DirectoryExtensions.TryGetDateTime() fails in some cultures

[twest820]

Issue is this function calls DateTime.TryParseExact() with a null format provider. The parse therefore can only succeed if the current culture uses the same separators as the file containing the metadata. From a quick review it looks to me like the intent is to perform invariant parsing, in which case the fix would be to pass CultureInfo.InvariantCulture rather than null.

Workaround is to reimplement the method's code. Personally, I hit this on Arabic so setting CultureInfo.CurrentCulture = CultureInfo.GetCultureInfo("ar") on a test thread should provide repro.

[drewnoakes]

On the general topic of locale sensitivity, we should enable and review these diagnostics:

metadata-extractor-dotnet/.editorconfig

Lines 225 to 228 in 9789ad9

	# TODO review these diagnostics as many/all are probably valid
	dotnet_diagnostic.CA1304.severity = none # Method behaviour depends upon user's locale
	dotnet_diagnostic.CA1305.severity = none # Method behaviour depends upon user's locale
	dotnet_diagnostic.CA1307.severity = none # Method behaviour depends upon user's locale