gnodet opened a new pull request, #12378:
URL: https://github.com/apache/maven/pull/12378
## Summary
- Replace `for /f` with `set /p` + `<` input redirect to read the
JvmConfigParser temp file in `mvn.cmd`
- `for /f` silently produces no output when the file is briefly locked by
Windows Defender real-time scanning, leaving `JVM_CONFIG_MAVEN_OPTS` empty —
this is the root cause of `MavenITmng4559SpacesInJvmOptsTest` and
`MavenITmng4559MultipleJvmArgsTest` failing intermittently on Windows CI
- `set /p <file` uses a transient input-redirect open with different sharing
flags, making it far less susceptible to lock contention; if the file IS
locked, it emits a visible error to stderr rather than failing silently
- Add a single retry with a brief delay as a safety net for the rare case
where `set /p` also hits a lock
### Background
The `JvmConfigParser.java` + temp file approach was introduced in #11365 to
fix special character handling (pipes `|`, `@` symbols, etc.) in
`.mvn/jvm.config`. Direct stdout capture via `for /f ... in (\`command\`)` was
tried (343b518a) and reverted (7685323d) because cmd.exe's child shell
interprets pipe characters in the output — defeating the purpose of the parser.
The current approach (Java writes file → `for /f` reads file) avoids the
expansion problem but introduced a silent-failure window: Windows Defender
scans newly created files and briefly locks them, and `for /f` silently skips
locked files.
CI data from the last two weeks shows this failure hits ~30% of Windows
integration test runs on master, always with the same symptom: `expected: <foo
bar> but was: <${prop.jvm-opts}>` (the JVM never received the jvm.config
properties).
### Supersedes #12337
This fixes the root cause in `mvn.cmd` itself rather than adding a
test-level retry workaround. PR #12337 added inline retries to the test methods
— that approach masks the problem for CI but doesn't help end users who hit the
same issue running Maven on Windows with a `.mvn/jvm.config` file.
## Test plan
- [ ] Windows CI integration tests pass (especially
`MavenITmng4559SpacesInJvmOptsTest` and `MavenITmng4559MultipleJvmArgsTest`)
- [ ] Linux/macOS CI unaffected (this code path is Windows-only)
- [ ] Pipe symbol test (`MavenITgh11363PipeSymbolsInJvmConfigTest`) still
passes — `set /p` does not interpret special characters during assignment
🤖 Generated with [Claude Code](https://claude.com/claude-code)
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