fix: Unicode characters stripped from generated file names

[JoonHyuk0331]

Problem

1. Problem.getDefaultName() directly called defaultConversion, which strips all non-ASCII characters via [^0-9a-zA-Z_]. This bypassed the existing fallback chain in getValidFileName that already supports Unicode through specialCharacterFiltering and unicodeWhiteListConversion. As a result, problem names like "한국어 문제 A" became "__A".

2. Space-to-underscore conversion only existed in defaultConversion (step 3 of the fallback chain). Since specialCharacterFiltering (step 1) succeeds on all modern OS, getValidFileName never reached step 3, leaving spaces unconverted in file names.

Root Cause

1-> getDefaultName() called defaultConversion directly instead of going through the getValidFileName fallback chain, making specialCharacterFiltering and unicodeWhiteListConversion effectively dead code for default file name generation.

2-> getValidFileName delegated space handling entirely to defaultConversion, but spaces are valid path characters, so steps 1 and 2 never threw InvalidPathException and step 3 was never reached.

What Changed

File: DefaultFileGenerator.kt

Change: getValidFileName: protected → internal
Why: Allow getDefaultName() to call it via instance without duplicating fallback logic. No subclass overrides this method.

File: problemGatheringDialog.kt

Change: getDefaultName(): defaultConversion(name) → DefaultFileGenerator(project).getValidFileName(name)
Why: Use the proper fallback chain so Unicode characters are preserved

---

File: DefaultFileGenerator.kt

Change: Added name.replace(' ', '_') after fallback chain in getValidFileName
Why: Ensure space-to-underscore conversion applies regardless of which fallback step succeeds

Test

Test by using ./gradlew runIde -PplatformType=PC -PplatformVersion=2025.1

[Pushpavel]

Hi @JoonHyuk0331, great breakdown in the PR. Problem.getDefaultName() is a mistake, we don't need to convert the problem name in showProblemGatheringDialog at all, It anyways is going to be converted based on file extension when the file is getting generated. So, I think just removing Problem.getDefaultName() and using problemNames = MutableList(problems.size) { problems[it].name } should work fine

[JoonHyuk0331]

thx for the review!
I understood, the dialog doesn't need to convert the name at all since getValidFileName handles it during file generation.

I've removed Problem.getDefaultName() entirely and changed the dialog to use problems[it].name directly. Also reverted getValidFileName visibility back to protected since it's no longer called externally.

remaining change:

in DefaultFileGenerator is adding replace(' ', '_') at the end of getValidFileName, so that space-to-underscore conversion applies regardless of which fallback step succeeds (previously it only existed in defaultConversion).
before

after

2.
Since the dialog no longer passes the name through defaultConversion, users can now see the original Unicode problem name as-is in both
before

after

[JoonHyuk0331]

Hi @Pushpavel, I've implemented the requested changes. Could you please review it again? Thanks!

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...pavel/autocp/gather/base/problemGatheringDialog.kt	0.00%	2 Missing ⚠️
...avel/autocp/gather/filegen/DefaultFileGenerator.kt	0.00%	2 Missing ⚠️
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Files with missing lines	Coverage Δ
...pavel/autocp/gather/base/problemGatheringDialog.kt	0.00% <0.00%> (ø)
...avel/autocp/gather/filegen/DefaultFileGenerator.kt	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

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