Better error handling: show GitVersion output when JSON parsing fails by Copilot · Pull Request #2029 · GitTools/actions

Copilot · 2026-04-07T12:50:25Z

When GitVersion exits with code 0 but produces non-JSON output (e.g., due to a configuration error), the task reported a generic GitVersion output is not valid JSON error with no actionable detail — the actual GitVersion output was silently discarded.

Changes

runner.ts (gitversion) — processGitVersionOutput: when gitVersionOutput === null, the full stdout is logged at info level first (keeping it visible in the build log), then the last 20 lines are embedded in the error message with a truncation note when the output is longer:
```
GitVersion output is not valid JSON (showing last 20 of N lines)
INFO [...] Working directory: ...
ERROR [...] Some actual GitVersion error here
```
Falls back to 'GitVersion output is not valid JSON, see output details' when stdout is empty.
runner.ts (gitversion) — handleOutputError: removed the direct setFailed call; instead sets stderr on the returned ExecResult and delegates failure reporting to safeExecute. Previously, safeExecute would overwrite the meaningful error with setFailed(undefined) after handleOutputError had already set the right message.
runner.ts (common) — safeExecute: fixed the non-zero exit branch to check result.stderr first, then fall back to result.error.message, rather than unconditionally casting result.stderr as string (which produced ##[error]undefined in the logs).
runner.spec.ts (gitversion) — added tests for processGitVersionOutput covering: short output (full snippet included in error), long output (truncated to last 20 lines with line-count note), and empty output (fallback message).

Agent-Logs-Url: https://github.com/GitTools/actions/sessions/53db4e50-e513-45ff-a23e-da12a78c50b2

Copilot

Pull request overview

Improves diagnostics when GitVersion returns non-JSON output despite exiting successfully, ensuring the underlying stdout is surfaced and failures are reported consistently.

Changes:

Include GitVersion stdout in the “output is not valid JSON” error path (with an empty-stdout fallback message).
Adjust GitVersion’s JSON-parse failure handling to return an ExecResult with stderr (instead of calling setFailed directly) so safeExecute reports the right message.
Fix safeExecute failure reporting to prefer result.stderr, then fall back to result.error.message to avoid ##[error]undefined.

Reviewed changes

Copilot reviewed 2 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/tools/gitversion/runner.ts	Surface non-JSON stdout in the error and return `stderr` via `ExecResult` for consistent failure reporting.
src/tools/common/runner.ts	Improve failure logging/`setFailed` behavior by handling missing `stderr` safely.
package-lock.json	Lockfile update (removes nested TypeScript entry).
dist/tools/libs/tools.mjs	Built output reflecting `safeExecute` behavior changes.
dist/tools/libs/tools.mjs.map	Source map update for the common runner changes.
dist/tools/libs/gitversion.mjs	Built output reflecting GitVersion runner error-message changes.
dist/tools/libs/gitversion.mjs.map	Source map update for GitVersion runner changes.

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Copilot · 2026-04-07T13:50:28Z

src/tools/gitversion/runner.ts

+            const gitVersionStdout = result.stdout?.trim()
+            const message = gitVersionStdout
+                ? `GitVersion output is not valid JSON\n${gitVersionStdout}`
+                : 'GitVersion output is not valid JSON, see output details'
+            return this.handleOutputError(message)


gitVersionStdout is appended verbatim into the failure message. Since exec allows up to a 10MB buffer (see src/agents/common/build-agent.ts:257), this can create extremely large error messages (noisy logs and potential truncation/command-size limits in CI log commands). Consider truncating the embedded stdout (e.g., last N lines / first N chars) and indicating that it was truncated, while still keeping the full stdout available via normal log output when possible.

@copilot apply changes based on this feedback

Addressed in 27c05f4. processGitVersionOutput now logs the full stdout at info level (so it remains visible in the build log), then embeds only the last 20 lines of trimmed output in the error message. When the output is longer than 20 lines, a note like (showing last 20 of N lines) is appended to the header. Three new tests cover: short output (full snippet included), long output (truncated with line-count note), and empty output (fallback message).

Copilot · 2026-04-07T13:50:29Z

src/tools/gitversion/runner.ts

        if (gitVersionOutput === null) {
-            return this.handleOutputError('GitVersion output is not valid JSON, see output details')
+            const gitVersionStdout = result.stdout?.trim()
+            const message = gitVersionStdout
+                ? `GitVersion output is not valid JSON\n${gitVersionStdout}`
+                : 'GitVersion output is not valid JSON, see output details'
+            return this.handleOutputError(message)
        }


There are existing GitVersion runner tests (src/tests/tools/gitversion/runner.spec.ts), but none cover the updated behavior when JSON extraction returns null. Please add/adjust a test to assert that processGitVersionOutput returns a non-zero ExecResult whose stderr includes the original stdout (and uses the fallback message when stdout is empty), so the new error detail remains stable.

@copilot apply changes based on this feedback

These tests were already added in 27c05f4 as part of addressing the previous comment. The three new tests in testOnAgent cover:

Short stdout: processGitVersionOutput returns code: -1 with stderr containing the stdout snippet

Long stdout (30 lines): truncated to last 20 lines with showing last 20 of 30 lines note

Empty stdout: fallback message 'GitVersion output is not valid JSON, see output details'

…Output tests Agent-Logs-Url: https://github.com/GitTools/actions/sessions/1ca03aec-7dbc-4be6-86ad-3d33cfb4f95b

Copilot

Pull request overview

Copilot reviewed 3 out of 8 changed files in this pull request and generated 2 comments.

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Copilot · 2026-04-07T14:12:09Z

src/tools/gitversion/runner.ts

+                const { truncated, wasTruncated, totalLines } = this.truncateOutput(gitVersionStdout)
+                const truncationNote = wasTruncated ? ` (showing last 20 of ${totalLines} lines)` : ''


The truncation note hardcodes last 20 while truncateOutput accepts maxLines. To avoid the message drifting if maxLines is ever changed, consider defining a maxLines const, passing it into truncateOutput, and using it in the note instead of a literal.

Suggested change

const { truncated, wasTruncated, totalLines } = this.truncateOutput(gitVersionStdout)

const truncationNote = wasTruncated ? ` (showing last 20 of ${totalLines} lines)` : ''

const maxLines = 20

const { truncated, wasTruncated, totalLines } = this.truncateOutput(gitVersionStdout, maxLines)

const truncationNote = wasTruncated ? ` (showing last ${maxLines} of ${totalLines} lines)` : ''

Copilot · 2026-04-07T14:12:10Z

src/tools/gitversion/runner.ts

+        const lines = output.split('\n')
+        if (lines.length <= maxLines) {
+            return { truncated: output, wasTruncated: false, totalLines: lines.length }


truncateOutput splits only on \n. If the tool emits CRLF (\r\n), the truncated snippet will retain trailing \r characters, which can make the embedded error snippet look messy. Consider splitting with /\r?\n/ (and joining with \n) to normalize line endings.

Suggested change

const lines = output.split('\n')

if (lines.length <= maxLines) {

return { truncated: output, wasTruncated: false, totalLines: lines.length }

const lines = output.split(/\r?\n/)

if (lines.length <= maxLines) {

return { truncated: lines.join('\n'), wasTruncated: false, totalLines: lines.length }

arturcic · 2026-04-07T14:27:39Z

@copilot apply changes based on the comments in this thread

Agent-Logs-Url: https://github.com/GitTools/actions/sessions/5223fef6-8ac7-4358-8010-7e7f42c5f45c

Copilot · 2026-04-07T14:31:39Z

@copilot apply changes based on the comments in this thread

Applied both suggestions in c9a6d00:

Extracted maxLines = 20 as a const and use it in the truncation note instead of the hardcoded literal
truncateOutput now splits on /\r?\n/ and joins with \n to normalize CRLF line endings

sonarqubecloud · 2026-04-07T14:32:07Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

mergify · 2026-04-07T14:37:16Z

Thank you @Copilot for your contribution!

Initial plan

e5e13d6

Copilot AI assigned Copilot and arturcic Apr 7, 2026

Copilot AI linked an issue Apr 7, 2026 that may be closed by this pull request

[ISSUE]: Better error handling in Azure #1932

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Copilot started work on behalf of arturcic April 7, 2026 12:50 View session

Copilot AI added 2 commits April 7, 2026 13:08

Improve error handling: show GitVersion output when JSON parsing fails

c62e296

Agent-Logs-Url: https://github.com/GitTools/actions/sessions/53db4e50-e513-45ff-a23e-da12a78c50b2

Rename stdout variable to gitVersionStdout for clarity

c61405d

Agent-Logs-Url: https://github.com/GitTools/actions/sessions/53db4e50-e513-45ff-a23e-da12a78c50b2

Copilot AI changed the title ~~[WIP] Fix error handling in Azure GitVersion task~~ Better error handling: show GitVersion output when JSON parsing fails Apr 7, 2026

Copilot finished work on behalf of arturcic April 7, 2026 13:14

Copilot AI requested a review from arturcic April 7, 2026 13:14

arturcic marked this pull request as ready for review April 7, 2026 13:37

Copilot AI review requested due to automatic review settings April 7, 2026 13:37

Copilot started reviewing on behalf of arturcic April 7, 2026 13:40 View session

Copilot AI reviewed Apr 7, 2026

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Copilot started work on behalf of arturcic April 7, 2026 13:52 View session

Truncate stdout in JSON parse error message and add processGitVersion…

27c05f4

…Output tests Agent-Logs-Url: https://github.com/GitTools/actions/sessions/1ca03aec-7dbc-4be6-86ad-3d33cfb4f95b

Copilot finished work on behalf of arturcic April 7, 2026 14:02

Copilot started work on behalf of arturcic April 7, 2026 14:02 View session

Copilot finished work on behalf of arturcic April 7, 2026 14:04

arturcic requested a review from Copilot April 7, 2026 14:06

Copilot started reviewing on behalf of arturcic April 7, 2026 14:06 View session

Copilot AI reviewed Apr 7, 2026

View reviewed changes

Copilot started work on behalf of arturcic April 7, 2026 14:27 View session

Use maxLines const and normalize CRLF line endings in truncateOutput

c9a6d00

Agent-Logs-Url: https://github.com/GitTools/actions/sessions/5223fef6-8ac7-4358-8010-7e7f42c5f45c

Copilot finished work on behalf of arturcic April 7, 2026 14:34

arturcic approved these changes Apr 7, 2026

View reviewed changes

arturcic merged commit 7042d12 into main Apr 7, 2026
20 checks passed

arturcic deleted the copilot/fix-azure-error-handling branch April 7, 2026 14:36

		const { truncated, wasTruncated, totalLines } = this.truncateOutput(gitVersionStdout)
		const truncationNote = wasTruncated ? ` (showing last 20 of ${totalLines} lines)` : ''

-                const { truncated, wasTruncated, totalLines } = this.truncateOutput(gitVersionStdout)
-                const truncationNote = wasTruncated ? ` (showing last 20 of ${totalLines} lines)` : ''
+                const maxLines = 20
+                const { truncated, wasTruncated, totalLines } = this.truncateOutput(gitVersionStdout, maxLines)
+                const truncationNote = wasTruncated ? ` (showing last ${maxLines} of ${totalLines} lines)` : ''

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