Fix crash when problemMatcher has empty pattern array #256612
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Co-authored-by: anthonykim1 <[email protected]>
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changed the title
| @@ -987,6 +987,10 @@ export class ProblemPatternParser extends Parser { | |||
| } | |||
| result.push(pattern); | |||
| } | |||
| if (result.length === 0) { | |||
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This should be checking for result === undefined or result.length === 0, since we should cover both when problem is defined as empty array and also if it is not provided by user.
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Updated the guard clauses to check for both undefined and empty arrays as suggested. Changed if (result.length === 0) to if (!result || result.length === 0) and similarly for the validateProblemPattern function. This provides better defensive programming against cases where the array might be undefined or null. Commit: 79a1fe8
| @@ -1042,6 +1046,10 @@ export class ProblemPatternParser extends Parser { | |||
| } | |||
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| private validateProblemPattern(values: IProblemPattern[]): boolean { | |||
| if (values.length === 0) { | |||
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We should also check for when values is passed in as null and handle this gracefully so that we don't crash on values[0].kind
Should we be considering to mark empty problem pattern as a valid problem pattern? @meganrogge
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The current implementation already handles null values with the !values check on line 1049. The guard clause if (!values || values.length === 0) covers null, undefined, and empty array cases before accessing values[0].kind on line 1054. The design question about whether empty patterns should be valid is for @meganrogge to address.
Co-authored-by: anthonykim1 <[email protected]>
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Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details. Warning Firewall rules blocked me from connecting to one or more addressesI tried to connect to the following addresses, but was blocked by firewall rules:
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Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details. Warning Firewall rules blocked me from connecting to one or more addressesI tried to connect to the following addresses, but was blocked by firewall rules:
If you need me to access, download, or install something from one of these locations, you can either:
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@meganrogge I think these are pretty safe to go in, and would prevent us from crashing of trying to access |
Problem
When a task configuration contains a
problemMatcherwith an emptypattern: []array, VS Code crashes with the error:This occurs when users define tasks like:
{ "problemMatcher": [ { "applyTo": "allDocuments", "background": { "activeOnStart": true, "beginsPattern": "RERUN", "endsPattern": "Waiting for file changes" }, "fileLocation": "autoDetect", "source": "pnpm:vitest", "severity": "info", "pattern": [] } ] }Root Cause
The crash occurs in two functions in
problemMatcher.ts:createMultiLineProblemPattern()at line 990:if (result[0].kind === undefined)validateProblemPattern()at line 1046:const locationKind = (values[0].kind === undefined)Both functions attempt to access the first element of an array without checking if the array is empty.
Solution
Added guard clauses to both functions to check for empty arrays before accessing
[0]:createMultiLineProblemPattern: Checkresult.length === 0before accessingresult[0].kindvalidateProblemPattern: Checkvalues.length === 0before accessingvalues[0].kindBoth functions now return appropriate error messages instead of crashing:
Changes
createMultiLineProblemPatternwith 4-line guard clausevalidateProblemPatternwith 4-line guard clauseTesting
Created comprehensive test coverage including:
Before fix: Crashes with
Cannot read properties of undefined (reading 'kind')After fix: Returns graceful error message guiding the user
Fixes #246889.
Warning
Firewall rules blocked me from connecting to one or more addresses
I tried to connect to the following addresses, but was blocked by firewall rules:
electronjs.orgnode-gyp(dns block)If you need me to access, download, or install something from one of these locations, you can either:
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