Re: What's the idea of specifying binary=true together with textconv?
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.
Show 17 quoted lines
> 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
Ilya Kantor