Unified Repos

Setting up the repo

Set up your ssh key yourself
Install Mercurial 3.2 or higher
Make a copy of your .hgrc file for safekeeping and delete the original
hg clone https://hg.mozilla.org/mozilla-central
cd mozilla-central
./mach mercurial-setup

Configure mercurial as desired
The following will pull all (or at least most) of the branches sheriffs need to have on hand:

hg pull inbound && hg pull b2ginbound && hg pull fx-team && hg pull aurora && hg pull beta && hg pull esr31 && hg pull b2g34 && hg pull b2g32 && hg pull b2g30

If you need other branches, you can find their names in the firefoxtree extension source.

You should now have everything set up for proper use!

Maybe rename the folder from "mozilla-central" to "unifiedrepo" or something to make it clear it's more than just mozilla-central?

The `hg fxheads` command should list references to each of the relevant branch names, and the current revision and commit message for each.

With bug 1116861 landed in version-control-tools, you can now use the following commands to pull from groups of repositories with a single command:

hg pull fxtrees # this will pull from all branches listed with the fxheads command
hg pull integration # this will pull from the mozilla-inbound, b2g-inbound, and fx-team branches
hg pull releases # this will pull from pretty much every release branch (FYI: including old, unused branches)

Merges

This assumes you have your unified repo all set up so that `hg fxheads` lists each of central, b2ginbound, fx-team, and inbound.

To merge a specific non-tip <revision> from mozilla-inbound to mozilla-central:

hg pull central
hg pull inbound
hg up central
hg merge -r <revision>
hg commit -m "Merge mozilla-inbound to mozilla-central a=merge"
hg push -r . central

To merge mozilla-central into mozilla-inbound:

hg pull central
hg pull inbound
hg up inbound
hg merge central
hg commit -m "Merge mozilla-central to mozilla-inbound a=merge"
hg push -r . inbound

If the `hg merge central` command results in "abort: nothing to merge", you should instead use `hg update -r <mozilla-central's tip revision>` to do a non-merging update, then you can do `hg push -r . inbound` to push it as usual.

Checkin-neededs

This assumes we're checking things in to fx-team. Replace fx-team with another branch name as needed.

Single repository and single set of patches

Update fx-team and prepare for the patches:

hg pull fx-team
hg up fx-team
hg bookmark fx-team-checkins

Import the patches:

hg import https://link.to/correct/checkin-needed.patch
Repeat ^ as needed for all fx-team checkin-needed patches

Verify your outgoing changes:

hg out -r . fx-team

If you haven't lost a push race:

hg push -r . fx-team

If you lost a push race:

hg pull fx-team
hg rebase -d fx-team
hg push -r . fx-team

Delete your no longer needed bookmark:

hg bookmark -d fx-team-checkins

Multiple repositories with a single set of patches each

You can set up multiple sets of patches at once against multiple repositories: Update fx-team

hg pull fx-team && hg up fx-team

Create a bookmark to base your fx-team checkin-needed patches

hg bookmark fxteam-checkins

Import a bunch of patches against fx-team

hg import <patch1>
hg import <patch2>

Update inbound and make a bookmark for inbound patches

hg pull inbound && hg up inbound && hg bookmark inbound-checkins

Import some patches against inbound

hg import <patch3>
hg import <patch4>

See what you'd be pushing to inbound and push it

hg out -r . inbound # this will only show patch3 and patch4
hg push -r . inbound # this only pushes patch3 and patch4
hg bookmark -d inbound-checkins # delete inbound's checkin bookmark as it's not needed

Go back to your fx-team checkins and add another patch to the bookmark, then push it

hg up fxteam-checkins
hg import <patch5>
hg out -r . fx-team # this will be patch1, patch2, and patch5
hg push -r . fx-team
hg bookmark -d fxteam-checkins

Single repository with multiple sets of patches

Or have multiple sets of patches against a single repository: Update fx-team

hg pull fx-team && hg up fx-team

Make the first bookmark/set

hg bookmark fxteam-checkins-1
hg import <patch1>
hg import <patch2>

Make the second set

hg up fx-team && hg bookmark fxteam-checkins-2
hg import <patch3>
hg import <patch4>

See what's going to be pushed in each

hg out -r . fx-team # patch3 and patch4
hg up fxteam-checkins-1 && hg out -r . fx-team # patch1 and patch2

Push the first set

hg push -r . fx-team # pushes patch1 and patch2

Get ready to push the second set

hg up fxteam-checkins-2
hg rebase -d fx-team # Rebase the second set onto the now-pushed first set

And push it

hg push -r . fx-team # pushes patch3 and patch4

Delete the now-unneeded bookmarks

hg bookmark -d fxteam-checkins-1
hg bookmark -d fxteam-checkins-2

Uplifts

If branch-specific patches are posted, follow the checkin-needed instructions above, importing the patches onto the release branch.

If you're uplifting directly from an m-c checkin to aurora:

Pull and update to prepare for the uplifts:

hg pull central
hg pull aurora
hg up aurora

Graft the mc commit and bring up the editor to edit the commit message, adding "a=foo" as needed:

hg graft --edit -r <revision>

Repeat the previous step as needed for all uplifts as needed. Verify the outgoing changes and push:

hg out -r . aurora
hg push -r . aurora

You can graft a range of commits at once if that's easier:

hg graft -r <toprevision>::<bottomrevision>

Read the documentation for graft for further help.

Backouts

Better tools are coming:

The standard backout command makes backing out revisions more difficult than it should, as it won't pre-fill the backout commit message with a bug number:

Copy backout <revision> from treeherder, note the bug <number>, and remember the <reason>
`hg backout -r <revision>`
- This should open up your editor with a completely empty commit message. Type in the backout message like "Backout revision <revision> (bug <number>) for <reason>" (possibly with "CLOSED TREE" in there to get around a closure hook).
`hg push -r . <tree>`

qbackout can probably still be used (assuming you don't use `hg share` to get multiple working directories, as mq doesn't play nice with shared repos):

Copy the backout <revision> from treeherder
`hg qbackout -e -r <revision>`
- This should open up your editor with a pre-formed commit message like "Backed out <revision> (bug <number>)". Add in the <reason> and possibly "CLOSED TREE" to get around a closure hook.
`hg qfin -a && hg push -r . <tree>`

qbackout can also back out a range of commits in a single backout commit:

`hg qbackout -e -s -r <toprevision>:<bottomrevision>`
- This will open your editor with a pre-formed commit message like "Backed out <toprevision>,<anymiddlerevisions>,<bottomrevision> (bug <number>,any other bug <numbers>)". Add in the <reason> and possibly "CLOSED TREE" to get around a closure hook.
`hg qfin -a ** hg push -r . <tree>`

(Omit qbackout's -s flag to back out each individual revision in the range as a separate commit.)

Revert a backout

https://mozilla-version-control-tools.readthedocs.org/en/latest/hgmozilla/common.html#revive-a-commit-that-was-backed-out

Rebasing after losing a push race

This assumes you have commits you're attempting to push to mozilla-inbound when you lose a push race with someone. Change `inbound` to the correct branch name as needed.

hg pull inbound
hg rebase -d inbound
hg push -r . inbound

Recovering from mistakes

WARNING: This will strip out any commits that haven't been pushed to the remote repositories, regardless of what branch/label/tag those commits are on. (So if you have local changes on inbound and run this command to strip something bad on fx-team, both inbound and fx-team will be stripped.) Only do this if you don't care about any of those commits!

hg strip 'not public()'

You may also need to use some combination of the following to get things back to a known-good state:

hg purge # http://mercurial.selenic.com/wiki/PurgeExtension
hg up -C

See what you're about to push

`hg out` without any flags added will show you a LOT of unrelated commits. To see just what you'll be pushing to a given branch, use `hg out -r . <branch>`

hg out -r . inbound
- This will only display the things you're about to push to the inbound branch

View incoming changes

Since your unified repo will likely have all changesets from the various branches pulled locally, `hg in <somebranch> -r <somerev>` will likely not help you see what would be pulled into your current branch from <somebranch> up to that <somerev>. Instead, you can use the following to print out the equivalent. Say you want to see what would be merged onto mozilla-central from b2g-inbound's revision ca142ec8ba0f:

Make sure m-c is fully up to date:

hg pull central
hg up central

Get all of b2g-inbound's changesets:

hg pull b2ginbound

Do a preview of the merge without actually performing the merge:

hg merge -r ca142ec8ba0f -P

This will print out everything on b2g-inbound (up to and including revision ca142ec8ba0f) that is not already on mozilla-central.

See the log for a particular log

hg log -fr [branch]

Extras

hg aliases

I set up the following aliases in my global .hgrc file to make merging things around trunk a little faster:

[alias]
# merge tree $1, revision $2 to central, optionally appending $3 (for "CLOSED TREE", etc)
mergetocentral = !$HG pull central ; $HG up central ; $HG pull $1 ; $HG merge $2 ; $HG commit -m "Merge $1 to central, a=merge $3" ; $HG push -r . central
# merge central tip to tree $1, optionally appending $2 (for "CLOSED TREE", etc)
mergetointegration = !$HG pull central ; $HG pull $1 ; $HG up $1 ; $HG merge central ; $HG commit -m "Merge m-c to $1, a=merge $2" ; $HG push -r . $1

With these set up, I can merge fx-team's revision 04a3d9130aa0 over to mozilla-central with the following command:

hg mergetocentral fx-team 04a3d9130aa0

and then I can merge mozilla-central's tip back to fx-team with the following command:

hg mergetointegration fx-team

This cuts down on a lot of repetitive typing, saving a bit of time.

For merging from reviewboard patches, there's this alias

 rbimport = !hg transplant -e -s https://reviewboard-hg.mozilla.org/gecko -b $1

Then, it's matter of importing the right hash like the following command:

 hg rbimport dd1462ba321db983061b94e30cee92b6bd81e908

Sheriffing/How To/Unified Repos

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