Mac's HFS+ folds concatentations of ".git" and ignorable Unicode
characters [1] to ".git" [2]. Hence we need to disallow all names which
could potentially be a shortname for ".git". Example: in an empty
directory create a folder ".g\U+200Cit". Now you can't create another
folder ".git".
The following characters are ignorable Unicode which are ignored on
HFS+:
unicode hex name
-------------------------------------------------
U+200C 0xe2808c ZERO WIDTH NON-JOINER
U+200D 0xe2808d ZERO WIDTH JOINER
U+200E 0xe2808e LEFT-TO-RIGHT MARK
U+200F 0xe2808f RIGHT-TO-LEFT MARK
U+202A 0xe280aa LEFT-TO-RIGHT EMBEDDING
U+202B 0xe280ab RIGHT-TO-LEFT EMBEDDING
U+202C 0xe280ac POP DIRECTIONAL FORMATTING
U+202D 0xe280ad LEFT-TO-RIGHT OVERRIDE
U+202E 0xe280ae RIGHT-TO-LEFT OVERRIDE
U+206A 0xe281aa INHIBIT SYMMETRIC SWAPPING
U+206B 0xe281ab ACTIVATE SYMMETRIC SWAPPING
U+206C 0xe281ac INHIBIT ARABIC FORM SHAPING
U+206D 0xe281ad ACTIVATE ARABIC FORM SHAPING
U+206E 0xe281ae NATIONAL DIGIT SHAPES
U+206F 0xe281af NOMINAL DIGIT SHAPES
U+FEFF 0xefbbbf ZERO WIDTH NO-BREAK SPACE
[1] http://www.unicode.org/versions/Unicode7.0.0/ch05.pdf#G40025http://www.unicode.org/reports/tr31/#Layout_and_Format_Control_Characters
[2] http://dubeiko.com/development/FileSystems/HFSPLUS/tn1150.html#UnicodeSubtleties
Change-Id: Ib6a1dd090b2649bdd8ec16387c994ed29de2860d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
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