Add new option "libReplacement" by jakebailey · Pull Request #60829 · microsoft/TypeScript

jakebailey · 2024-12-19T23:42:26Z

Lib replacement (https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-5.html#supporting-lib-from-node_modules) allows specially-named packages in node_modules to replace TypeScript's bundled lib.d.ts files. This feature is always on, so we always perform resolution to look for it in case it exists. This can have a negative perf impact; it's extra watchers, extra CPU time, extra IO, etc.

This PR adds a new compiler option libReplacement to control the feature; by default, it's enabled. In TS 6.0, it will be disabled by default.

jakebailey · 2024-12-19T23:42:41Z

@typescript-bot test it

typescript-bot · 2024-12-19T23:42:45Z

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 · 2024-12-19T23:42:47Z

Looks like you're introducing a change to the public API surface area. If this includes breaking changes, please document them on our wiki's API Breaking Changes page.

Also, please make sure @DanielRosenwasser and @RyanCavanaugh are aware of the changes, just as a heads up.

typescript-bot · 2024-12-20T00:03:43Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/60829/merge:

Everything looks good!

typescript-bot · 2024-12-20T00:05:24Z

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

Everything looks the same!

You can check the log here.

typescript-bot · 2024-12-20T00:24:39Z

@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	_62,363	_62,363	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,395	_50,395	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{193,620k (± 0.76%)}	_{193,000k (± 0.10%)}	_~	_192,861k	_193,244k	_{p=0.230 n=6}
_{Parse Time}	_{1.32s (± 0.42%)}	_{1.30s (± 0.93%)}	_~	_1.29s	_1.32s	_{p=0.090 n=6}
_{Bind Time}	_0.72s	_0.71s	_{-0.01s (- 1.39%)}	_~	_~	_{p=0.001 n=6}
_{Check Time}	_{9.76s (± 0.34%)}	_{9.79s (± 0.20%)}	_{+0.04s (+ 0.36%)}	_9.76s	_9.81s	_{p=0.043 n=6}
_{Emit Time}	_{2.73s (± 0.73%)}	_{2.73s (± 0.28%)}	_~	_2.72s	_2.74s	_{p=0.869 n=6}
_{Total Time}	_{14.52s (± 0.36%)}	_{14.54s (± 0.17%)}	_~	_14.50s	_14.56s	_{p=0.628 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₃₇	₃₇	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_947,936	_947,936	_~	_~	_~	_{p=1.000 n=6}
_Types	_410,955	_410,955	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,225,783k (± 0.00%)}	_{1,224,782k (± 0.00%)}	_{-1,001k (- 0.08%)}	_1,224,709k	_1,224,835k	_{p=0.005 n=6}
_{Parse Time}	_{6.65s (± 0.62%)}	_{6.55s (± 0.56%)}	_{-0.10s (- 1.48%)}	_6.51s	_6.60s	_{p=0.006 n=6}
_{Bind Time}	_{1.89s (± 0.29%)}	_{1.88s (± 1.28%)}	_~	_1.86s	_1.93s	_{p=0.228 n=6}
_{Check Time}	_{31.99s (± 0.37%)}	_{31.96s (± 0.41%)}	_~	_31.80s	_32.13s	_{p=0.810 n=6}
_{Emit Time}	_{15.19s (± 0.25%)}	_{15.12s (± 0.65%)}	_~	_14.93s	_15.21s	_{p=0.126 n=6}
_{Total Time}	_{55.71s (± 0.17%)}	_{55.52s (± 0.35%)}	_{-0.19s (- 0.34%)}	_55.21s	_55.75s	_{p=0.045 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,449,172	_2,449,172	_~	_~	_~	_{p=1.000 n=6}
_Types	_896,410	_896,410	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,320,766k (± 0.00%)}	_{2,319,699k (± 0.00%)}	_{-1,067k (- 0.05%)}	_2,319,654k	_2,319,791k	_{p=0.005 n=6}
_{Parse Time}	_{9.40s (± 0.20%)}	_{9.39s (± 0.13%)}	_~	_9.37s	_9.40s	_{p=0.406 n=6}
_{Bind Time}	_{2.24s (± 0.18%)}	_{2.24s (± 0.37%)}	_~	_2.23s	_2.25s	_{p=0.285 n=6}
_{Check Time}	_{73.51s (± 0.49%)}	_{73.73s (± 0.64%)}	_~	_72.92s	_74.18s	_{p=0.298 n=6}
_{Emit Time}	_{0.27s (± 1.89%)}	_0.28s	_{+0.01s (+ 2.44%)}	_~	_~	_{p=0.025 n=6}
_{Total Time}	_{85.42s (± 0.43%)}	_{85.63s (± 0.54%)}	_~	_84.83s	_86.08s	_{p=0.298 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,226,880	_1,226,965	_{+85 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,745	_266,768	_{+23 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,357,644k (± 0.02%)}	_{2,457,134k (± 7.64%)}	_~	_2,335,833k	_2,699,767k	_{p=0.378 n=6}
_{Parse Time}	_{5.22s (± 1.19%)}	_{5.21s (± 1.33%)}	_~	_5.16s	_5.34s	_{p=0.689 n=6}
_{Bind Time}	_{1.75s (± 0.86%)}	_{1.76s (± 1.04%)}	_~	_1.73s	_1.78s	_{p=0.510 n=6}
_{Check Time}	_{35.23s (± 0.15%)}	_{35.03s (± 0.65%)}	_~	_34.76s	_35.39s	_{p=0.066 n=6}
_{Emit Time}	_{2.96s (± 1.03%)}	_{3.01s (± 0.98%)}	_{+0.05s (+ 1.63%)}	_2.96s	_3.04s	_{p=0.043 n=6}
_{Total Time}	_{45.18s (± 0.25%)}	_{45.01s (± 0.42%)}	_~	_44.81s	_45.37s	_{p=0.066 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,226,880	_1,226,965	_{+85 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,745	_266,768	_{+23 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,911,942k (±12.86%)}	_{3,131,439k (± 0.02%)}	_~	_3,130,166k	_3,132,105k	_{p=0.378 n=6}
_{Parse Time}	_{6.96s (± 1.31%)}	_{6.91s (± 0.77%)}	_~	_6.84s	_6.99s	_{p=0.336 n=6}
_{Bind Time}	_{2.17s (± 1.65%)}	_{2.18s (± 0.69%)}	_~	_2.16s	_2.19s	_{p=0.747 n=6}
_{Check Time}	_{42.81s (± 0.71%)}	_{42.86s (± 0.50%)}	_~	_42.54s	_43.08s	_{p=0.936 n=6}
_{Emit Time}	_{3.52s (± 2.51%)}	_{3.53s (± 1.36%)}	_~	_3.46s	_3.59s	_{p=1.000 n=6}
_{Total Time}	_{55.46s (± 0.54%)}	_{55.50s (± 0.43%)}	_~	_55.14s	_55.84s	_{p=1.000 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,439	_262,468	_{+29 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_106,628	_106,646	_{+18 (+ 0.02%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{440,204k (± 0.01%)}	_{439,119k (± 0.01%)}	_{-1,085k (- 0.25%)}	_439,031k	_439,167k	_{p=0.005 n=6}
_{Parse Time}	_{3.53s (± 1.33%)}	_{3.44s (± 0.65%)}	_{-0.09s (- 2.41%)}	_3.41s	_3.48s	_{p=0.005 n=6}
_{Bind Time}	_{1.31s (± 1.63%)}	_{1.29s (± 1.30%)}	_~	_1.27s	_1.32s	_{p=0.106 n=6}
_{Check Time}	_{18.94s (± 0.25%)}	_{18.94s (± 0.30%)}	_~	_18.87s	_19.02s	_{p=0.872 n=6}
_{Emit Time}	_{1.53s (± 0.76%)}	_{1.54s (± 1.27%)}	_~	_1.51s	_1.56s	_{p=0.222 n=6}
_{Total Time}	_{25.31s (± 0.30%)}	_{25.22s (± 0.14%)}	_~	_25.16s	_25.26s	_{p=0.065 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₀	₇₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_226,062	_226,062	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,488	_94,488	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{371,627k (± 0.01%)}	_{370,508k (± 0.03%)}	_{-1,119k (- 0.30%)}	_370,451k	_370,717k	_{p=0.005 n=6}
_{Parse Time}	_{2.90s (± 1.17%)}	_{2.87s (± 1.64%)}	_~	_2.78s	_2.92s	_{p=0.227 n=6}
_{Bind Time}	_{1.59s (± 0.97%)}	_{1.58s (± 1.35%)}	_~	_1.56s	_1.61s	_{p=0.465 n=6}
_{Check Time}	_{16.44s (± 0.20%)}	_{16.48s (± 0.34%)}	_~	_16.40s	_16.55s	_{p=0.261 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_{0.00s (±244.70%)}	_~	_0.00s	_0.01s	_{p=1.000 n=6}
_{Total Time}	_{20.93s (± 0.21%)}	_{20.93s (± 0.41%)}	_~	_20.79s	_21.00s	_{p=0.687 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,224,468	_3,224,468	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,109,187	_1,109,187	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,290,008k (± 0.01%)}	_{3,288,983k (± 0.01%)}	_{-1,026k (- 0.03%)}	_3,288,586k	_3,289,252k	_{p=0.005 n=6}
_{Parse Time}	_{14.14s (± 0.38%)}	_{14.19s (± 0.62%)}	_~	_14.09s	_14.34s	_{p=0.227 n=6}
_{Bind Time}	_{4.56s (± 0.42%)}	_{4.52s (± 0.23%)}	_{-0.04s (- 0.80%)}	_4.51s	_4.54s	_{p=0.007 n=6}
_{Check Time}	_{88.49s (± 3.32%)}	_{89.01s (± 1.88%)}	_~	_86.76s	_90.41s	_{p=0.748 n=6}
_{Emit Time}	_{27.80s (± 8.64%)}	_{28.00s (± 2.67%)}	_~	_27.40s	_29.00s	_{p=0.298 n=6}
_{Total Time}	_{134.98s (± 0.73%)}	_{135.73s (± 0.71%)}	_~	_134.37s	_136.56s	_{p=0.230 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_291,562	_291,562	_~	_~	_~	_{p=1.000 n=6}
_Types	_118,971	_118,971	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{445,402k (± 0.01%)}	_{444,426k (± 0.03%)}	_{-977k (- 0.22%)}	_444,239k	_444,607k	_{p=0.005 n=6}
_{Parse Time}	_{4.08s (± 0.65%)}	_{4.04s (± 1.05%)}	_~	_3.99s	_4.09s	_{p=0.106 n=6}
_{Bind Time}	_{1.79s (± 0.55%)}	_{1.78s (± 1.26%)}	_~	_1.76s	_1.82s	_{p=0.391 n=6}
_{Check Time}	_{18.81s (± 0.33%)}	_{18.84s (± 0.63%)}	_~	_18.64s	_18.96s	_{p=0.225 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{24.70s (± 0.35%)}	_{24.66s (± 0.64%)}	_~	_24.41s	_24.84s	_{p=1.000 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₅	₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_552,233	_552,233	_~	_~	_~	_{p=1.000 n=6}
_Types	_184,971	_184,971	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{492,410k (± 0.01%)}	_{491,348k (± 0.03%)}	_{-1,062k (- 0.22%)}	_491,069k	_491,470k	_{p=0.005 n=6}
_{Parse Time}	_{4.25s (± 0.24%)}	_{4.20s (± 0.28%)}	_{-0.05s (- 1.14%)}	_4.18s	_4.21s	_{p=0.005 n=6}
_{Bind Time}	_{1.46s (± 0.35%)}	_{1.47s (± 1.43%)}	_~	_1.44s	_1.49s	_{p=0.459 n=6}
_{Check Time}	_{24.11s (± 0.40%)}	_{24.16s (± 0.95%)}	_~	_24.00s	_24.61s	_{p=1.000 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{29.81s (± 0.35%)}	_{29.83s (± 0.76%)}	_~	_29.67s	_30.28s	_{p=0.471 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 · 2024-12-20T01:13:42Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/60829/merge:

Everything looks good!

jakebailey · 2025-01-08T22:17:42Z

I guess nobody in our extended test suite uses this feature, or at least, their use of it does not actually "help" anything. Which all is a good thing.

jakebailey · 2025-01-08T22:21:01Z

I am tentatively marking this as ready for review; it doesn't really seem like anyone is using lib replacement at all in our extended suite, and this is IMO a good optimization which avoids setting up a load of failed resolution watchers. But, maybe this just needs to wait for 6.0.

The only thing this PR is probably missing are unit tests / some verification of the options I set on it, which I believe are probably wrong (should be more than affectsSemanticDiagnostics? I can never get these right.).

jakebailey · 2025-01-10T19:18:43Z

@typescript-bot perf test tsserver-only

typescript-bot · 2025-01-10T19:18:47Z

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

Command	Status	Results
`perf test tsserver-only`	✅ Started	👀 Results

jakebailey · 2025-01-10T19:24:51Z

Consensus in the design meeting was to default this to "true" (do lib replacement) until 6.0 where we default it to "false" (don't do lib replacement).

Also, name can be bikeshedded.

typescript-bot · 2025-01-10T19:31:07Z

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

Here they are:

tsserver

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-UnionsTSServer - node (v18.15.0, x64)}
_{Req 1 - updateOpen}	_{2,325ms (± 0.27%)}	_{2,293ms (± 0.69%)}	_{-32ms (- 1.36%)}	_2,273ms	_2,314ms	_{p=0.005 n=6}
_{Req 2 - geterr}	_{5,313ms (± 0.23%)}	_{5,314ms (± 0.35%)}	_~	_5,288ms	_5,336ms	_{p=0.936 n=6}
_{Req 3 - references}	_{264ms (± 1.64%)}	_{267ms (± 1.12%)}	_~	_263ms	_269ms	_{p=0.209 n=6}
_{Req 4 - navto}	_{225ms (± 0.59%)}	_{217ms (± 0.39%)}	_{🟩-9ms (- 3.85%)}	_216ms	_218ms	_{p=0.004 n=6}
_{Req 5 - completionInfo count}	_1,357	_1,357	_~	_~	_~	_{p=1.000 n=6}
_{Req 5 - completionInfo}	_{77ms (± 2.81%)}	_{75ms (± 0.54%)}	_{-2ms (- 2.39%)}	_74ms	_75ms	_{p=0.009 n=6}
_{CompilerTSServer - node (v18.15.0, x64)}
_{Req 1 - updateOpen}	_{2,440ms (± 0.94%)}	_{2,400ms (± 0.57%)}	_{-40ms (- 1.64%)}	_2,386ms	_2,422ms	_{p=0.008 n=6}
_{Req 2 - geterr}	_{4,007ms (± 0.42%)}	_{3,995ms (± 0.58%)}	_~	_3,973ms	_4,029ms	_{p=0.298 n=6}
_{Req 3 - references}	_{279ms (± 1.12%)}	_{279ms (± 1.69%)}	_~	_273ms	_285ms	_{p=0.742 n=6}
_{Req 4 - navto}	_227ms	_{223ms (± 0.18%)}	_{-4ms (- 1.84%)}	_222ms	_223ms	_{p=0.002 n=6}
_{Req 5 - completionInfo count}	_1,519	_1,519	_~	_~	_~	_{p=1.000 n=6}
_{Req 5 - completionInfo}	_{83ms (± 5.11%)}	_{83ms (± 6.78%)}	_~	_75ms	_87ms	_{p=1.000 n=6}
_{xstate-main-1-tsserver - node (v18.15.0, x64)}
_{Req 1 - updateOpen}	_{5,280ms (± 0.63%)}	_{5,257ms (± 0.35%)}	_~	_5,224ms	_5,275ms	_{p=0.378 n=6}
_{Req 2 - geterr}	_{1,149ms (± 0.32%)}	_{1,153ms (± 1.07%)}	_~	_1,142ms	_1,176ms	_{p=0.872 n=6}
_{Req 3 - references}	_{77ms (± 4.19%)}	_{83ms (± 5.61%)}	_{🔻+6ms (+ 7.84%)}	_77ms	_87ms	_{p=0.018 n=6}
_{Req 4 - navto}	_{451ms (± 0.75%)}	_{449ms (± 0.53%)}	_~	_446ms	_451ms	_{p=0.568 n=6}
_{Req 5 - completionInfo count}	_3,450	_3,450	_~	_~	_~	_{p=1.000 n=6}
_{Req 5 - completionInfo}	_{828ms (± 1.36%)}	_{832ms (± 1.85%)}	_~	_806ms	_850ms	_{p=0.575 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

CompilerTSServer - node (v18.15.0, x64)
Compiler-UnionsTSServer - node (v18.15.0, x64)
xstate-main-1-tsserver - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

jakebailey · 2025-01-11T01:01:51Z

@@ -0,0 +1 @@
+[]


Compare to tests/baselines/reference/libReplacement(libreplacement=true).trace.json below, which has 1003 lines of traces for an empty file with lib=esnext.

Now 1,016 after we added more lib.d.ts files 😄

jakebailey · 2025-01-13T17:57:42Z

@typescript-bot test it

typescript-bot · 2025-01-13T17:57:47Z

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 · 2025-01-13T18:19:18Z

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

Everything looks the same!

You can check the log here.

typescript-bot · 2025-01-13T18:19:49Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/60829/merge:

Everything looks good!

typescript-bot · 2025-01-13T18:41:32Z

@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	_62,390	_62,390	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,395	_50,395	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{193,176k (± 0.08%)}	_{194,923k (± 1.02%)}	_~	_193,032k	_196,774k	_{p=0.230 n=6}
_{Parse Time}	_{1.30s (± 0.79%)}	_{1.30s (± 0.75%)}	_~	_1.29s	_1.31s	_{p=0.784 n=6}
_{Bind Time}	_0.73s	_0.73s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{9.78s (± 0.31%)}	_{9.75s (± 0.21%)}	_~	_9.71s	_9.77s	_{p=0.165 n=6}
_{Emit Time}	_{2.73s (± 0.43%)}	_{2.73s (± 1.10%)}	_~	_2.71s	_2.78s	_{p=0.741 n=6}
_{Total Time}	_{14.54s (± 0.18%)}	_{14.51s (± 0.34%)}	_~	_14.46s	_14.57s	_{p=0.518 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₃₇	₃₇	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_947,969	_947,969	_~	_~	_~	_{p=1.000 n=6}
_Types	_410,955	_410,955	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,225,658k (± 0.00%)}	_{1,225,670k (± 0.00%)}	_~	_1,225,593k	_1,225,743k	_{p=0.470 n=6}
_{Parse Time}	_{6.65s (± 0.86%)}	_{6.64s (± 0.65%)}	_~	_6.58s	_6.68s	_{p=0.746 n=6}
_{Bind Time}	_{1.90s (± 0.27%)}	_{1.89s (± 0.64%)}	_~	_1.87s	_1.90s	_{p=0.070 n=6}
_{Check Time}	_{32.07s (± 0.38%)}	_{32.01s (± 0.48%)}	_~	_31.83s	_32.29s	_{p=0.229 n=6}
_{Emit Time}	_{15.18s (± 0.39%)}	_{15.18s (± 0.33%)}	_~	_15.11s	_15.24s	_{p=0.936 n=6}
_{Total Time}	_{55.81s (± 0.24%)}	_{55.71s (± 0.37%)}	_~	_55.49s	_56.10s	_{p=0.065 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,445,991	_2,445,991	_~	_~	_~	_{p=1.000 n=6}
_Types	_896,571	_896,571	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,309,665k (± 0.00%)}	_{2,309,664k (± 0.00%)}	_~	_2,309,597k	_2,309,697k	_{p=0.689 n=6}
_{Parse Time}	_{8.92s (± 0.50%)}	_{8.92s (± 0.56%)}	_~	_8.88s	_8.99s	_{p=0.871 n=6}
_{Bind Time}	_{2.12s (± 0.91%)}	_{2.13s (± 0.49%)}	_~	_2.11s	_2.14s	_{p=0.869 n=6}
_{Check Time}	_{73.39s (± 0.66%)}	_{73.25s (± 0.58%)}	_~	_72.78s	_74.00s	_{p=0.471 n=6}
_{Emit Time}	_{0.28s (± 2.67%)}	_{0.29s (± 3.68%)}	_~	_0.27s	_0.30s	_{p=0.611 n=6}
_{Total Time}	_{84.72s (± 0.58%)}	_{84.58s (± 0.54%)}	_~	_84.09s	_85.39s	_{p=0.470 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,228,377	_1,228,460	_{+83 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,839	_266,863	_{+24 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,359,670k (± 0.01%)}	_{2,360,211k (± 0.01%)}	_{+540k (+ 0.02%)}	_2,359,700k	_2,360,638k	_{p=0.020 n=6}
_{Parse Time}	_{5.22s (± 0.48%)}	_{5.18s (± 0.52%)}	_{-0.04s (- 0.70%)}	_5.15s	_5.23s	_{p=0.037 n=6}
_{Bind Time}	_{1.79s (± 0.58%)}	_{1.78s (± 1.00%)}	_~	_1.76s	_1.81s	_{p=0.255 n=6}
_{Check Time}	_{35.22s (± 0.21%)}	_{35.26s (± 0.31%)}	_~	_35.14s	_35.43s	_{p=0.521 n=6}
_{Emit Time}	_{3.00s (± 1.09%)}	_{3.01s (± 0.94%)}	_~	_2.98s	_3.05s	_{p=0.748 n=6}
_{Total Time}	_{45.23s (± 0.13%)}	_{45.24s (± 0.26%)}	_~	_45.08s	_45.37s	_{p=0.936 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,228,377	_1,228,460	_{+83 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_266,839	_266,863	_{+24 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{3,036,025k (± 9.75%)}	_{2,914,614k (±12.86%)}	_~	_2,429,441k	_3,158,263k	_{p=0.378 n=6}
_{Parse Time}	_{6.98s (± 1.80%)}	_{6.93s (± 1.50%)}	_~	_6.79s	_7.02s	_{p=0.261 n=6}
_{Bind Time}	_{2.16s (± 2.14%)}	_{2.16s (± 1.16%)}	_~	_2.13s	_2.19s	_{p=1.000 n=6}
_{Check Time}	_{42.91s (± 0.66%)}	_{42.88s (± 0.44%)}	_~	_42.63s	_43.18s	_{p=0.689 n=6}
_{Emit Time}	_{3.49s (± 2.52%)}	_{3.51s (± 2.26%)}	_~	_3.38s	_3.63s	_{p=0.629 n=6}
_{Total Time}	_{55.55s (± 0.48%)}	_{55.48s (± 0.42%)}	_~	_55.10s	_55.82s	_{p=0.471 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,624	_262,651	_{+27 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_106,695	_106,714	_{+19 (+ 0.02%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{440,803k (± 0.01%)}	_{440,854k (± 0.02%)}	_~	_440,703k	_440,925k	_{p=0.128 n=6}
_{Parse Time}	_{3.55s (± 1.13%)}	_{3.54s (± 0.75%)}	_~	_3.51s	_3.59s	_{p=0.629 n=6}
_{Bind Time}	_{1.31s (± 1.01%)}	_{1.32s (± 1.00%)}	_~	_1.31s	_1.34s	_{p=0.366 n=6}
_{Check Time}	_{19.03s (± 0.40%)}	_{19.00s (± 0.67%)}	_~	_18.84s	_19.15s	_{p=0.748 n=6}
_{Emit Time}	_{1.54s (± 0.92%)}	_{1.53s (± 0.55%)}	_~	_1.51s	_1.53s	_{p=0.067 n=6}
_{Total Time}	_{25.44s (± 0.43%)}	_{25.39s (± 0.46%)}	_~	_25.25s	_25.53s	_{p=0.521 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₀	₇₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_226,095	_226,095	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,488	_94,488	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{371,770k (± 0.05%)}	_{371,735k (± 0.05%)}	_~	_371,595k	_372,090k	_{p=0.575 n=6}
_{Parse Time}	_{2.92s (± 1.26%)}	_{2.90s (± 0.70%)}	_~	_2.87s	_2.93s	_{p=0.466 n=6}
_{Bind Time}	_{1.60s (± 1.55%)}	_{1.60s (± 1.52%)}	_~	_1.56s	_1.62s	_{p=0.935 n=6}
_{Check Time}	_{16.50s (± 0.23%)}	_{16.52s (± 0.33%)}	_~	_16.46s	_16.61s	_{p=0.688 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{21.02s (± 0.24%)}	_{21.01s (± 0.41%)}	_~	_20.90s	_21.14s	_{p=1.000 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,238,957	_3,238,957	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,115,491	_1,115,491	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,306,788k (± 0.01%)}	_{3,306,726k (± 0.01%)}	_~	_3,306,272k	_3,307,061k	_{p=0.689 n=6}
_{Parse Time}	_{14.20s (± 0.59%)}	_{14.15s (± 0.43%)}	_~	_14.10s	_14.25s	_{p=0.226 n=6}
_{Bind Time}	_{4.60s (± 2.16%)}	_{4.59s (± 2.22%)}	_~	_4.54s	_4.80s	_{p=0.681 n=6}
_{Check Time}	_{87.96s (± 1.14%)}	_{89.04s (± 3.08%)}	_~	_87.25s	_94.15s	_{p=0.873 n=6}
_{Emit Time}	_{27.61s (± 1.01%)}	_{27.99s (± 2.78%)}	_~	_27.28s	_29.10s	_{p=0.471 n=6}
_{Total Time}	_{134.37s (± 0.71%)}	_{135.77s (± 2.39%)}	_~	_133.31s	_141.96s	_{p=0.936 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_291,595	_291,595	_~	_~	_~	_{p=1.000 n=6}
_Types	_118,971	_118,971	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{445,402k (± 0.02%)}	_{445,310k (± 0.04%)}	_~	_444,956k	_445,486k	_{p=0.575 n=6}
_{Parse Time}	_{5.06s (± 1.31%)}	_{5.08s (± 0.92%)}	_~	_5.03s	_5.15s	_{p=0.421 n=6}
_{Bind Time}	_{2.20s (± 1.32%)}	_{2.20s (± 1.30%)}	_~	_2.17s	_2.25s	_{p=1.000 n=6}
_{Check Time}	_{23.34s (± 0.37%)}	_{23.52s (± 2.00%)}	_~	_23.22s	_24.47s	_{p=0.689 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{30.60s (± 0.45%)}	_{30.81s (± 1.50%)}	_~	_30.45s	_31.72s	_{p=0.688 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₅	₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_555,050	_555,050	_~	_~	_~	_{p=1.000 n=6}
_Types	_186,115	_186,115	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{494,008k (± 0.01%)}	_{493,958k (± 0.02%)}	_~	_493,748k	_494,079k	_{p=0.471 n=6}
_{Parse Time}	_{3.40s (± 0.48%)}	_{3.40s (± 0.61%)}	_~	_3.39s	_3.44s	_{p=1.000 n=6}
_{Bind Time}	_{1.18s (± 0.87%)}	_{1.19s (± 1.24%)}	_~	_1.17s	_1.20s	_{p=0.562 n=6}
_{Check Time}	_{19.58s (± 0.41%)}	_{19.66s (± 1.22%)}	_~	_19.53s	_20.15s	_{p=0.936 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{24.17s (± 0.35%)}	_{24.26s (± 0.93%)}	_~	_24.11s	_24.71s	_{p=0.810 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 · 2025-01-13T19:32:49Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/60829/merge:

Everything looks good!

jakebailey · 2025-01-22T16:44:56Z

The only other thing I'm looking for is a bikeshed on the name; there are tests in the repo that call this "lib redirection", which is making me question this name.

jakebailey · 2025-01-22T16:45:25Z

 `,
 "/home/src/workspace/projects/project1/tsconfig.json": jsonToReadableText({
- compilerOptions: { composite: true, typeRoots: ["./typeroot1"], lib: ["es5", "dom"], traceResolution: true },
+ compilerOptions: { composite: true, typeRoots: ["./typeroot1"], lib: ["es5", "dom"], traceResolution: true, libReplacement: libRedirection },


Note libRedirection here.....

jakebailey · 2025-01-22T18:44:36Z

The PR which added this, #45771, uses the term "override"...

typescript-bot assigned jakebailey Dec 19, 2024

typescript-bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Dec 19, 2024

jakebailey requested review from andrewbranch and weswigham January 8, 2025 22:19

jakebailey marked this pull request as ready for review January 8, 2025 22:19

jakebailey force-pushed the lib-replacement branch from bd74a31 to a81cb69Compare January 8, 2025 22:53

jakebailey marked this pull request as draft January 10, 2025 19:24

jakebailey changed the title ~~Add new option "libReplacement", disable by default~~Add new option "libReplacement"Jan 11, 2025

jakebailey marked this pull request as ready for review January 11, 2025 01:00

jakebailey requested review from DanielRosenwasser and RyanCavanaugh January 11, 2025 01:00

jakebailey commented Jan 11, 2025
View reviewed changes

uhyo mentioned this pull request Jan 13, 2025
Guide users to enable libReplacement: trueuhyo/better-typescript-lib#59
Closed

andrewbranch approved these changes Jan 15, 2025
View reviewed changes

DanielRosenwasser mentioned this pull request Jan 16, 2025
Design Meeting Notes, 1/10/2025 #60984
Closed

RyanCavanaugh approved these changes Jan 16, 2025
View reviewed changes

jakebailey added 4 commits January 21, 2025 19:24

Add libReplacment option
be1b72c

Add explicit test for option
7ec84ce

Update tests
ded0933

Lock lib replacement behind option
c792dba

jakebailey force-pushed the lib-replacement branch from bd59e00 to c792dbaCompare January 22, 2025 03:45

jakebailey commented Jan 22, 2025
View reviewed changes

DanielRosenwasser mentioned this pull request Jan 22, 2025
TypeScript 5.8 Iteration Plan #61023
Closed

Merge branch 'main' into lib-replacement
08f08e3

jakebailey merged commit 220706e into microsoft:mainJan 24, 2025

trentm mentioned this pull request Feb 19, 2025
feat!: set compilation target to es2022 for all packages but api and semantic-conventions open-telemetry/opentelemetry-js#5456
Merged
5 tasks

ntnyq mentioned this pull request Mar 8, 2025
feat: disable libReplacement for better performance vuejs/tsconfig#35
Merged

jakebailey mentioned this pull request Jun 22, 2025
Port lib replacement and --libReplacement microsoft/typescript-go#1262
Merged

DanielRosenwasser mentioned this pull request Aug 6, 2025
Switch libReplacement to false by default #62214
Closed

CopilotAI mentioned this pull request Sep 3, 2025
Switch libReplacement to false by default and fix condition logic #62391
Merged

microsoft locked as resolved and limited conversation to collaborators Oct 15, 2025

jakebailey deleted the lib-replacement branch November 6, 2025 19:07

		@@ -0,0 +1 @@
		[] No newline at end of file

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