git-diff.txt: add section "output format" describing the diff formats

diff --git a/revision.c b/revision.c
index 33d092c3c4b4c08fb6f39228e464219df4cb4f1c..48756b5d4466d06123922573e4330fc4344c1dcb 100644 (file)
--- a/revision.c
+++ b/revision.c
@@ -1209,8 +1209,6 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 
                        opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
                        if (opts > 0) {
-                               if (strcmp(argv[i], "-z"))
-                                       revs->diff = 1;
                                i += opts - 1;
                                continue;
                        }
@@ -1254,6 +1252,14 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
                add_pending_object_with_mode(revs, object, def, mode);
        }
 
+       /* Did the user ask for any diff output? Run the diff! */
+       if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
+               revs->diff = 1;
+
+       /* Pickaxe and rename following needs diffs */
+       if (revs->diffopt.pickaxe || revs->diffopt.follow_renames)
+               revs->diff = 1;
+
        if (revs->topo_order)
                revs->limited = 1;