Daniel Barkalow <barkalow@xxxxxxxxxxxx> writes:
> Actually, this weekend I was trying to cherry-pick the aggregated changes
> to certain files from one branch onto another, and was repeatedly confused
> by the fact that the only available diffs are backwards and there're no
> clues in the output. (That is, you can't get the difference between (---)
> the {index,working tree} and (+++) some commit, and when you've done "git
> diff messy", the resulting diff doesn't give any clues that you're
> deciding whether to add the - lines and remove the + lines.)
I do not know if I like the end result, but here is a patch to make the
traditional a/ and b/ prefix more mnemonic.
A lot of existing tests and documentation need to be updated, if we were
to do this, though. The first test to fail is t1200-tutorial.sh.
Obviously not tested except for creating this patch that pretends to be a
format-patch output. You can tell that I just did this only in the work
tree now.
-- >8 --
diff: vary default prefix depending on what are compared
This implements Daniel's idea to indicate what are compared by using
prefix different from the traditional a/ and b/ in the textual diff
header:
"git diff" compares the (i)ndex and the (w)ork tree;
"git diff HEAD" compares a (c)ommit and the (w)ork tree;
"git diff --cached" compares a (c)ommit and the (i)ndex;
"git diff HEAD:f /tmp/f" compares an (o)bject and (w)ork tree.
Because these mnemonics now have meanings, they are swapped when reverse
diff is in effect.
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
builtin-diff.c | 2 ++
diff-lib.c | 3 +++
diff.c | 38 +++++++++++++++++++++++++++++++-------
diff.h | 2 ++
4 files changed, 38 insertions(+), 7 deletions(-)
diff --git i/builtin-diff.c w/builtin-diff.c
index 7ffea97..ecec753 100644
--- i/builtin-diff.c
+++ w/builtin-diff.c
@@ -74,6 +74,8 @@ static int builtin_diff_b_f(struct rev_info *revs,
if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
die("'%s': not a regular file or symlink", path);
+ diff_set_default_prefix(&revs->diffopt, "o/", "w/");
+
if (blob[0].mode == S_IFINVALID)
blob[0].mode = canon_mode(st.st_mode);
diff --git i/diff-lib.c w/diff-lib.c
index e7eaff9..969f8c1 100644
--- i/diff-lib.c
+++ w/diff-lib.c
@@ -63,6 +63,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
? CE_MATCH_RACY_IS_DIRTY : 0);
char symcache[PATH_MAX];
+ diff_set_default_prefix(&revs->diffopt, "i/", "w/");
+
if (diff_unmerged_stage < 0)
diff_unmerged_stage = 2;
entries = active_nr;
@@ -469,6 +471,7 @@ int run_diff_index(struct rev_info *revs, int cached)
if (unpack_trees(1, &t, &opts))
exit(128);
+ diff_set_default_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
diffcore_std(&revs->diffopt);
diff_flush(&revs->diffopt);
return 0;
diff --git i/diff.c w/diff.c
index bf5d5f1..1c518c6 100644
--- i/diff.c
+++ w/diff.c
@@ -305,6 +305,15 @@ static void emit_rewrite_diff(const char *name_a,
const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
const char *reset = diff_get_color(color_diff, DIFF_RESET);
static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
+ const char *a_prefix, *b_prefix;
+
+ if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
+ a_prefix = o->b_prefix;
+ b_prefix = o->a_prefix;
+ } else {
+ a_prefix = o->a_prefix;
+ b_prefix = o->b_prefix;
+ }
name_a += (*name_a == '/');
name_b += (*name_b == '/');
@@ -313,8 +322,8 @@ static void emit_rewrite_diff(const char *name_a,
strbuf_reset(&a_name);
strbuf_reset(&b_name);
- quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
- quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
+ quote_two_c_style(&a_name, a_prefix, name_a, 0);
+ quote_two_c_style(&b_name, b_prefix, name_b, 0);
diff_populate_filespec(one, 0);
diff_populate_filespec(two, 0);
@@ -1424,6 +1433,14 @@ static const char *diff_funcname_pattern(struct diff_filespec *one)
return NULL;
}
+void diff_set_default_prefix(struct diff_options *options, const char *a, const char *b)
+{
+ if (!options->a_prefix)
+ options->a_prefix = a;
+ if (!options->b_prefix)
+ options->b_prefix = b;
+}
+
static void builtin_diff(const char *name_a,
const char *name_b,
struct diff_filespec *one,
@@ -1437,9 +1454,19 @@ static void builtin_diff(const char *name_a,
char *a_one, *b_two;
const char *set = diff_get_color_opt(o, DIFF_METAINFO);
const char *reset = diff_get_color_opt(o, DIFF_RESET);
+ const char *a_prefix, *b_prefix;
- a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
- b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
+ diff_set_default_prefix(o, "a/", "b/");
+ if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
+ a_prefix = o->b_prefix;
+ b_prefix = o->a_prefix;
+ } else {
+ a_prefix = o->a_prefix;
+ b_prefix = o->b_prefix;
+ }
+
+ a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
+ b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
@@ -2298,9 +2325,6 @@ void diff_setup(struct diff_options *options)
else
DIFF_OPT_CLR(options, COLOR_DIFF);
options->detect_rename = diff_detect_rename_default;
-
- options->a_prefix = "a/";
- options->b_prefix = "b/";
}
int diff_setup_done(struct diff_options *options)
diff --git i/diff.h w/diff.h
index 50fb5dd..5782fef 100644
--- i/diff.h
+++ w/diff.h
@@ -160,6 +160,8 @@ extern void diff_tree_combined(const unsigned char *sha1, const unsigned char pa
extern void diff_tree_combined_merge(const unsigned char *sha1, int, struct rev_info *);
+void diff_set_default_prefix(struct diff_options *options, const char *a, const char *b);
+
extern void diff_addremove(struct diff_options *,
int addremove,
unsigned mode,
--
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