UnsupportedOperationException due to toPath() call on PipePath

[sciwhiz12]

Logfile: https://gist.github.com/Bricktricker/67bbcf61eafe403d240060dfe798874d (from orig. reporter on The Forge Project discord)

DiffPatch/src/main/java/codechicken/diffpatch/cli/PatchOperation.java

Lines 132 to 133 in 7d2555a

	if (outputPath.isFile()) {
	Path out = outputPath.toPath();

The given lines are the root of the issue here: when OutputPath#isFile() is true, OutputPath#toPath() is called to convert the path into a Path object.
However, this causes an issue when the outputPath variable holds a PipePath: PipePath returns true for #isFile() but throws an UnsupportedOperationException for #toPath() (presumably because you cannot obtain a Path object for pipes). This causes the aforementioned crash via UnsupportedOperationException.

Although there is an if-check present before those lines, which short-circuits when the outputPath is a Pipe, this only returns and stops when the PipePath does not have a ArchiveFormat. If the PipePath does contain an ArchiveFormat, then this if-check passes and it goes straight into the aforementioned currently-crashing code.

DiffPatch/src/main/java/codechicken/diffpatch/cli/PatchOperation.java

Lines 126 to 130 in 7d2555a

	if (outputPath.getType().isPipe() && outputPath.getFormat() == null) {
	log("Err: Output detected as pipe but no format is specified.");
	printHelp();
	return new Result<>(-1);
	}

The bug was reported via a user using ForgeGradle 4.0.14 and 4.0.15 (with 4.0.14 being the version of ForgeGradle that first switched to DiffPatch). The offending code which causes the issue is this, where a ByteArrayOutputStream with an archive format of ArchiveFormat.ZIP is given as the output path of the PatchOperation
https://github.com/MinecraftForge/ForgeGradle/blob/a74f4b155d3c41f495e4e03398ead9a95ef831f8/src/userdev/java/net/minecraftforge/gradle/userdev/MinecraftUserRepo.java#L1033-L1044