Quote javac argument files

plexus-compiler-its/src/main/it/issues-351/invoker.properties

@@ -0,0 +1,19 @@
+# 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.
+
+invoker.os.family = windows
+invoker.goals = clean compile

plexus-compiler-its/src/main/it/issues-351/pom.xml

@@ -0,0 +1,89 @@
+<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.codehaus.plexus.compiler.it</groupId>
+  <artifactId>issues-351</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <name>Issue 351: preserve multiline compiler arguments on Windows</name>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <plexus.compiler.version>@project.version@</plexus.compiler.version>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>@maven.compiler.version@</version>
+        <configuration>
+          <fork>true</fork>
+          <release>11</release>
+          <compilerArgs>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</arg>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED</arg>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED</arg>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED</arg>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED</arg>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
+            <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED</arg>
+            <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>
+            <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED</arg>
+            <arg>-XDcompilePolicy=simple</arg>
+            <arg>-Xplugin:ErrorProne
+              -Xep:DeadException:WARN</arg>
+          </compilerArgs>
+          <annotationProcessorPaths>
+            <path>
+              <groupId>com.google.errorprone</groupId>
+              <artifactId>error_prone_core</artifactId>
+              <version>2.24.1</version>
+            </path>
+          </annotationProcessorPaths>
+        </configuration>
+        <dependencies>
+          <dependency>
+            <groupId>org.codehaus.plexus</groupId>
+            <artifactId>plexus-compiler-api</artifactId>
+            <version>${plexus.compiler.version}</version>
+          </dependency>
+          <dependency>
+            <groupId>org.codehaus.plexus</groupId>
+            <artifactId>plexus-compiler-manager</artifactId>
+            <version>${plexus.compiler.version}</version>
+          </dependency>
+          <dependency>
+            <groupId>org.codehaus.plexus</groupId>
+            <artifactId>plexus-compiler-javac</artifactId>
+            <version>${plexus.compiler.version}</version>
+          </dependency>
+        </dependencies>
+      </plugin>
+    </plugins>
+  </build>
+</project>

plexus-compiler-its/src/main/it/issues-351/src/main/java/foo/Example.java

@@ -0,0 +1,25 @@
+/*
+ * 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 foo;
+
+public class Example {
+    public void createException() {
+        new RuntimeException();
+    }
+}

plexus-compiler-its/src/main/it/issues-351/verify.groovy

@@ -0,0 +1,23 @@
+/*
+ * 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.
+ */
+
+assert new File(basedir, 'target/classes/foo/Example.class').exists()
+
+def buildLog = new File(basedir, 'build.log').getText('UTF-8')
+assert buildLog.contains('[DeadException] Exception created but not thrown')

plexus-compilers/plexus-compiler-javac/src/main/java/org/codehaus/plexus/compiler/javac/JavacCompiler.java

@@ -1068,9 +1068,7 @@ private File createFileWithArguments(String[] args, String outputDirectory) thro
 
             writer = new PrintWriter(new FileWriter(tempFile));
             for (String arg : args) {
-                String argValue = arg.replace(File.separatorChar, '/');
-                writer.write("\"" + argValue + "\"");
-                writer.println();
+                writer.println(quoteArgument(arg));
             }
             writer.flush();
 
@@ -1083,6 +1081,41 @@ private File createFileWithArguments(String[] args, String outputDirectory) thro
         }
     }
 
+    /**
+     * Quotes an argument according to javac command-line argument file syntax.
+     */
+    static String quoteArgument(String argument) {
+        StringBuilder quoted = new StringBuilder(argument.length() + 2);
+        quoted.append('"');
+        for (int i = 0; i < argument.length(); i++) {
+            char c = argument.charAt(i);
+            switch (c) {
+                case '\\':
+                    quoted.append("\\\\");
+                    break;
+                case '"':
+                    quoted.append("\\\"");
+                    break;
+                case '\n':
+                    quoted.append("\\n");
+                    break;
+                case '\r':
+                    quoted.append("\\r");
+                    break;
+                case '\t':
+                    quoted.append("\\t");
+                    break;
+                case '\f':
+                    quoted.append("\\f");
+                    break;
+                default:
+                    quoted.append(c);
+                    break;
+            }
+        }
+        return quoted.append('"').toString();
+    }
+
     /**
      * Get the path of the javac tool executable to use.
      * Either given through explicit configuration or via {@link #getJavacExecutable()}.

plexus-compilers/plexus-compiler-javac/src/test/java/org/codehaus/plexus/compiler/javac/JavacCompilerTest.java

@@ -119,4 +119,29 @@ void testExtractMajorAndMinorVersion() {
         assertEquals("21", JavacCompiler.extractMajorAndMinorVersion("javac 21"));
         assertEquals("1.8", JavacCompiler.extractMajorAndMinorVersion("javac 1.8.0_432"));
     }
+
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("quoteArgumentArguments")
+    void quoteArgument(String description, String argument, String expected) {
+        assertEquals(expected, JavacCompiler.quoteArgument(argument));
+    }
+
+    private static Stream<Arguments> quoteArgumentArguments() {
+        return Stream.of(
+                Arguments.of("empty", "", "\"\""),
+                Arguments.of("plain", "-Xlint", "\"-Xlint\""),
+                Arguments.of("spaces", "two words", "\"two words\""),
+                Arguments.of("double quote", "say \"hello\"", "\"say \\\"hello\\\"\""),
+                Arguments.of(
+                        "Windows path",
+                        "C:\\Program Files\\Java\\bin\\javac.exe",
+                        "\"C:\\\\Program Files\\\\Java\\\\bin\\\\javac.exe\""),
+                Arguments.of("trailing backslash", "C:\\temp\\", "\"C:\\\\temp\\\\\""),
+                Arguments.of("literal backslash-n", "-Dvalue=\\n", "\"-Dvalue=\\\\n\""),
+                Arguments.of(
+                        "control whitespace",
+                        "line1\nline2\rline3\tline4\fline5",
+                        "\"line1\\nline2\\rline3\\tline4\\fline5\""),
+                Arguments.of("backslash and newline", "line1\\\nline2", "\"line1" + "\\\\" + "\\n" + "line2\""));
+    }
 }