On Wed, Sep 27, 2017 at 10:06:25PM +0300, Ilya Kantor wrote: > When textconv is specified, the program is always used for conversion. Not always. It's enabled by default for the git-diff and git-log" porcelain, but not for plumbing commands, nor for git-format-patch (which needs to create a patch that can be applied). And it can be disabled with --no-textconv. > E.g. consider this: > [diff "png"] > textconv = wc > > Even if a png file is ASCII (manually created), wc gets called, and > the result is made of its output. > > So, the question is: why should one specify binary = true together > with textconv? > > There is an example in docs: > [diff "ps"] > textconv = ps2ascii > binary = true > > ...But what binary = true does here? > Even if we remove it, textconv is called for all ps-files. Setting binary=true overrides Git's binary-detection heuristics. When textconv is in effect, those heuristics aren't used at all. But when it's disabled, if you want to make sure a file is marked as binary, it would kick in then. For example: $ git init $ echo fake-binary >foo.png $ echo "*.png diff=png" >.git/info/attributes $ git config diff.png.textconv "sed s/^/converted:/" $ git add . $ git commit -m foo $ git show ... --- /dev/null +++ b/foo.png @@ -0,0 +1 @@ +converted:fake-binary $ git format-patch --stdout -1 ... --- /dev/null +++ b/foo.png @@ -0,0 +1 @@ +fake-binary $ git config diff.png.binary true $ git format-patch --stdout -1 diff --git a/foo.png b/foo.png new file mode 100644 index 0000000000000000000000000000000000000000..96060daf0866dbaf9538b76587f0da801bed4a5f GIT binary patch literal 12 TcmYdG%udx!%FIhFs^kIy9YO?D literal 0 HcmV?d00001 It's a pretty rare corner case where this is useful. After all, if your file really isn't binary, then a text patch is actually preferable. But you could imagine cases where the heuristics are wrong (e.g., a single NUL very far into the file). -Peff
