FileNotFoundException w/ ku-TR.UTF-8

[HJLeee]

Description

Locale change to/from ku-TR.UTF-8 creates FileNotFoundException for TPA when .NET application has ability to detect and update the locale according to the system locale changes.

I/DOTNET_LAUNCHER(23387): Unhandled exception.
I/DOTNET_LAUNCHER(23387): System.IO.FileNotFoundException: Could not load file or assembly 'System.Collections, Version=4.1.2.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
I/DOTNET_LAUNCHER(23387):
I/DOTNET_LAUNCHER(23387): File name: 'System.Collections, Version=4.1.2.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
I/DOTNET_LAUNCHER(23387):    at ElmSharp.Window..ctor(Window parent, String name, WindowType type)
I/DOTNET_LAUNCHER(23387):    at Xamarin.Forms.Platform.Tizen.FormsApplication.OnPreCreate()
I/DOTNET_LAUNCHER(23387):    at Tizen.Applications.CoreBackend.UICoreBackend.OnCreateNative(IntPtr data)
I/DOTNET_LAUNCHER(23387):    at Tizen.Applications.CoreBackend.UICoreBackend.Run(String[] args)
I/DOTNET_LAUNCHER(23387):    at Tizen.Applications.CoreApplication.Run(String[] args)
I/DOTNET_LAUNCHER(23387):    at Tizen.Applications.CoreUIApplication.Run(String[] args)
I/DOTNET_LAUNCHER(23387):    at Alarm.Program.Main(String[] args)
I/DOTNET_LAUNCHER(23387):
I/DOTNET_LAUNCHER(23387):
I/DOTNET_LAUNCHER(23387): onSigabrt called

It's because in some languages like Turkish, i is not converted into I for toupper() call.
https://blog.codinghorror.com/whats-wrong-with-turkey/

Checking for all possible locale in a Tizen device, 16 cases are found.

Culture: az lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: az upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Culture: az-Cyrl lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: az-Cyrl upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Culture: az-Cyrl-AZ lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: az-Cyrl-AZ upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Culture: az-Latn lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: az-Latn upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Culture: az-Latn-AZ lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: az-Latn-AZ upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Culture: tr lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: tr upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Culture: tr-CY lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: tr-CY upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Culture: tr-TR lower: abcdefghijklmnopqrstuvwxyzabcdefghıjklmnopqrstuvwxyz0123456789.
Culture: tr-TR upper: ABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.
Diff: 16

The related code is here.

runtime/src/coreclr/src/binder/inc/applicationcontext.hpp

Lines 37 to 49 in bbd945e

	class SimpleNameToFileNameMapTraits : public NoRemoveSHashTraits< DefaultSHashTraits< SimpleNameToFileNameMapEntry > >
	{
	public:
	typedef PCWSTR key_t;
	static const SimpleNameToFileNameMapEntry Null() { SimpleNameToFileNameMapEntry e; e.m_wszSimpleName = nullptr; return e; }
	static bool IsNull(const SimpleNameToFileNameMapEntry & e) { return e.m_wszSimpleName == nullptr; }
	static key_t GetKey(const SimpleNameToFileNameMapEntry & e)
	{
	key_t key;
	key = e.m_wszSimpleName;
	return key;
	}
	static count_t Hash(const key_t &str) { return HashiString(str); }

runtime/src/coreclr/src/inc/utilcode.h

Lines 2931 to 2940 in 77a3832

	inline ULONG HashiString(LPCWSTR szStr)
	{
	LIMITED_METHOD_CONTRACT;
	ULONG hash = 5381;
	while (*szStr != 0)
	{
	hash = ((hash << 5) + hash) ^ towupper(*szStr);
	szStr++;
	}
	return hash;

The hash function for TPA lookup uses towupper() which is not recommanded to use for unicode characters.
https://www.man7.org/linux/man-pages/man3/towupper.3.html#NOTES

Could it be fixed to use HashString() for TPA lookup or is there a reason for using case insensitive hash function?

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[vitek-karas]

This is very likely the same issue as #37910 which has some more details on possible fixes.

[HJLeee]

Yes it is the same one. Let me participate in #37910. Thank you.