Testing for uncommitted changes in mercurial

Question

What's the best way to check in script if there're uncommitted changes in mercurial's working tree.

(the way I would with git diff --quiet in git)

Answer 1

In mercurial 1.4 and later you can use the summary command, which gives output like this when changes exist:

$ hg summary
parent: 0:ad218537bdef tip
 commited
branch: default
commit: 1 modified
update: (current)

and this post-commit:

$ hg summary
parent: 1:ef93d692f646 tip
 sfsdf
branch: default
commit: (clean)
update: (current)

Alternately, you could install the prompt extension and do something like this:

$ hg prompt '{status}'

which will output a ! or ? or nothing as appropriate.

Both of those, of course, are just alternate text outputs. I couldn't find anything that used the exit code directly, but since $? checks the last command in a pipe you could do?

hg summary | grep -q 'commit: (clean)'

which will set $? non-zero if any changes are uncommitted:

$ hg summary | grep -q 'commit: (clean)' ; echo $?
0
$ echo more >> that 
$ hg summary | grep -q 'commit: (clean)' ; echo $?
1