Microsoft/TypeScript

Computing buildInfoTime even when !isIncremental

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#60,500 opened on Nov 14, 2024

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 (3 comments) (1 reaction) (0 assignees)TypeScript (48,455 stars) (6,726 forks)batch import
Domain: tsc: --incrementalHelp WantedPossible Improvement

Description

@sheetalkamat @johnnyreilly I'm out of my depth, but I think there's maybe a bug introduced here.

I'm getting TypeError: Cannot read properties of undefined (reading 'includes') in fork-ts-checker-webpack-plugin when my project is NOT incremental: true.

Prior to this revision buildInfoTime was not computed if buildInfoPath was undefined but after this change, even though buildInfoPath is undefined, it is still attempting to compute ts_getModifiedTime(host, buildInfoPath)

Eventually, this calls to isArtifact(undefined) in fork-ts-checker-webpack-plugin\lib\typescript\worker\lib\system.js

[function isArtifact(path) {

return ((artifacts.dirs.some((dir) => path.includes(dir)) ||
    artifacts.files.some((file) => path === file)) &&
    artifacts.extensions.some((extension) => path.endsWith(extension)));

}](https://github.com/TypeStrong/fork-ts-checker-webpack-plugin/blob/0fab463b21c6edc4d94834568a3f440241d57887/src/typescript/worker/lib/system.ts#L284C1-L290C2)

Perhaps this needs to be handled in fork-ts-checker-webpack-plugin? But it seems to me that perhaps buildInfoTime could be skipped when buildInfoPath is unavailable.

Originally posted by @JasonKleban in dca9182

Contributor guide

Tech stack
typescriptnodejs
Domain
backenddeveloper experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Understanding of TypeScript compiler incremental modeFamiliarity with buildInfoPath
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Investigate the commit dca9182 that introduced the regression. The issue is that `buildInfoTime` is computed via `ts getModifiedTime(host, buildInfoPath)` even when `buildInfoPath` is undefined. The fix should guard this call with a check for `isIncremental` or that `buildInfoPath` is defined. Look at the function `computeBuildInfoTime` in the TypeScript compiler source (likely in src/compiler/emitter.ts or similar). Ensure the condition aligns with the previous behavior where it was skipped if `buildInfoPath` was undefined.