log: add --show-linear-break to help see non-linear history

Option explanation is in rev-list-options.txt. The interaction with -z
is left undecided.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 03533af..1261ac0 100644 (file)
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -750,6 +750,13 @@ This enables parent rewriting, see 'History Simplification' below.
 This implies the `--topo-order` option by default, but the
 `--date-order` option may also be specified.
 
+--show-linear-break[=<barrier>]::
+       When --graph is not used, all history branches are flattened
+       which can make it hard to see that the two consecutive commits
+       do not belong to a linear branch. This option puts a barrier
+       in between them in that case. If `<barrier>` is specified, it
+       is the string that will be shown instead of the default one.
+
 ifdef::git-rev-list[]
 --count::
        Print a number stating how many commits would have been

diff --git a/log-tree.c b/log-tree.c
index 08970bf..17862f6 100644 (file)
--- a/log-tree.c
+++ b/log-tree.c
@@ -805,12 +805,16 @@ int log_tree_commit(struct rev_info *opt, struct commit *commit)
        if (opt->line_level_traverse)
                return line_log_print(opt, commit);
 
+       if (opt->track_linear && !opt->linear && !opt->reverse_output_stage)
+               printf("\n%s\n", opt->break_bar);
        shown = log_tree_diff(opt, commit, &log);
        if (!shown && opt->loginfo && opt->always_show_header) {
                log.parent = NULL;
                show_log(opt);
                shown = 1;
        }
+       if (opt->track_linear && !opt->linear && opt->reverse_output_stage)
+               printf("\n%s\n", opt->break_bar);
        opt->loginfo = NULL;
        maybe_flush_or_die(stdout, "stdout");
        return shown;

diff --git a/object.h b/object.h
index 5e30066..ce01142 100644 (file)
--- a/object.h
+++ b/object.h
@@ -28,7 +28,7 @@ struct object_array {
 #define TYPE_BITS   3
 /*
  * object flag allocation:
- * revision.h:      0---------10
+ * revision.h:      0---------10                                26
  * fetch-pack.c:    0---4
  * walker.c:        0-2
  * upload-pack.c:               11----------------19

diff --git a/revision.c b/revision.c
index a68fde6..05b76c7 100644 (file)
--- a/revision.c
+++ b/revision.c
@@ -1832,6 +1832,14 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                revs->notes_opt.use_default_notes = 1;
        } else if (!strcmp(arg, "--show-signature")) {
                revs->show_signature = 1;
+       } else if (!strcmp(arg, "--show-linear-break") ||
+                  starts_with(arg, "--show-linear-break=")) {
+               if (starts_with(arg, "--show-linear-break="))
+                       revs->break_bar = xstrdup(arg + 20);
+               else
+                       revs->break_bar = "                    ..........";
+               revs->track_linear = 1;
+               revs->track_first_time = 1;
        } else if (starts_with(arg, "--show-notes=") ||
                   starts_with(arg, "--notes=")) {
                struct strbuf buf = STRBUF_INIT;
@@ -1955,6 +1963,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
                        unkv[(*unkc)++] = arg;
                return opts;
        }
+       if (revs->graph && revs->track_linear)
+               die("--show-linear-break and --graph are incompatible");
 
        return 1;
 }
@@ -2897,6 +2907,27 @@ enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
        return action;
 }
 
+static void track_linear(struct rev_info *revs, struct commit *commit)
+{
+       if (revs->track_first_time) {
+               revs->linear = 1;
+               revs->track_first_time = 0;
+       } else {
+               struct commit_list *p;
+               for (p = revs->previous_parents; p; p = p->next)
+                       if (p->item == NULL || /* first commit */
+                           !hashcmp(p->item->object.sha1, commit->object.sha1))
+                               break;
+               revs->linear = p != NULL;
+       }
+       if (revs->reverse) {
+               if (revs->linear)
+                       commit->object.flags |= TRACK_LINEAR;
+       }
+       free_commit_list(revs->previous_parents);
+       revs->previous_parents = copy_commit_list(commit->parents);
+}
+
 static struct commit *get_revision_1(struct rev_info *revs)
 {
        if (!revs->commits)
@@ -2936,6 +2967,8 @@ static struct commit *get_revision_1(struct rev_info *revs)
                        die("Failed to simplify parents of commit %s",
                            sha1_to_hex(commit->object.sha1));
                default:
+                       if (revs->track_linear)
+                               track_linear(revs, commit);
                        return commit;
                }
        } while (revs->commits);
@@ -3102,14 +3135,23 @@ struct commit *get_revision(struct rev_info *revs)
                revs->reverse_output_stage = 1;
        }
 
-       if (revs->reverse_output_stage)
-               return pop_commit(&revs->commits);
+       if (revs->reverse_output_stage) {
+               c = pop_commit(&revs->commits);
+               if (revs->track_linear)
+                       revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
+               return c;
+       }
 
        c = get_revision_internal(revs);
        if (c && revs->graph)
                graph_update(revs->graph, c);
-       if (!c)
+       if (!c) {
                free_saved_parents(revs);
+               if (revs->previous_parents) {
+                       free_commit_list(revs->previous_parents);
+                       revs->previous_parents = NULL;
+               }
+       }
        return c;
 }
 

diff --git a/revision.h b/revision.h
index 531fb0d..b8f4bc9 100644 (file)
--- a/revision.h
+++ b/revision.h
@@ -19,7 +19,8 @@
 #define SYMMETRIC_LEFT (1u<<8)
 #define PATCHSAME      (1u<<9)
 #define BOTTOM         (1u<<10)
-#define ALL_REV_FLAGS  ((1u<<11)-1)
+#define TRACK_LINEAR   (1u<<26)
+#define ALL_REV_FLAGS  (((1u<<11)-1) | TRACK_LINEAR)
 
 #define DECORATE_SHORT_REFS    1
 #define DECORATE_FULL_REFS     2
@@ -138,6 +139,10 @@ struct rev_info {
                        preserve_subject:1;
        unsigned int    disable_stdin:1;
        unsigned int    leak_pending:1;
+       /* --show-linear-break */
+       unsigned int    track_linear:1,
+                       track_first_time:1,
+                       linear:1;
 
        enum date_mode date_mode;
 
@@ -196,6 +201,9 @@ struct rev_info {
 
        /* copies of the parent lists, for --full-diff display */
        struct saved_parents *saved_parents_slab;
+
+       struct commit_list *previous_parents;
+       const char *break_bar;
 };
 
 extern int ref_excluded(struct string_list *, const char *path);