#420: fix detection of java version when JAVA_TOOL_OPTIONS is set

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

@@ -220,6 +220,16 @@ protected static class Messages {
     private final Deque<Class<?>> javacClasses = new ConcurrentLinkedDeque<>();
 
     private static final Pattern JAVA_MAJOR_AND_MINOR_VERSION_PATTERN = Pattern.compile("\\d+(\\.\\d+)?");
+    private static final String JAVAC_PREFIX = "javac";
+
+    /**
+     * List of variable that may produce an output "Picked up %s: %s\n".
+     * <p>
+     * There may be more, but for Jenkins withMaven, this is enough.
+     *
+     * @see <a href="https://github.com/openjdk/jdk/blob/81e43114eca5199a0d816c02f50ecb6bc370135b/src/hotspot/share/runtime/arguments.cpp#L3074">arguments.cpp</a>
+     */
+    private static final String[] PICKED_ENV_VARS = {"_JAVA_OPTIONS", "JAVA_TOOL_OPTIONS"};
 
     /** Cache of javac version per executable (never invalidated) */
     private static final Map<String, String> VERSION_PER_EXECUTABLE = new ConcurrentHashMap<>();
@@ -258,6 +268,7 @@ private String getOutOfProcessJavacVersion(String executable) throws CompilerExc
              * up to 21 (https://docs.oracle.com/en/java/javase/21/docs/specs/man/javac.html#standard-options)
              */
             cli.addArguments(new String[] {"-version"}); //
+
             CommandLineUtils.StringStreamConsumer out = new CommandLineUtils.StringStreamConsumer();
             try {
                 int exitCode = CommandLineUtils.executeCommandLine(cli, out, out);
@@ -268,20 +279,39 @@ private String getOutOfProcessJavacVersion(String executable) throws CompilerExc
             } catch (CommandLineException e) {
                 throw new CompilerException("Error while executing the external compiler " + executable, e);
             }
-            version = extractMajorAndMinorVersion(out.getOutput());
+
+            /*
+             * javac will output the content of JAVA_TOOL_OPTIONS which may (sic) contains javac: we are forced to remove it.
+             */
+            String cleanedOutput = cleanPickedUp(out.getOutput(), CommandLineUtils.getSystemEnvVars());
+            version = extractMajorAndMinorVersion(cleanedOutput);
             VERSION_PER_EXECUTABLE.put(executable, version);
         }
         return version;
     }
 
     static String extractMajorAndMinorVersion(String text) {
+        int javacIndex = text.indexOf("javac");
         Matcher matcher = JAVA_MAJOR_AND_MINOR_VERSION_PATTERN.matcher(text);
-        if (!matcher.find()) {
+        int start = javacIndex == -1 ? 0 : javacIndex + JAVAC_PREFIX.length();
+        if (!matcher.find(start)) {
             throw new IllegalArgumentException("Could not extract version from \"" + text + "\"");
         }
         return matcher.group();
     }
 
+    static String cleanPickedUp(String text, Properties envvars) {
+        String ls = "\n";
+        String ntext = StringUtils.unifyLineSeparators(text, ls);
+        for (String env : PICKED_ENV_VARS) {
+            String value = StringUtils.unifyLineSeparators(envvars.getProperty(env), ls);
+            if (value != null) {
+                ntext = ntext.replace(String.format("Picked up %s: %s\n", env, value), "");
+            }
+        }
+        return ntext;
+    }
+
     @Override
     public CompilerResult performCompile(CompilerConfiguration config) throws CompilerException {
         File destinationDir = new File(config.getOutputLocation());

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

@@ -2,8 +2,12 @@
 
 import java.io.BufferedReader;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.io.StringReader;
+import java.nio.charset.StandardCharsets;
 import java.util.List;
+import java.util.Properties;
 import java.util.stream.Stream;
 
 import org.codehaus.plexus.compiler.CompilerMessage;
@@ -13,6 +17,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.opentest4j.AssertionFailedError;
 
 import static org.codehaus.plexus.compiler.javac.JavacCompiler.Messages.*;
 import static org.hamcrest.CoreMatchers.endsWith;
@@ -121,5 +126,51 @@ void testExtractMajorAndMinorVersion() {
         assertEquals("11.0", JavacCompiler.extractMajorAndMinorVersion("javac 11.0.22"));
         assertEquals("11.0", JavacCompiler.extractMajorAndMinorVersion("11.0.22"));
         assertEquals("21", JavacCompiler.extractMajorAndMinorVersion("javac 21"));
+        assertEquals("1.8", JavacCompiler.extractMajorAndMinorVersion("1.3.4\njavac 1.8.0_432"));
+    }
+
+    @Test
+    void testCleanPickedUp() {
+        assertEquals(
+                "This text contains CRLF\n",
+                JavacCompiler.cleanPickedUp("This text contains CRLF\r\n", new Properties()));
+
+        // files were generated by using:
+        // declare -x JAVA_TOOL_OPTIONS=$'-Daaa\n\n-Dxxx'
+        // declare -x _JAVA_OPTIONS="-Dccc"
+        // "${JAVA_8_HOME}/bin/javac" -version >
+        // plexus-compilers/plexus-compiler-javac/src/test/resources/org/codehaus/plexus/compiler/javac/java8_pickedUp.txt 2>&1
+        // "${JAVA_17_HOME}/bin/javac" -version >
+        // plexus-compilers/plexus-compiler-javac/src/test/resources/org/codehaus/plexus/compiler/javac/java17_pickedUp.txt 2>&1
+        // "${JAVA_21_HOME}/bin/javac" -version >
+        // plexus-compilers/plexus-compiler-javac/src/test/resources/org/codehaus/plexus/compiler/javac/java21_pickedUp.txt 2>&1
+        Properties envvars = new Properties();
+        envvars.setProperty("JAVA_TOOL_OPTIONS", "-Daaa\r\n\r\n-Dxxx");
+        envvars.setProperty("_JAVA_OPTIONS", "-Dccc");
+
+        assertEquals(
+                "javac 1.8.0_432\n", JavacCompiler.cleanPickedUp(readAllLines("java8_pickedUp.txt", "\n"), envvars));
+        assertEquals(
+                "javac 17.0.13\n", JavacCompiler.cleanPickedUp(readAllLines("java17_pickedUp.txt", "\r\n"), envvars));
+        assertEquals("javac 21.0.5\n", JavacCompiler.cleanPickedUp(readAllLines("java21_pickedUp.txt", "\r"), envvars));
+    }
+
+    private String readAllLines(String resource, String ls) {
+        try (InputStream is = this.getClass().getResourceAsStream(resource)) {
+            if (is == null) {
+                throw new AssertionFailedError("No such resource: " + resource + " in class " + this.getClass());
+            }
+            try (InputStreamReader isr = new InputStreamReader(is, StandardCharsets.UTF_8);
+                    BufferedReader br = new BufferedReader(isr)) {
+                StringBuilder sb = new StringBuilder();
+                for (String line = null; (line = br.readLine()) != null; ) {
+                    sb.append(line).append(ls);
+                }
+                return sb.toString();
+            }
+        } catch (IOException e) {
+            throw new AssertionFailedError(
+                    "Could not fetch lines of resource: " + resource + " in class " + this.getClass(), e);
+        }
     }
 }

plexus-compilers/plexus-compiler-javac/src/test/resources/org/codehaus/plexus/compiler/javac/java17_pickedUp.txt

@@ -0,0 +1,5 @@
+Picked up JAVA_TOOL_OPTIONS: -Daaa
+
+-Dxxx
+Picked up _JAVA_OPTIONS: -Dccc
+javac 17.0.13

plexus-compilers/plexus-compiler-javac/src/test/resources/org/codehaus/plexus/compiler/javac/java21_pickedUp.txt

@@ -0,0 +1,5 @@
+Picked up JAVA_TOOL_OPTIONS: -Daaa
+
+-Dxxx
+Picked up _JAVA_OPTIONS: -Dccc
+javac 21.0.5

plexus-compilers/plexus-compiler-javac/src/test/resources/org/codehaus/plexus/compiler/javac/java8_pickedUp.txt

@@ -0,0 +1,5 @@
+Picked up JAVA_TOOL_OPTIONS: -Daaa
+
+-Dxxx
+Picked up _JAVA_OPTIONS: -Dccc
+javac 1.8.0_432