Re: [PATCH] Respect core.autocrlf when preparing temporary files for external diff

> When preparing temporary files for an external diff, the files should be
> handled as if they were worktree files.
> 
> This makes things consistent for the case when one side of the diff was
> found in the current working directory (and therefore creating a temporary
> file could be avoided altogether).
> 
> This fixes msysGit issue 177.
> 
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  diff.c                   |   13 ++++++++++---
>  t/t4020-diff-external.sh |   16 ++++++++++++++++
>  2 files changed, 26 insertions(+), 3 deletions(-)
> 
> diff --git a/diff.c b/diff.c
> index 75d9fab..699ae6a 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -1946,17 +1946,23 @@ void diff_free_filespec_data(struct diff_filespec *s)
>  	s->cnt_data = NULL;
>  }
>  
> -static void prep_temp_blob(struct diff_tempfile *temp,
> +static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
>  			   void *blob,
>  			   unsigned long size,
>  			   const unsigned char *sha1,
>  			   int mode)
>  {
>  	int fd;
> +	struct strbuf buf = STRBUF_INIT;
>  
>  	fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
>  	if (fd < 0)
>  		die("unable to create temp-file: %s", strerror(errno));
> +	if (convert_to_working_tree(path,
> +			(const char *)blob, (size_t)size, &buf)) {
> +		blob = buf.buf;
> +		size = buf.len;
> +	}
>  	if (write_in_full(fd, blob, size) != size)
>  		die("unable to write temp-file");
>  	close(fd);
> @@ -1964,6 +1970,7 @@ static void prep_temp_blob(struct diff_tempfile *temp,
>  	strcpy(temp->hex, sha1_to_hex(sha1));
>  	temp->hex[40] = 0;
>  	sprintf(temp->mode, "%06o", mode);
> +	strbuf_release(&buf);
>  }
>  
>  static struct diff_tempfile *prepare_temp_file(const char *name,
> @@ -2004,7 +2011,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
>  				die("readlink(%s)", name);
>  			if (ret == sizeof(buf))
>  				die("symlink too long: %s", name);
> -			prep_temp_blob(temp, buf, ret,
> +			prep_temp_blob(name, temp, buf, ret,
>  				       (one->sha1_valid ?
>  					one->sha1 : null_sha1),
>  				       (one->sha1_valid ?
> @@ -2030,7 +2037,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
>  	else {
>  		if (diff_populate_filespec(one, 0))
>  			die("cannot read data blob for %s", one->path);
> -		prep_temp_blob(temp, one->data, one->size,
> +		prep_temp_blob(name, temp, one->data, one->size,
>  			       one->sha1, one->mode);
>  	}
>  	return temp;
> diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
> index 281680d..f8c99f1 100755
> --- a/t/t4020-diff-external.sh
> +++ b/t/t4020-diff-external.sh
> @@ -136,4 +136,20 @@ test_expect_success 'GIT_EXTERNAL_DIFF with more than one changed files' '
>  	GIT_EXTERNAL_DIFF=echo git diff
>  '
>  
> +echo "#!$SHELL_PATH" >fake-diff.sh
> +cat >> fake-diff.sh <<\EOF
> +cat $2 >> crlfed.txt
> +EOF
> +chmod a+x fake-diff.sh
> +
> +keep_only_cr () {
> +	tr -dc '\015'
> +}
> +
> +test_expect_success 'external diff with autocrlf = true' '
> +	git config core.autocrlf true &&
> +	GIT_EXTERNAL_DIFF=./fake-diff.sh git diff &&
> +	test $(wc -l < crlfed.txt) = $(cat crlfed.txt | keep_only_cr | wc -c)
> +'
> +
>  test_done