CommandLineSupport: Do not escape backslash on Windows

[michael-o]

Steps to reproduce

• JaCoCo version: 0.8.8
• Operating system: Windows
• Tool integration: Maven plugin

Have a look at this config snippet in Maven Surefire: https://github.com/apache/maven-surefire/blob/83c466698f1cf38d7b60852549393f4245f286d4/surefire-its/pom.xml#L136-L156

It produces the following output:

[INFO] --- maven-help-plugin:3.4.0:evaluate (default-cli) @ surefire-its ---
[INFO] No artifact parameter specified, using 'org.apache.maven.surefire:surefire-its:jar:3.2.4-SNAPSHOT' as project.
[INFO] Enter the Maven expression i.e. ${project.groupId} or 0 to exit?:
${jacoco-it.agent}
[INFO]
"-javaagent:C:\\Users\\mosipov\\.m2\\repository\\org\\jacoco\\org.jacoco.agent\\0.8.8\\org.jacoco.agent-0.8.8-runtime.jar=destfile=D:\\Entwicklung\\Projekte\\Maven Surefire\\surefire-its\\target\\jacoco.exec,includes=**/failsafe/*:**/failsafe/**/*:**/surefire/*:**/surefire/**/*,excludes=**/HelpMojo.class:**/shadefire/**/*:org/jacoco/**/*:com/vladium/emma/rt/*"

Expected behaviour

cmd.exe does not require bashslashes to be escaped. I have extracted the code from Maven Surefire:

        String argsss = new String[] {
            "cmd.exe",
            "/X",
            "/C",
            "\"D:\\Entwicklung\\Programme\\apache-maven-3.8.8\\bin\\mvn -e --batch-mode -Dmaven.repo.local=C:\\Users\\mosipov\\.m2\\repository org.apache.maven.plugins:maven-clean-plugin:clean -Dsurefire.version=3.2.4-SNAPSHOT \"-Djacoco.agent=-javaagent:C:\\Users\\mosipov\\.m2\\repository\\org\\jacoco\\org.jacoco.agent\\0.8.8\\org.jacoco.agent-0.8.8-runtime.jar=destfile=D:\\Entwicklung\\Projekte\\Maven Surefire\\surefire-its\\target\\jacoco.exec,includes=**/failsafe/*:**/failsafe/**/*:**/surefire/*:**/surefire/**/*,excludes=**/HelpMojo.class:**/shadefire/**/*:org/jacoco/**/*:com/vladium/emma/rt/*\" -nsu test -DtestNgVersion=5.7 -DtestNgClassifier=jdk15\""
        };

        ProcessBuilder b = new ProcessBuilder();
        b.directory(
                new File(
                        "D:\\Entwicklung\\Projekte\\Maven Surefire\\surefire-its\\target\\CheckTestNgBeforeMethodIT_testNgBeforeMethod"));
        b.command(argsss);
        b.inheritIO();
        Process process = b.start();

        int exitCode = process.waitFor();
        System.out.println(exitCode);

Output:

[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[INFO] 
[INFO] -------< org.apache.maven.plugins.surefire:testng-beforeMethod >--------
[INFO] Building TestNG @BeforeMethod annotation 1.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-cli) @ testng-beforeMethod ---
[INFO] Deleting D:\Entwicklung\Projekte\Maven Surefire\surefire-its\target\CheckTestNgBeforeMethodIT_testNgBeforeMethod\target
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.265 s
[INFO] Finished at: 2023-12-31T00:29:10+01:00
[INFO] ------------------------------------------------------------------------
0

The underlying implementation for calling the command is in Maven Shared Utils and will handle this w/o the double escaping.

Actual behaviour

Backslashes are uselessly escaped because CommandLineSupport does not differentiate between Bourne Shell input and cmd.exe.
This was foundw hile working on https://issues.apache.org/jira/browse/SUREFIRE-1810 and reported as https://issues.apache.org/jira/browse/SUREFIRE-2225.
Luckily both File and Path normalize two backslashes to one...

[marchof]

Hi @michael-o thanks for reporting this! Indeed we don't run our regression tests on windows. Indeed it looks like windows has different escape logic.

Do you know how Maven handles this and if there is an implementation or test suite we can use as a reference?

[michael-o]

Hi @michael-o thanks for reporting this! Indeed we don't run our regression tests on windows. Indeed it looks like windows has different escape logic.

Do you know how Maven handles this and if there is an implementation or test suite we can use as a reference?

Yes, Maven delegates this to Maven Shared Utils which includes a system specific command launcher. For now, I have modified this in Surefire: https://github.com/apache/maven-surefire/pull/705/files

Maven logic used throughout: https://github.com/apache/maven-shared-utils/tree/maven-shared-utils-3.4.2/src/main/java/org/apache/maven/shared/utils/cli. Entrypoint for you https://github.com/apache/maven-shared-utils/blob/2dc9eb5ea2b4ed2573bd96282a16e0340083c87a/src/main/java/org/apache/maven/shared/utils/cli/CommandLineUtils.java#L76-L79. It will either pick Bourne shell or cmd.exe and quote as necessary.

I consider the current escaping completely designed for Bourne shell.