fix(requirements check): use regex to get java version from javac output

[DavidStrausz]

Platforms affected

Android

Motivation and Context

Fixes getting the java version from the javac -version output on macOS devices when custom _JAVA_OPTIONS are set. A detailed description of the issue can be found im my comment here.

Fixes #1203

Description

Use a regex to get just the version string from the javac output. Fixes #1130.

Previously semver.coerce() would get a wrong version from a string like the following:

Picked up _JAVA_OPTIONS: -Xms1024M -Xmx2048M\njavac 1.8.0_271

With the change in this PR, the following regex is used to get the version string (1.8.0) from the output:

/javac\s+([\d.]+)/i

I also tried removing _JAVA_OPTIONS from the version check by adding env: {}, extendEnv: false to the options of the javac command like suggested here:

execa('javac', ['-version'], { all: true, env: {}, extendEnv: false })

This changed the output from:

Picked up _JAVA_OPTIONS: -Xms1024M -Xmx2048M\njavac 1.8.0_271

to:

javac 12.0.2

which subsequently let the requirements check fail again (no idea where 12.0.2 comes from). So I just went with the regex solution.

Testing

• Add android platform with fix on macOS, run cordova build android, check if requirements check succeeds
• Add android platform with fix on Windows, run cordova build android, check if requirements check succeeds
• Add unit test for javac -version output with _JAVA_OPTIONS, run unit tests

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[breautek]

I also tried removing _JAVA_OPTIONS from the version check by adding env: {}, extendEnv: false to the options of the javac command like suggested here:

Yah I don't think we can remove the environment variables, as that may contain details like JAVA_HOME used to point to the direction where Cordova should look for a path... otherwise it will find the first java variable in your path and call it a day which may not be what we want. ;)

[breautek]

Will merge by tomorrow night if there are no objections.

[PieterVanPoyer]

Looks good. I did not test it.

[breautek]

Thanks for the review @PieterVanPoyer and thank you for your contribution @DavidStrausz