merge-tree: fix where two branches share no changes

[git.git] / diff.c

diff --git a/diff.c b/diff.c
index 230c310952f0296d195c32fbe18b26b279b3fd54..57e1212fbcc9783d3fdbd248762247d8e0efd886 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1600,6 +1600,7 @@ static void builtin_diff(const char *name_a,
                         struct diff_filespec *one,
                         struct diff_filespec *two,
                         const char *xfrm_msg,
+                        int must_show_header,
                         struct diff_options *o,
                         int complete_rewrite)
 {
@@ -1651,16 +1652,19 @@ static void builtin_diff(const char *name_a,
                strbuf_addf(&header, "%snew file mode %06o%s\n", set, two->mode, reset);
                if (xfrm_msg)
                        strbuf_addstr(&header, xfrm_msg);
+               must_show_header = 1;
        }
        else if (lbl[1][0] == '/') {
                strbuf_addf(&header, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
                if (xfrm_msg)
                        strbuf_addstr(&header, xfrm_msg);
+               must_show_header = 1;
        }
        else {
                if (one->mode != two->mode) {
                        strbuf_addf(&header, "%sold mode %06o%s\n", set, one->mode, reset);
                        strbuf_addf(&header, "%snew mode %06o%s\n", set, two->mode, reset);
+                       must_show_header = 1;
                }
                if (xfrm_msg)
                        strbuf_addstr(&header, xfrm_msg);
@@ -1691,8 +1695,11 @@ static void builtin_diff(const char *name_a,
              (diff_filespec_is_binary(two) && !textconv_two) )) {
                /* Quite common confusing case */
                if (mf1.size == mf2.size &&
-                   !memcmp(mf1.ptr, mf2.ptr, mf1.size))
+                   !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
+                       if (must_show_header)
+                               fprintf(o->file, "%s", header.buf);
                        goto free_ab_and_return;
+               }
                fprintf(o->file, "%s", header.buf);
                strbuf_reset(&header);
                if (DIFF_OPT_TST(o, BINARY))
@@ -1710,7 +1717,7 @@ static void builtin_diff(const char *name_a,
                struct emit_callback ecbdata;
                const struct userdiff_funcname *pe;
 
-               if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS)) {
+               if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
                        fprintf(o->file, "%s", header.buf);
                        strbuf_reset(&header);
                }
@@ -2320,11 +2327,13 @@ static void fill_metainfo(struct strbuf *msg,
                          struct diff_filespec *two,
                          struct diff_options *o,
                          struct diff_filepair *p,
+                         int *must_show_header,
                          int use_color)
 {
        const char *set = diff_get_color(use_color, DIFF_METAINFO);
        const char *reset = diff_get_color(use_color, DIFF_RESET);
 
+       *must_show_header = 1;
        strbuf_init(msg, PATH_MAX * 2 + 300);
        switch (p->status) {
        case DIFF_STATUS_COPIED:
@@ -2353,8 +2362,7 @@ static void fill_metainfo(struct strbuf *msg,
                }
                /* fallthru */
        default:
-               /* nothing */
-               ;
+               *must_show_header = 0;
        }
        if (one && two && hashcmp(one->sha1, two->sha1)) {
                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
@@ -2386,6 +2394,7 @@ static void run_diff_cmd(const char *pgm,
 {
        const char *xfrm_msg = NULL;
        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
+       int must_show_header = 0;
 
        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
                pgm = NULL;
@@ -2401,6 +2410,7 @@ static void run_diff_cmd(const char *pgm,
                 * external diff driver
                 */
                fill_metainfo(msg, name, other, one, two, o, p,
+                             &must_show_header,
                              DIFF_OPT_TST(o, COLOR_DIFF) && !pgm);
                xfrm_msg = msg->len ? msg->buf : NULL;
        }
@@ -2412,7 +2422,8 @@ static void run_diff_cmd(const char *pgm,
        }
        if (one && two)
                builtin_diff(name, other ? other : name,
-                            one, two, xfrm_msg, o, complete_rewrite);
+                            one, two, xfrm_msg, must_show_header,
+                            o, complete_rewrite);
        else
                fprintf(o->file, "* Unmerged path %s\n", name);
 }