completion: simplify "current branch" in __git_ps1()

As I very often work on a detached HEAD, I found it pretty confusing
when __git_ps1() said 'some-name'.  Did I create a branch with that name
by mistake, or do I happen to be on a commit with that exact tag?

This patch fixes the issue by enclosing non branch names in a pair of
parentheses when used to substitute %s token in __git_ps1() argument.

It also fixes a small bug where the branch part is left empty when
.git/HEAD is unreadable for whatever reason.  The output now says
"(unknown)".

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index c2f8ea3444f932006fbbf9e4f3490c25d15bfe2e..be591468dbf9314f658721392c5a38a50a4fb6f9 100755 (executable)
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -106,13 +106,14 @@ __git_ps1 ()
                        if [ -f "$g/BISECT_LOG" ]; then
                                r="|BISECTING"
                        fi
-                       if ! b="$(git symbolic-ref HEAD 2>/dev/null)"; then
-                               if ! b="$(git describe --exact-match HEAD 2>/dev/null)"; then
-                                       if [ -r "$g/HEAD" ]; then
-                                               b="$(cut -c1-7 "$g/HEAD")..."
-                                       fi
-                               fi
-                       fi
+
+                       b="$(git symbolic-ref HEAD 2>/dev/null)" || {
+                               b="$(git describe --exact-match HEAD 2>/dev/null)" ||
+                               b="$(cut -c1-7 "$g/HEAD" 2>/dev/null)..." ||
+                               b="unknown"
+
+                               b="($b)"
+                       }
                fi
 
                local w