show-branch: make the current branch and merge commits stand out.

This changes the character used to mark the commits that is on the
branch from '+' to '*' for the current branch, to make it stand out.
Also we show '-' for merge commits.

When you have a handful branches with relatively long diversion, it
is easier to see which one is the current branch this way.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-show-branch.txt

@@ -81,21 +81,22 @@ OUTPUT
 ------
 Given N <references>, the first N lines are the one-line
 description from their commit message.  The branch head that is
-pointed at by $GIT_DIR/HEAD is prefixed with an asterisk '*'
-character while other heads are prefixed with a '!' character.
+pointed at by $GIT_DIR/HEAD is prefixed with an asterisk `*`
+character while other heads are prefixed with a `!` character.
 
 Following these N lines, one-line log for each commit is
 displayed, indented N places.  If a commit is on the I-th
-branch, the I-th indentation character shows a '+' sign;
-otherwise it shows a space.  Each commit shows a short name that
+branch, the I-th indentation character shows a `+` sign;
+otherwise it shows a space.  Merge commits are denoted by
+a `-` sign.  Each commit shows a short name that
 can be used as an extended SHA1 to name that commit.
 
 The following example shows three branches, "master", "fixes"
 and "mhf":
 
 ------------------------------------------------
 $ git show-branch master fixes mhf
-! [master] Add 'git show-branch'.
+* [master] Add 'git show-branch'.
  ! [fixes] Introduce "reset type" flag to "git reset"
   ! [mhf] Allow "+remote:local" refspec to cause --force when fetching.
 ---
@@ -109,13 +110,13 @@ $ git show-branch master fixes mhf
   + [mhf~6] Retire git-parse-remote.
   + [mhf~7] Multi-head fetch.
   + [mhf~8] Start adding the $GIT_DIR/remotes/ support.
-+++ [master] Add 'git show-branch'.
+*++ [master] Add 'git show-branch'.
 ------------------------------------------------
 
 These three branches all forked from a common commit, [master],
 whose commit message is "Add 'git show-branch'.  "fixes" branch
 adds one commit 'Introduce "reset type"'.  "mhf" branch has many
-other commits.
+other commits.  The current branch is "master".
 
 
 EXAMPLE

Documentation/howto/revert-branch-rebase.txt

@@ -32,16 +32,16 @@ merge introduced 5 commits or so:
 
 ------------------------------------------------
 $ git show-branch --more=4 master master^2 | head
-! [master] Merge refs/heads/portable from http://www.cs.berkeley....
+* [master] Merge refs/heads/portable from http://www.cs.berkeley....
  ! [master^2] Replace C99 array initializers with code.
 --
-+  [master] Merge refs/heads/portable from http://www.cs.berkeley....
-++ [master^2] Replace C99 array initializers with code.
-++ [master^2~1] Replace unsetenv() and setenv() with older putenv().
-++ [master^2~2] Include sys/time.h in daemon.c.
-++ [master^2~3] Fix ?: statements.
-++ [master^2~4] Replace zero-length array decls with [].
-+  [master~1] tutorial note about git branch
+-  [master] Merge refs/heads/portable from http://www.cs.berkeley....
+*+ [master^2] Replace C99 array initializers with code.
+*+ [master^2~1] Replace unsetenv() and setenv() with older putenv().
+*+ [master^2~2] Include sys/time.h in daemon.c.
+*+ [master^2~3] Fix ?: statements.
+*+ [master^2~4] Replace zero-length array decls with [].
+*  [master~1] tutorial note about git branch
 ------------------------------------------------
 
 The '--more=4' above means "after we reach the merge base of refs,
@@ -193,8 +193,8 @@ $ git show-branch --more=1 master pu rc
  +  [pu~4] Document "git cherry-pick" and "git revert"
  +  [pu~5] Remove git-apply-patch-script.
  +  [pu~6] Redo "revert" using three-way merge machinery.
-  + [rc] Merge refs/heads/master from .
-+++ [master] Revert "Replace zero-length array decls with []."
-  + [rc~1] Merge refs/heads/master from .
-+++ [master~1] Merge refs/heads/portable from http://www.cs.berkeley....
+  - [rc] Merge refs/heads/master from .
+++* [master] Revert "Replace zero-length array decls with []."
+  - [rc~1] Merge refs/heads/master from .
+... [master~1] Merge refs/heads/portable from http://www.cs.berkeley....
 ------------------------------------------------

Documentation/tutorial.txt

@@ -968,8 +968,8 @@ $ git show-branch master mybranch
 * [master] Merge work in mybranch
  ! [mybranch] Some work.
 --
-+  [master] Merge work in mybranch
-++ [mybranch] Some work.
+-  [master] Merge work in mybranch
+*+ [mybranch] Some work.
 ------------------------------------------------
 
 The first two lines indicate that it is showing the two branches
@@ -979,7 +979,8 @@ top-of-the-tree commits, you are currently on `master` branch
 the later output lines is used to show commits contained in the
 `master` branch, and the second column for the `mybranch`
 branch. Three commits are shown along with their log messages.
-All of them have plus `+` characters in the first column, which
+All of them have non blank characters in the first column (`*`
+shows an ordinary commit on the current branch, `.` is a merge commit), which
 means they are now part of the `master` branch. Only the "Some
 work" commit has the plus `+` character in the second column,
 because `mybranch` has not been merged to incorporate these
@@ -1024,7 +1025,7 @@ $ git show-branch master mybranch
 ! [master] Merge work in mybranch
  * [mybranch] Merge work in mybranch
 --
-++ [master] Merge work in mybranch
+-- [master] Merge work in mybranch
 ------------------------------------------------
 
 
@@ -1199,9 +1200,9 @@ $ git show-branch --more=3 master mybranch
 ! [master] Merge work in mybranch
  * [mybranch] Merge work in mybranch
 --
-++ [master] Merge work in mybranch
-++ [master^2] Some work.
-++ [master^] Some fun.
+-- [master] Merge work in mybranch
++* [master^2] Some work.
++* [master^] Some fun.
 ------------
 
 Remember, before running `git merge`, our `master` head was at
@@ -1223,8 +1224,8 @@ $ git show-branch
  ! [mybranch] Some work.
 --
  + [mybranch] Some work.
-+  [master] Some fun.
-++ [mybranch^] New day.
+*  [master] Some fun.
+*+ [mybranch^] New day.
 ------------
 
 Now we are ready to experiment with the merge by hand.
@@ -1743,8 +1744,8 @@ $ git show-branch
  +  [diff-fix] Fix rename detection.
  +  [diff-fix~1] Better common substring algorithm.
 +   [commit-fix] Fix commit message normalization.
-  + [master] Release candidate #1
-+++ [diff-fix~2] Pretty-print messages.
+  * [master] Release candidate #1
+++* [diff-fix~2] Pretty-print messages.
 ------------
 
 Both fixes are tested well, and at this point, you want to merge
@@ -1764,13 +1765,13 @@ $ git show-branch
  ! [diff-fix] Fix rename detection.
   * [master] Merge fix in commit-fix
 ---
-  + [master] Merge fix in commit-fix
-+ + [commit-fix] Fix commit message normalization.
-  + [master~1] Merge fix in diff-fix
- ++ [diff-fix] Fix rename detection.
- ++ [diff-fix~1] Better common substring algorithm.
-  + [master~2] Release candidate #1
-+++ [master~3] Pretty-print messages.
+  - [master] Merge fix in commit-fix
++ * [commit-fix] Fix commit message normalization.
+  - [master~1] Merge fix in diff-fix
+ +* [diff-fix] Fix rename detection.
+ +* [diff-fix~1] Better common substring algorithm.
+  * [master~2] Release candidate #1
+++* [master~3] Pretty-print messages.
 ------------
 
 However, there is no particular reason to merge in one branch
@@ -1797,12 +1798,12 @@ $ git show-branch
  ! [diff-fix] Fix rename detection.
   * [master] Octopus merge of branches 'diff-fix' and 'commit-fix'
 ---
-  + [master] Octopus merge of branches 'diff-fix' and 'commit-fix'
-+ + [commit-fix] Fix commit message normalization.
- ++ [diff-fix] Fix rename detection.
- ++ [diff-fix~1] Better common substring algorithm.
-  + [master~1] Release candidate #1
-+++ [master~2] Pretty-print messages.
+  - [master] Octopus merge of branches 'diff-fix' and 'commit-fix'
++ * [commit-fix] Fix commit message normalization.
+ +* [diff-fix] Fix rename detection.
+ +* [diff-fix~1] Better common substring algorithm.
+  * [master~1] Release candidate #1
+++* [master~2] Pretty-print messages.
 ------------
 
 Note that you should not do Octopus because you can.  An octopus

show-branch.c

@@ -545,6 +545,7 @@ int main(int ac, char **av)
 	int sha1_name = 0;
 	int shown_merge_point = 0;
 	int topo_order = 0;
+	int head_at = -1;
 
 	git_config(git_show_branch_config);
 	setup_git_directory();
@@ -675,6 +676,8 @@ int main(int ac, char **av)
 			}
 			/* header lines never need name */
 			show_one_commit(rev[i], 1);
+			if (is_head)
+				head_at = i;
 		}
 		if (0 <= extra) {
 			for (i = 0; i < num_rev; i++)
@@ -703,9 +706,19 @@ int main(int ac, char **av)
 		shown_merge_point |= ((this_flag & all_revs) == all_revs);
 
 		if (1 < num_rev) {
-			for (i = 0; i < num_rev; i++)
-				putchar((this_flag & (1u << (i + REV_SHIFT)))
-					? '+' : ' ');
+			int is_merge = !!(commit->parents && commit->parents->next);
+			for (i = 0; i < num_rev; i++) {
+				int mark;
+				if (!(this_flag & (1u << (i + REV_SHIFT))))
+					mark = ' ';
+				else if (is_merge)
+					mark = '-';
+				else if (i == head_at)
+					mark = '*';
+				else
+					mark = '+';
+				putchar(mark);
+			}
 			putchar(' ');
 		}
 		show_one_commit(commit, no_name);

t/t1200-tutorial.sh

@@ -118,8 +118,8 @@ cat > show-branch.expect << EOF
 * [master] Merged "mybranch" changes.
  ! [mybranch] Some work.
 --
-+  [master] Merged "mybranch" changes.
-++ [mybranch] Some work.
+-  [master] Merged "mybranch" changes.
+*+ [mybranch] Some work.
 EOF
 
 git show-branch --topo-order master mybranch > show-branch.output
@@ -142,7 +142,7 @@ cat > show-branch2.expect << EOF
 ! [master] Merged "mybranch" changes.
  * [mybranch] Merged "mybranch" changes.
 --
-++ [master] Merged "mybranch" changes.
+-- [master] Merged "mybranch" changes.
 EOF
 
 git show-branch --topo-order master mybranch > show-branch2.output