fix: Respect unpack minimatch for symlinks within previously unpacked directories

[mmaietta]

Summary:
Fixes issue with unpack configuration when considering symlinks within previously unpacked directories. This directly fixes unpacking static .framework modules on Mac, as otherwise codesigning will fail due to symlink files/directories not being reflected in the app.asar.unpacked directory.

Fix:

• Tracks all symlinks in a list (similar as files) as to what are supposed to be unpacked.
• Adds unpacked flag as node.unpacked=true
• Extracts common logic for detecting if a path is unpacked
• Added promisified symlink and readlink
• Reuses Filesystem unit test approach for programmatically creating symlinks during tests so as to properly replicate symlinks on Win/Linux/MacOS. (committing Windows symlinks created with mklink do not get committed properly to git)

Details:
.framework has to have all symlinks reproduced in the unpacked directory for signing. The top is with electron/asar unpacked folder, the bottom is the actual framework contents.

Without this PR, codesigning will fail with QtCore.framework: bundle format unrecognized, invalid, or unsuitable

  • signing         file=dist/mac/SanitizedAppName.app platform=darwin type=distribution identity=<SanitizedIdentity> provisioningProfile=none
  ⨯ Command failed: codesign --sign <SanitizedIdentity> --force --timestamp --options runtime --entitlements ./build/entitlements.mac.plist /Users/<project-folder>/dist/mac/SanitizedAppName.app/Contents/Resources/app.asar.unpacked/node_modules/<sanitized-dep-name>/lib/Release/QtCore.framework
/Users/<project-folder>/dist/mac/SanitizedAppName.app/Contents/Resources/app.asar.unpacked/node_modules/<sanitized-dep-name>/lib/Release/QtCore.framework: bundle format unrecognized, invalid, or unsuitable

Fixes: electron-userland/electron-builder#8655 (comment)

[BlackHole1]

Note: This implementation is isolated to mac/linux. It seems symlinks created on Windows (mklink) do not get properly committed to git, they seem to be committed as an actual file and I couldn't figure out why

I encountered this problem before when reviewing #308. Creating symlinks on Windows and uploading them to GitHub will cause CI to fail. I also tried creating symlinks in git bash, but it still didn't work. Perhaps Windows symlinks and Unix symlinks are completely incompatible? I'm not sure.

The method I used is to create them dynamically during testing, rather than using a fixtures-like solution. See:

asar/test/filesystem-spec.js

Lines 16 to 30 in 044fb5f

	/**
	* Directory structure:
	* tmp
	* ├── private
	* │ └── var
	* │ ├── app
	* │ │ └── file.txt -> ../file.txt
	* │ └── file.txt
	* └── var -> private/var
	*/
	const tmpPath = path.join(__dirname, '..', 'tmp');
	const privateVarPath = path.join(tmpPath, 'private', 'var');
	const varPath = path.join(tmpPath, 'var');
	fs.mkdirSync(privateVarPath, { recursive: true });
	fs.symlinkSync(path.relative(tmpPath, privateVarPath), varPath);

[mmaietta]

Thanks @BlackHole1 ! I'll get working right on that.