Merge branch 'rs/diff-index-find-copies-harder-optim' into jch

Halve the memory consumed by artificial filepairs created during
"git diff --find-copioes-harder", also making the operation run
faster.

* rs/diff-index-find-copies-harder-optim:
  diff-index: don't queue unchanged filepairs with diff_change()

diff-lib.c

@@ -418,13 +418,12 @@ static int show_modified(struct rev_info *revs,
 	}
 
 	oldmode = old_entry->ce_mode;
-	if (mode == oldmode && oideq(oid, &old_entry->oid) && !dirty_submodule &&
-	    !revs->diffopt.flags.find_copies_harder)
-		return 0;
-
-	diff_change(&revs->diffopt, oldmode, mode,
-		    &old_entry->oid, oid, 1, !is_null_oid(oid),
-		    old_entry->name, 0, dirty_submodule);
+	if (mode != oldmode || !oideq(oid, &old_entry->oid) || dirty_submodule)
+		diff_change(&revs->diffopt, oldmode, mode,
+			    &old_entry->oid, oid, 1, !is_null_oid(oid),
+			    old_entry->name, 0, dirty_submodule);
+	else if (revs->diffopt.flags.find_copies_harder)
+		diff_same(&revs->diffopt, mode, oid, old_entry->name);
 	return 0;
 }
 

diff.c

@@ -7399,6 +7399,26 @@ void diff_change(struct diff_options *options,
 			  concatpath, old_dirty_submodule, new_dirty_submodule);
 }
 
+void diff_same(struct diff_options *options,
+	       unsigned mode,
+	       const struct object_id *oid,
+	       const char *concatpath)
+{
+	struct diff_filespec *one;
+
+	if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
+		return;
+
+	if (options->prefix &&
+	    strncmp(concatpath, options->prefix, options->prefix_length))
+		return;
+
+	one = alloc_filespec(concatpath);
+	fill_filespec(one, oid, 1, mode);
+	one->count++;
+	diff_queue(&diff_queued_diff, one, one);
+}
+
 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
 {
 	struct diff_filepair *pair;

diff.h

@@ -572,6 +572,11 @@ void diff_change(struct diff_options *,
 		 const char *fullpath,
 		 unsigned dirty_submodule1, unsigned dirty_submodule2);
 
+void diff_same(struct diff_options *,
+	       unsigned mode,
+	       const struct object_id *oid,
+	       const char *fullpath);
+
 struct diff_filepair *diff_unmerge(struct diff_options *, const char *path);
 
 void compute_diffstat(struct diff_options *options, struct diffstat_t *diffstat,