[gh-11363] Fix pipe symbol parsing in .mvn/jvm.config

The concat_lines function in the Unix mvn script was using xargs -n 1
which split arguments by whitespace, causing pipe symbols (|) in JVM
arguments to be interpreted as shell command separators.

This fix replaces the problematic implementation with a line-by-line
reader that preserves quoted arguments and special characters while
maintaining all existing functionality:
- Comments are still removed
- Empty lines are still filtered out
- Variable substitution (MAVEN_PROJECTBASEDIR) still works
- Pipe symbols and other special characters are preserved

The Windows mvn.cmd script was already handling this correctly and
does not require changes.

Added integration test to verify pipe symbols in jvm.config work
correctly and don't cause shell parsing errors.

Author: gnodet

apache-maven/src/assembly/maven/bin/mvn

@@ -168,21 +168,19 @@ find_file_argument_basedir() {
 # concatenates all lines of a file and replaces variables
 concat_lines() {
   if [ -f "$1" ]; then
-    # First convert all CR to LF using tr
+    # Read file line by line, remove comments and empty lines, then perform variable substitution
+    # This preserves quoted arguments and doesn't split on whitespace within quotes
     tr '\r' '\n' < "$1" | \
     sed -e '/^$/d' -e 's/#.*$//' | \
-    # Replace LF with NUL for xargs
-    tr '\n' '\0' | \
-    # Split into words and process each argument
-    # Use -0 with NUL to avoid special behaviour on quotes
-    xargs -n 1 -0 | \
-    while read -r arg; do
-      # Replace variables first
-      arg=$(echo "$arg" | sed \
-        -e "s@\${MAVEN_PROJECTBASEDIR}@$MAVEN_PROJECTBASEDIR@g" \
-        -e "s@\$MAVEN_PROJECTBASEDIR@$MAVEN_PROJECTBASEDIR@g")
-
-      echo "$arg"
+    while IFS= read -r line; do
+      # Skip empty lines after comment removal
+      if [ -n "$line" ]; then
+        # Replace variables
+        line=$(echo "$line" | sed \
+          -e "s@\${MAVEN_PROJECTBASEDIR}@$MAVEN_PROJECTBASEDIR@g" \
+          -e "s@\$MAVEN_PROJECTBASEDIR@$MAVEN_PROJECTBASEDIR@g")
+        echo "$line"
+      fi
     done | \
     tr '\n' ' '
   fi

its/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng11363PipeSymbolsInJvmConfigTest.java

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.maven.it;
+
+import java.nio.file.Path;
+import java.util.Properties;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * This is a test set for <a href="https://issues.apache.org/jira/browse/MNG-11363">MNG-11363</a>:
+ * Verify that pipe symbols in .mvn/jvm.config are properly handled and don't cause shell command parsing errors.
+ */
+public class MavenITmng11363PipeSymbolsInJvmConfigTest extends AbstractMavenIntegrationTestCase {
+
+    /**
+     * Verify that pipe symbols in .mvn/jvm.config are properly handled
+     */
+    @Test
+    void testPipeSymbolsInJvmConfig() throws Exception {
+        Path basedir = extractResources("/mng-11363-pipe-symbols-jvm-config")
+                .getAbsoluteFile()
+                .toPath();
+
+        Verifier verifier = newVerifier(basedir.toString());
+        verifier.setForkJvm(true); // Use forked JVM to test .mvn/jvm.config processing
+        verifier.addCliArguments("validate");
+        verifier.execute();
+        verifier.verifyErrorFreeLog();
+
+        Properties props = verifier.loadProperties("target/pom.properties");
+        assertEquals("de|*.de|my.company.mirror.de", props.getProperty("project.properties.pom.prop.nonProxyHosts"));
+        assertEquals("value|with|pipes", props.getProperty("project.properties.pom.prop.with.pipes"));
+    }
+}

its/core-it-suite/src/test/resources/mng-11363-pipe-symbols-jvm-config/.mvn/jvm.config

@@ -0,0 +1,3 @@
+# Test for MNG-11363: Maven 4 fails to parse pipe symbols in .mvn/jvm.config
+-Dhttp.nonProxyHosts=de|*.de|my.company.mirror.de
+-Dprop.with.pipes="value|with|pipes"

its/core-it-suite/src/test/resources/mng-11363-pipe-symbols-jvm-config/pom.xml

@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+    Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you under the Apache License, Version 2.0 (the
+    "License"); you may not use this file except in compliance
+    with the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing,
+    software distributed under the License is distributed on an
+    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+    KIND, either express or implied.  See the License for the
+    specific language governing permissions and limitations
+    under the License.
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.apache.maven.its.mng11363</groupId>
+  <artifactId>test</artifactId>
+  <version>1.0</version>
+
+  <name>Maven Integration Test :: MNG-11363</name>
+  <description>Verify that JVM args can contain pipe symbols in .mvn/jvm.config.</description>
+
+  <properties>
+    <pom.prop.nonProxyHosts>${http.nonProxyHosts}</pom.prop.nonProxyHosts>
+    <pom.prop.with.pipes>${prop.with.pipes}</pom.prop.with.pipes>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.its.plugins</groupId>
+        <artifactId>maven-it-plugin-expression</artifactId>
+        <version>2.1-SNAPSHOT</version>
+        <executions>
+          <execution>
+            <id>test</id>
+            <goals>
+              <goal>eval</goal>
+            </goals>
+            <phase>validate</phase>
+            <configuration>
+              <outputFile>target/pom.properties</outputFile>
+              <expressions>
+                <expression>project/properties</expression>
+              </expressions>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>