In my bash prompt, $(__git_ps1) is telling me something is wrong, but what?

Question

I've hacked my bash prompt to (in theory) tell me what git branch I'm currently in. But the output indicates that something's wrong:

22:07 (seesaw|REBASE-i) infwb $git branch
* master
  wkg

Here's the relevant code in my .bash_profile file (I'll put a larger chunck of it at the end of this question):

PS1="$GRAY\$(date +%H:%M)\$(__git_ps1) $GREEN\W$YELLOW \$"

As you can see, $(__git_ps1) returns (seesaw|REBASE-i), even though I no longer have a seesaw branch! (I did have one, and it had a rebase problem in relation to my remote seesaw branch on github. I solved the problem, I think, and git branch -r seesaw successfully removed the local copy.)

I'm pretty sure that (seesaw|REBASE-i) is telling me that something is wrong, but I don't know what it is.

Thanks for any suggestions you might have. (chunk of .bash_profile follows)

-------from .bash_profile ---------

## ----- from http://en.newinstance.it/2010/05/23/git-autocompletion-and-enhanced-bash-prompt/
# Set git autocompletion and PS1 integration
if [ -f /usr/local/git/contrib/completion/git-completion.bash ]; then
  . /usr/local/git/contrib/completion/git-completion.bash
fi

if [ -f /opt/local/etc/bash_completion ]; then
    . /opt/local/etc/bash_completion
fi
## ----- end 

GRAY="\[\033[1;30m\]"
YELLOW="\[\033[1;33m\]"
GREEN="\[\033[0;32m\]"

PS1="$GRAY\$(date +%H:%M)\$(__git_ps1) $GREEN\W$YELLOW \$"

----------------

ADDENDUM

@cdhowie and @manojlds, I'm impressed by your git knowledge!

git rebase --abort caused the info to change to (seesaw). Unfortunately, I can't find rebase-merge (or .git) anywhere on my hard disk. I'm on a Mac, which does Weird Things to many FOSS tools. (I did find git itself, at /usr/local/git.) Nothing at /Library/Application Support or ~//Library/Application Support, either.

(still later)

It turns out that everything is all right. Somehow the git rebase --abort caused the seesaw branch to re-appear (I wasn't expecting that!), and the command left me with seesaw as my current branch. From there, I knew what to do.

Answer 1

Based on comments with @cdhowie, I got suspicion that __git_ps1 is handling the git rebase scenario differently. So I looked into the source and found the following lines:

...
if [ -f "$g/rebase-merge/interactive" ]; then
    r="|REBASE-i"
    b="$(cat "$g/rebase-merge/head-name")"
elif [ -d "$g/rebase-merge" ]; then
    r="|REBASE-m"
    b="$(cat "$g/rebase-merge/head-name")"
...

So as long of the .git/rebase-merge exists you will be getting the "wrong" branch, even if you have moved to another branch.

git rebase --abort will fix it. Or delete .git/rebase-merge