Re: [PATCH/RFC] diff: Make numstat machine friendly also for renames

Jakub Narebski [off-list ref] writes:

quoted

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The numstat format for rename is now

  added deleted TAB path for "src" TAB path for "dst" LF

or if -z option is used

  added deleted TAB path for "src" NUL NUL path for "dst" NUL

Why two NULs?

That was the only way I could think of to separate pre-image name
from posi-image name for renames. Note that file name might look like
(part of) diffstat line, and there is no 'status' field in the
numstat to mark rename (as there is in "git diff-tree --raw" output).

The --stat format is for human consumption, and --numstat (be it
with -z or without) is for machines, so I am not opposed to a
format change that gives information that is already computed
but currently is hard to parse.  If the format change breaks
existing scripts, we might want to do --numstat-extended,
though...

For example, I do not see a reason not to add "R98" in there.
I.e.

	added deleted status TAB "src" (TAB "dst"){0,1} LF
	added deleted status NUL "src" (NUL "dst"){0,1} NUL

where the dst path is present only when status says it is a
rename/copy, just like the --raw format.

Did you mean --stat here?

No, I did mean --summary.  But that was foolish of me.  I forgot
that it had the same { namepart => namepart } issue.

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@@ -949,11 +955,19 @@ static void show_numstat(struct diffstat_t* data,
 			printf("-\t-\t");
 		else
 			printf("%d\t%d\t", file->added, file->deleted);
-		if (options->line_termination && !file->is_renamed &&
+		if (options->line_termination &&
 		    quote_c_style(file->name, NULL, NULL, 0))
 			quote_c_style(file->name, NULL, stdout, 0);
 		else
 			fputs(file->name, stdout);
+		if (file->is_renamed) {
+			printf("%s", options->line_termination ? "\t" : "\0\0");

It passes "make test".

But you already grepped to make sure this codepath is never
exercised ;-).

What I was hoping you to notice was that printf("%s", "\0\0")
thing.  %s would not even notice that the const char[] literal
is 2 bytes long.