Mercurial Subrepositories: Prevent accidental recursive commits and pushes

Question

I work on a team where we have a code in a mercurial repository with several subrepositories:

main/
main/subrepo1/
main/subrepo1/subrepo2/

The default behavior of Mercurial is that when a hg commit is performed in "main", any outstanding changes in the subrepositories "subrepo1" and "subrepo2" will also be committed. Similarly, when "main" is pushed, any outgoing commits in "subrepo1" and "subrepo2" will also be pushed.

We find that people frequently inadvertently commit and push changes in their subrepositories (because they forgot they had made changes, and hg status by default does not show recursive changes). We also find that such global commits / pushes are almost always accidental in our team.

Mercurial 1.7 recently improved the situation with hg status -S and hg outgoing -S, which show changes in subrepositories; but still, this requires people to be paying attention.

Is there a way in Mercurial to make hg commit and hg push abort if there are changes/commits in subrepostories that would otherwise be committed/pushed?

Answer 1

Mercurial 2.0 automatically prevents you from committing subrepositories unless you manually specify the --subrepos (or, alternatively, -S) argument to commit.

For example, you try to perform a commit while there are pending changes in a subrepository, you get the following message:

# hg commit -m 'change main repo'
abort: uncommitted changes in subrepo hello
(use --subrepos for recursive commit)

You can successfully perform the commit, however, by adding --subrepos to the command:

# hg commit --subrepos -m 'commit subrepos'
committing subrepository hello

Some things to still be careful about: If you have changed the revision a subrepository is currently at, but not the contents of the subrepository, Mercurial will happily commit the version change without the --subrepos flag. Further, recursive pushes are still performed without warning.

Answer 2

May be a pre-commit hook (not precommit) could do the hg status -S for you, and block the commit if it detects any changes?

Answer 3

One notion is to use URLs to which you have read-only access in your .hgsub files. Then when you do actually want to push in the subrepo you can just cd into it and do a hg push THE_READ_WRITE_URL.

Answer 4

One possible solution, using VonC's "pre-commit" idea.

Setup two scripts; the first check_subrepo_commit.sh:

#!/bin/bash

# If the environment variable "SUBREPO" is set, allow changes.
[ "x$SUBREPO" != "x" ] && exit 0

# Otherwise, ensure that subrepositories have not changed.
LOCAL_CHANGES=`hg status -a -m`
GLOBAL_CHANGES=`hg status -S -a -m`
if [ "x${LOCAL_CHANGES}" != "x$GLOBAL_CHANGES" ]; then
    echo "Subrepository changes exist!"
    exit 1
fi
exit 0

The second, check_subrepo_push.sh:

#!/bin/bash

# If the environment variable "SUBREPO" is set, allow changes.
[ "x$SUBREPO" != "x" ] && exit 0

# Otherwise, ensure that subrepositories have not changed.
LOCAL_CHANGES=`hg outgoing | grep '^changeset:'`
GLOBAL_CHANGES=`hg outgoing -S | grep '^changeset:'`
if [ "x${LOCAL_CHANGES}" != "x$GLOBAL_CHANGES" ]; then
    echo "Global changes exist!"
    exit 1
fi
exit 0

Add the following to your .hgrc:

[hooks]
pre-commit.subrepo = check_subrepo_commit.sh
pre-push.subrepo = check_subrepo_push.sh

By default, hg push and hg commit will abort if there are outstanding changes in subrepositories. Running a command like so:

SUBREPO=1 hg commit

will override the check, allowing you to perform the global commit/push if you really want to.

Answer 5

Since Mercurial 1.8 there is a configuration setting that disables recursive commits. In the parent repositories .hg/hgrc you can add:

[ui]
commitsubrepos = no

If a commit in the parent repository finds uncommitted changes in a subrepository the whole commit is aborted, instead of silently committing the subrepositories.