.

Clear references in popContextualType and popInferenceContext
Adjust pushActiveMapper to reuse existing cache maps with ??=
Clear mapper entries and cache contents in popActiveMapper

Comments suppressed due to low confidence (2)

jakebailey · 2025-07-07T22:37:08Z

@typescript-bot test it

typescript-bot · 2025-07-07T22:37:12Z

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
`test top400`	✅ Started	✅ Results
`user test this`	✅ Started	✅ Results
`run dt`	✅ Started	✅ Results
`perf test this faster`	✅ Started	👀 Results

typescript-bot · 2025-07-07T22:58:47Z

Hey @jakebailey, the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

typescript-bot · 2025-07-07T23:01:01Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/62016/merge:

Everything looks good!

RyanCavanaugh

LGTM. I like to use undefined! in these situations but as any is just as good.

jakebailey · 2025-07-07T23:14:49Z

Oh, oops, that's the incantation I meant to use.

jakebailey · 2025-07-07T23:16:06Z

Need a re-review now, sorry; I definitely meant undefined! but forgot that spelling.

typescript-bot · 2025-07-07T23:23:22Z

@jakebailey
The results of the perf run you requested are in!

Here they are:

tsc

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-Unions - node (v18.15.0, x64)}
_Errors	₃₄	₃₄	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_62,370	_62,370	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,386	_50,386	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{195,399k (± 0.90%)}	_{194,163k (± 0.99%)}	_~	_192,908k	_196,693k	_{p=0.470 n=6}
_{Parse Time}	_{1.30s (± 0.79%)}	_{1.31s (± 0.48%)}	_~	_1.30s	_1.32s	_{p=0.293 n=6}
_{Bind Time}	_0.73s	_0.73s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{9.72s (± 0.36%)}	_{9.71s (± 0.17%)}	_~	_9.68s	_9.73s	_{p=0.746 n=6}
_{Emit Time}	_{2.73s (± 0.38%)}	_{2.76s (± 1.16%)}	_~	_2.72s	_2.81s	_{p=0.217 n=6}
_{Total Time}	_{14.49s (± 0.20%)}	_{14.50s (± 0.27%)}	_~	_14.44s	_14.55s	_{p=0.518 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₅₇	₅₇	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_948,912	_948,912	_~	_~	_~	_{p=1.000 n=6}
_Types	_410,889	_410,889	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,226,319k (± 0.00%)}	_{1,226,397k (± 0.01%)}	_{+78k (+ 0.01%)}	_1,226,304k	_1,226,482k	_{p=0.045 n=6}
_{Parse Time}	_{6.50s (± 0.53%)}	_{6.52s (± 0.84%)}	_~	_6.47s	_6.62s	_{p=0.806 n=6}
_{Bind Time}	_{1.87s (± 0.22%)}	_{1.88s (± 0.29%)}	_~	_1.87s	_1.88s	_{p=0.282 n=6}
_{Check Time}	_{31.94s (± 0.51%)}	_{32.01s (± 0.37%)}	_~	_31.83s	_32.16s	_{p=0.423 n=6}
_{Emit Time}	_{14.86s (± 0.63%)}	_{14.85s (± 0.56%)}	_~	_14.72s	_14.93s	_{p=0.630 n=6}
_{Total Time}	_{55.18s (± 0.36%)}	_{55.25s (± 0.21%)}	_~	_55.12s	_55.38s	_{p=0.520 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,510,641	_2,510,641	_~	_~	_~	_{p=1.000 n=6}
_Types	_892,802	_892,802	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,805,949k (± 0.00%)}	_{2,805,913k (± 0.00%)}	_~	_2,805,852k	_2,805,938k	_{p=0.093 n=6}
_{Parse Time}	_{10.51s (± 0.13%)}	_{10.50s (± 0.55%)}	_~	_10.42s	_10.60s	_{p=0.677 n=6}
_{Bind Time}	_{2.74s (± 0.91%)}	_{2.74s (± 0.79%)}	_~	_2.71s	_2.77s	_{p=1.000 n=6}
_{Check Time}	_{101.50s (± 0.91%)}	_{102.09s (± 1.52%)}	_~	_101.00s	_104.85s	_{p=0.810 n=6}
_{Emit Time}	_{0.36s (± 1.50%)}	_{0.37s (± 2.96%)}	_~	_0.35s	_0.38s	_{p=0.227 n=6}
_{Total Time}	_{115.11s (± 0.81%)}	_{115.70s (± 1.34%)}	_~	_114.51s	_118.45s	_{p=0.936 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,227,048	_1,227,048	_~	_~	_~	_{p=1.000 n=6}
_Types	_267,470	_267,470	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,852,890k (±13.23%)}	_{2,609,622k (±14.46%)}	_~	_2,365,239k	_3,097,490k	_{p=0.936 n=6}
_{Parse Time}	_{6.63s (± 1.87%)}	_{6.58s (± 1.24%)}	_~	_6.49s	_6.70s	_{p=0.423 n=6}
_{Bind Time}	_{2.17s (± 0.50%)}	_{2.16s (± 1.51%)}	_~	_2.11s	_2.20s	_{p=1.000 n=6}
_{Check Time}	_{42.91s (± 0.41%)}	_{42.81s (± 0.48%)}	_~	_42.51s	_43.03s	_{p=0.471 n=6}
_{Emit Time}	_{3.51s (± 2.82%)}	_{3.50s (± 4.94%)}	_~	_3.34s	_3.77s	_{p=0.575 n=6}
_{Total Time}	_{55.21s (± 0.33%)}	_{55.05s (± 0.48%)}	_~	_54.61s	_55.36s	_{p=0.378 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,227,048	_1,227,048	_~	_~	_~	_{p=1.000 n=6}
_Types	_267,470	_267,470	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,430,230k (± 0.01%)}	_{2,491,281k (± 5.96%)}	_~	_2,429,911k	_2,794,523k	_{p=0.173 n=6}
_{Parse Time}	_{5.42s (± 1.05%)}	_{5.41s (± 0.87%)}	_~	_5.34s	_5.48s	_{p=0.575 n=6}
_{Bind Time}	_{1.82s (± 1.12%)}	_{1.83s (± 0.75%)}	_~	_1.81s	_1.84s	_{p=0.566 n=6}
_{Check Time}	_{35.27s (± 0.34%)}	_{35.33s (± 0.47%)}	_~	_35.03s	_35.46s	_{p=0.378 n=6}
_{Emit Time}	_{3.03s (± 1.30%)}	_{3.08s (± 3.86%)}	_~	_2.97s	_3.31s	_{p=0.748 n=6}
_{Total Time}	_{45.56s (± 0.28%)}	_{45.64s (± 0.52%)}	_~	_45.34s	_45.93s	_{p=0.378 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,548	_262,548	_~	_~	_~	_{p=1.000 n=6}
_Types	_107,156	_107,156	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{441,714k (± 0.01%)}	_{441,760k (± 0.01%)}	_~	_441,722k	_441,853k	_{p=0.128 n=6}
_{Parse Time}	_{2.91s (± 0.55%)}	_{2.90s (± 0.36%)}	_~	_2.89s	_2.92s	_{p=0.615 n=6}
_{Bind Time}	_1.11s	_1.11s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{15.79s (± 0.29%)}	_{15.83s (± 0.30%)}	_~	_15.77s	_15.91s	_{p=0.147 n=6}
_{Emit Time}	_{1.31s (± 1.22%)}	_{1.30s (± 1.94%)}	_~	_1.25s	_1.32s	_{p=0.739 n=6}
_{Total Time}	_{21.12s (± 0.26%)}	_{21.15s (± 0.26%)}	_~	_21.09s	_21.25s	_{p=0.627 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₁	₇₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_225,367	_225,367	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,290	_94,290	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{371,173k (± 0.04%)}	_{371,107k (± 0.01%)}	_~	_371,040k	_371,170k	_{p=0.471 n=6}
_{Parse Time}	_{2.89s (± 0.99%)}	_{2.88s (± 1.15%)}	_~	_2.82s	_2.91s	_{p=0.462 n=6}
_{Bind Time}	_{1.60s (± 1.74%)}	_{1.58s (± 0.65%)}	_~	_1.57s	_1.60s	_{p=0.287 n=6}
_{Check Time}	_{16.38s (± 0.18%)}	_{16.47s (± 0.31%)}	_{+0.09s (+ 0.53%)}	_16.42s	_16.55s	_{p=0.006 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{20.88s (± 0.28%)}	_{20.93s (± 0.28%)}	_~	_20.83s	_20.99s	_{p=0.227 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₃₃	₃₃	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,514,764	_3,514,764	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,181,724	_1,181,724	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,562,892k (± 0.01%)}	_{3,562,912k (± 0.01%)}	_~	_3,562,599k	_3,563,249k	_{p=0.936 n=6}
_{Parse Time}	_{15.15s (± 0.41%)}	_{15.13s (± 0.56%)}	_~	_14.99s	_15.21s	_{p=0.688 n=6}
_{Bind Time}	_{4.92s (± 0.95%)}	_{4.92s (± 0.39%)}	_~	_4.90s	_4.95s	_{p=0.871 n=6}
_{Check Time}	_{97.65s (± 3.96%)}	_{99.77s (± 1.59%)}	_~	_97.69s	_102.36s	_{p=0.689 n=6}
_{Emit Time}	_{33.66s (± 7.95%)}	_{33.20s (± 8.95%)}	_~	_31.14s	_37.32s	_{p=0.810 n=6}
_{Total Time}	_{151.38s (± 2.53%)}	_{153.02s (± 2.27%)}	_~	_150.06s	_159.15s	_{p=0.575 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_318,635	_318,635	_~	_~	_~	_{p=1.000 n=6}
_Types	_137,786	_137,786	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{474,114k (± 0.02%)}	_{474,143k (± 0.03%)}	_~	_473,978k	_474,333k	_{p=0.810 n=6}
_{Parse Time}	_{5.32s (± 0.51%)}	_{5.30s (± 0.66%)}	_~	_5.26s	_5.35s	_{p=0.259 n=6}
_{Bind Time}	_{2.22s (± 0.83%)}	_{2.23s (± 0.88%)}	_~	_2.21s	_2.26s	_{p=0.807 n=6}
_{Check Time}	_{25.57s (± 0.33%)}	_{25.57s (± 0.46%)}	_~	_25.45s	_25.73s	_{p=1.000 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{33.11s (± 0.30%)}	_{33.10s (± 0.33%)}	_~	_32.95s	_33.24s	_{p=1.000 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₃₀	₃₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_666,092	_666,092	_~	_~	_~	_{p=1.000 n=6}
_Types	_199,363	_199,363	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{571,434k (± 0.04%)}	_{571,545k (± 0.02%)}	_~	_571,364k	_571,623k	_{p=0.378 n=6}
_{Parse Time}	_{4.27s (± 0.48%)}	_{4.26s (± 0.71%)}	_~	_4.21s	_4.28s	_{p=0.743 n=6}
_{Bind Time}	_{1.32s (± 1.48%)}	_{1.33s (± 0.78%)}	_~	_1.31s	_1.34s	_{p=0.406 n=6}
_{Check Time}	_{19.93s (± 0.71%)}	_{20.10s (± 1.31%)}	_~	_19.96s	_20.63s	_{p=0.199 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_0.00s	_~	_~	_~	_{p=0.405 n=6}
_{Total Time}	_{25.53s (± 0.55%)}	_{25.68s (± 1.08%)}	_~	_25.50s	_26.24s	_{p=0.378 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

Compiler-Unions - node (v18.15.0, x64)
angular-1 - node (v18.15.0, x64)
mui-docs - node (v18.15.0, x64)
self-build-src - node (v18.15.0, x64)
self-build-src-public-api - node (v18.15.0, x64)
self-compiler - node (v18.15.0, x64)
ts-pre-modules - node (v18.15.0, x64)
vscode - node (v18.15.0, x64)
webpack - node (v18.15.0, x64)
xstate-main - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

typescript-bot · 2025-07-08T00:18:49Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/62016/merge:

Everything looks good!

Clear out checker-level stacks on pop

6ed5ca3

Copilot AI review requested due to automatic review settings July 7, 2025 22:33

github-project-automation bot added this to PR Backlog Jul 7, 2025

github-project-automation bot moved this to Not started in PR Backlog Jul 7, 2025

typescript-bot assigned jakebailey Jul 7, 2025

typescript-bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Jul 7, 2025

Copilot AI reviewed Jul 7, 2025

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This was referenced Jul 7, 2025

Port TS PR 61505 - Cache mapper instantiations microsoft/typescript-go#1358

Merged

Clear out checker-level stacks on pop microsoft/typescript-go#1369

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RyanCavanaugh approved these changes Jul 7, 2025

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github-project-automation bot moved this from Not started to Needs merge in PR Backlog Jul 7, 2025

Use better incantation

db04cbe

jakebailey enabled auto-merge (squash) July 7, 2025 23:17

RyanCavanaugh approved these changes Jul 8, 2025

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jakebailey merged commit 9e20e03 into microsoft:main Jul 8, 2025
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github-project-automation bot moved this from Needs merge to Done in PR Backlog Jul 8, 2025

DanielRosenwasser added this to the TypeScript 5.9.1 milestone Jul 23, 2025

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Clear out checker-level stacks on pop#62016

Clear out checker-level stacks on pop#62016
jakebailey merged 2 commits intomicrosoft:mainfrom
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