This happens on Windows with a diff involving a file rename that removes some spaces in the path from 4 files. Consistently reproducible.
Not sure how else to debug/fix.
arc from : be34693f236f8b3ca7eb5d88c57cfee334439096
libphutil from: ecf3526e557faa185b5d95cab1f27b43f3ab3ed3
(conduit http trace output) ... <<< [6] <conduit> 280,028 us >>> [8] <exec> $ git diff --no-ext-diff --no-textconv --raw "HEAD" -- >>> [9] <exec> $ git ls-files --others --exclude-standard <<< [8] <exec> 766,075 us <<< [9] <exec> 748,074 us >>> [10] <exec> $ git diff-files --name-only <<< [10] <exec> 504,050 us >>> [11] <exec> $ git show -s --format=%H "b1f343cd03eefb58b01e2f264880646c6b5baffc" -- <<< [11] <exec> 396,039 us >>> [12] <exec> $ git branch --no-color <<< [12] <exec> 427,042 us >>> [13] <exec> $ git rev-parse --verify "arcpatch-D2029" <<< [13] <exec> 396,039 us >>> [14] <exec> $ git show -s --format=%H "b1f343cd03eefb58b01e2f264880646c6b5baffc" -- <<< [14] <exec> 413,041 us >>> [15] <exec> $ git checkout -b "arcpatch-D2029" "b1f343cd03eefb58b01e2f264880646c6b5baffc" <<< [15] <exec> 593,060 us Created and checked out branch arcpatch-D2029. >>> [16] <exec> $ git show -s --format=%H "b1f343cd03eefb58b01e2f264880646c6b5baffc" -- <<< [16] <exec> 441,044 us >>> [17] <exec> $ git apply --index --reject -- "C:\Users\USER\AppData\Local\Temp\b5t6tlr33280cc04\528F7C3.tmp" fatal: git apply: bad git-diff - inconsistent old filename on line 264 <<< [17] <exec> 61,006 us Patch Failed! Usage Exception: Unable to apply patch! [2014-09-15 09:57:22] EXCEPTION: (ArcanistUsageException) Unable to apply patch! at [<arcanist>\src\workflow\ArcanistPatchWorkflow.php:671] #0 ArcanistPatchWorkflow::run() called at [<arcanist>\src\workflow\ArcanistPatchWorkflow.php:375] #1 ArcanistPatchWorkflow::run() called at [<arcanist>\scripts\arcanist.php:338]