[PATCH] Add -B flag to diff-* brothers.

A new diffcore transformation, diffcore-break.c, is introduced.

When the -B flag is given, a patch that represents a complete
rewrite is broken into a deletion followed by a creation.  This
makes it easier to review such a complete rewrite patch.

The -B flag takes the same syntax as the -M and -C flags to
specify the minimum amount of non-source material the resulting
file needs to have to be considered a complete rewrite, and
defaults to 99% if not specified.

As the new test t4008-diff-break-rewrite.sh demonstrates, if a
file is a complete rewrite, it is broken into a delete/create
pair, which can further be subjected to the usual rename
detection if -M or -C is used.  For example, if file0 gets
completely rewritten to make it as if it were rather based on
file1 which itself disappeared, the following happens:

    The original change looks like this:

	file0     --> file0' (quite different from file0)
	file1     --> /dev/null

    After diffcore-break runs, it would become this:

	file0     --> /dev/null
	/dev/null --> file0'
	file1     --> /dev/null

    Then diffcore-rename matches them up:

	file1     --> file0'

The internal score values are finer grained now.  Earlier
maximum of 10000 has been raised to 60000; there is no user
visible changes but there is no reason to waste available bits.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Junio C Hamano
2005-05-30 00:08:37 -07:00
committed by Linus Torvalds
parent 2cd68882ee
commit f345b0a066
13 changed files with 433 additions and 29 deletions

View File

@ -14,6 +14,7 @@ static int diff_setup_opt = 0;
static int diff_score_opt = 0;
static const char *pickaxe = NULL;
static int pickaxe_opts = 0;
static int diff_break_opt = -1;
static const char *header = NULL;
static const char *header_prefix = "";
@ -263,7 +264,8 @@ static int call_diff_flush(void)
{
diffcore_std(0,
detect_rename, diff_score_opt,
pickaxe, pickaxe_opts);
pickaxe, pickaxe_opts,
diff_break_opt);
if (diff_queue_is_empty()) {
diff_flush(DIFF_FORMAT_NO_OUTPUT, 0);
return 0;
@ -523,6 +525,10 @@ int main(int argc, const char **argv)
diff_score_opt = diff_scoreopt_parse(arg);
continue;
}
if (!strncmp(arg, "-B", 2)) {
diff_break_opt = diff_scoreopt_parse(arg);
continue;
}
if (!strcmp(arg, "-z")) {
diff_output_format = DIFF_FORMAT_MACHINE;
continue;