Correctly strip Windows paths from error messages

[Mingun]

This PR correctly strips ..\tests\formats_err\ string from the error messages on Windows, while still strips ../tests/formats_err/ on *nix.

[Mingun]

Honestly, I think it will be meaningful to pass File object to localFileToSpecs, but that method is called also in test generator in https://github.com/kaitai-io/kaitai_struct_tests repository, so I doesn't touch it yet.

[generalmimon]

I don't think we should proceed this way - this PR only works around the effect of the bug instead of addressing its cause. Read kaitai-io/kaitai_struct_tests#124 (comment) again.

Honestly, I think it will be meaningful to pass File object to localFileToSpecs

Nope, that would be a regression because it has the unpleasant consequence described in issue kaitai-io/kaitai_struct#507 (comment) that you are clearly not aware of.

[Mingun]

What in this PR contradicts the information in kaitai-io/kaitai_struct_tests#124 (comment)? If I understand correctly, it is fine to have platform-specific delimiters in paths in error messages. This PR just create the same platform-specific path and strip it from the output. What's wrong with that approach? What bug you mean? Do you have a link to it? I saw kaitai-io/kaitai_struct#507 earlier and having platform-specific delimiters was found to be expected behavior, no?

Even if you think that some bug is exist, it is not the reason to make life harder. If you find the time to fix that bug, you also will able to fix that place too, because you will see new failing tests.

[Mingun]

I'm afraid, that the current solution is the best way to dealing with paths in the most agnostic way. The platform-specific path always could be present in the error message in case of non-existing imports:

[info] - meta_imports_rel2 *** FAILED ***
[info]   [meta_imports_rel_unknown.ksy: /meta/imports/0:
[info]          error: ..\tests\formats_err\unknown_relative_name.ksy (╨Э╨╡ ╤Г╨┤╨░╨╡╤В╤Б╤П ╨╜╨░╨╣╤В╨╕ ╤Г╨║╨░╨╖╨░╨╜╨╜╤Л╨╣ ╤Д╨░╨╣╨╗)
[info]   ]
[info]     did not equal
[info]   [meta_imports_rel_unknown.ksy: /meta/imports/0:
[info]          error: unknown_relative_name.ksy (No such file or directory)
[info]   ] (SimpleMatchers.scala:34)

The ..\tests\formats_err\unknown_relative_name.ksy (Не удается найти указанный файл) is a message from FileNotFoundException which is thrown here and in the general can contains arbitrary string:

kaitai_struct_compiler/jvm/src/main/scala/io/kaitai/struct/formats/JavaKSYParser.scala

Lines 39 to 46 in 2191070

	def fileNameToSpec(yamlFilename: String): ClassSpec = {
	Log.fileOps.info(() => s"reading $yamlFilename...")
	// This complex string of classes is due to the fact that Java's
	// default "FileReader" implementation always uses system locale,
	// which screws up encoding on some systems and screws up reading
	// UTF-8 files with BOM
	val fis = new FileInputStream(yamlFilename)

Current implementation contains OS-dependent path. It is possible to hack the error message, replace that path and rethrow the exception, but it seems too hacky.

I think, that instead of try to keep original paths in the ksc output, ksc can return a dictionary with mapping of provided paths to the actually used strings in messages. That way utilities which want to index JSON with paths should get a normalized path from the dictionary and use it.