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new 60dc6342b4 Fix mvn.cmd jvm.config read failing silently on Windows CI
60dc6342b4 is described below
commit 60dc6342b4042488583763df1ae41fcdfbac48d1
Author: Guillaume Nodet <[email protected]>
AuthorDate: Fri Jun 26 09:55:21 2026 +0000
Fix mvn.cmd jvm.config read failing silently on Windows CI
Replace 'for /f' with 'set /p' + input redirect to read the
JvmConfigParser temp file. 'for /f' silently produces no output
when the file is briefly locked by Windows Defender real-time
scanning, leaving JVM_CONFIG_MAVEN_OPTS empty and causing
MavenITmng4559 tests to fail intermittently on Windows CI runners.
'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. A single retry with a brief delay is added
as a safety net.
Direct stdout capture ('for /f ... in (`command`)') was tried
previously (343b518a) and reverted (7685323d) because cmd.exe's
child shell interprets special characters (pipes, ampersands) in
the captured output, breaking jvm.config values like
-Dhttp.nonProxyHosts=de|*.de.
Co-Authored-By: Claude Opus 4.6 <[email protected]>
---
apache-maven/src/assembly/maven/bin/mvn.cmd | 29 +++++++++++++++++++++++++----
1 file changed, 25 insertions(+), 4 deletions(-)
diff --git a/apache-maven/src/assembly/maven/bin/mvn.cmd
b/apache-maven/src/assembly/maven/bin/mvn.cmd
index f25f85858f..f6a1413077 100644
--- a/apache-maven/src/assembly/maven/bin/mvn.cmd
+++ b/apache-maven/src/assembly/maven/bin/mvn.cmd
@@ -184,7 +184,20 @@ if not exist "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto
endReadJvmConfig
rem Use Java source-launch mode (JDK 11+) to parse jvm.config
rem This avoids batch script parsing issues with special characters (pipes,
quotes, @, etc.)
-rem Use temp file approach with cmd /c to ensure proper file handle release
+rem Java writes parsed output to a temp file; we read it with 'set /p' + input
redirect.
+rem
+rem Why 'set /p <file' instead of 'for /f ... in (file)':
+rem - 'for /f' silently produces no output when the file is briefly locked
+rem (e.g. by Windows Defender real-time scanning), leaving
JVM_CONFIG_MAVEN_OPTS empty
+rem and causing hard-to-diagnose Maven startup failures.
+rem - 'set /p <file' uses a transient input-redirect open with different
sharing flags,
+rem making it far less susceptible to lock contention. If the file IS
locked, it
+rem emits a visible error to stderr rather than failing silently.
+rem
+rem Why not capture stdout directly ('for /f ... in (`command`)')?
+rem - cmd.exe's child shell interprets special characters (pipes |,
ampersands &, etc.)
+rem in the captured output, which breaks jvm.config values like
+rem -Dhttp.nonProxyHosts=de|*.de (the core use case for JvmConfigParser).
set "JVM_CONFIG_TEMP=%TEMP%\mvn-jvm-config-%RANDOM%-%RANDOM%.txt"
@@ -196,7 +209,7 @@ if defined MAVEN_DEBUG_SCRIPT (
echo [DEBUG] Parser arguments: "%MAVEN_HOME%\bin\JvmConfigParser.java"
"%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" "%MAVEN_PROJECTBASEDIR%"
"%JVM_CONFIG_TEMP%"
)
-rem Run parser with output file as third argument - Java writes directly to
file to avoid Windows file locking issues
+rem Run parser with output file as third argument - Java writes directly to
file
"%JAVACMD%" "%MAVEN_HOME%\bin\JvmConfigParser.java"
"%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" "%MAVEN_PROJECTBASEDIR%"
"%JVM_CONFIG_TEMP%"
set JVM_CONFIG_EXIT=%ERRORLEVEL%
@@ -215,13 +228,21 @@ if %JVM_CONFIG_EXIT% neq 0 (
exit /b 1
)
-rem Read the output file
+rem Read the output file using 'set /p' with input redirect (see comment above)
if exist "%JVM_CONFIG_TEMP%" (
if defined MAVEN_DEBUG_SCRIPT (
echo [DEBUG] Temp file contents:
type "%JVM_CONFIG_TEMP%"
)
- for /f "usebackq tokens=*" %%i in ("%JVM_CONFIG_TEMP%") do set
"JVM_CONFIG_MAVEN_OPTS=%%i"
+ set /p JVM_CONFIG_MAVEN_OPTS=<"%JVM_CONFIG_TEMP%" 2>nul
+ rem Retry once after a brief delay if the read failed (Windows Defender file
lock)
+ if not defined JVM_CONFIG_MAVEN_OPTS (
+ if defined MAVEN_DEBUG_SCRIPT (
+ echo [DEBUG] First read returned empty, retrying after delay...
+ )
+ ping -n 2 127.0.0.1 >nul 2>nul
+ set /p JVM_CONFIG_MAVEN_OPTS=<"%JVM_CONFIG_TEMP%" 2>nul
+ )
del "%JVM_CONFIG_TEMP%" 2>nul
)
