Mercurial/Tips And Tricks

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This is the page to add your favorite Mercurial tip.

Tips and Tricks

Preparing a local repo for a cws

  • If you want to create a local repo for an existing cws, take care to clone to the milestone of the cws.
hg clone -r <CWS_milestone> <local_prestine copy> <local_cws_repo>
Documentation caution.png If the cws is on DEV300_m60 and you pull it into a local repo that is on DEV300_m61, you will create new heads in the local repo. If you not comfortable in handling multiple heads, then dont do that!

After pulling/merging

  • hg log --follow-first is a convenient way to display your CWS changes at the top of the log.
  • hg log --follow-first -P <original_clone_milestone> will show only the CWS changesets.
  • hg outgoing works as well, of course.

Combined diff which contains exactly the changes of your CWS without anything pulled from master

If your current milestone tag is locally available:

 hg diff -r <current_milestone_tag>

If your current milestone tag is *not* locally available (might happen, see above):

  • search for your last pull/merge from the master with
 hg log -m
  • then
 hg diff -r <second_parent_of_last_master_merge>

Alternatively, if you just did a pull/merge from master:

 hg export --switch-parent tip

Yet alternatively, just do

 hg outgoing <master_repository> -p --template '\n'

Obtain a list of all modules which contain changes

Sometimes it is interesting to know which modules in your CWS actually contain changes. That's quite easy to find out with

 hg out -q -M --template '{files}\n' <master_repository> | tr ' ' \\n | sed "s#/.*##" | sort | uniq

Getting some changesets from another repository

Sometimes changesets from other repositories are needed. To minimize the risk of merge conflicts later use the transplant extension:

  • Note 1: the transplant extension must be enabled in hgrc
  • Note 2: do not use the changeset revision numbers but the changeset hash values (or unique substrings)

e.g. for transplanting the two changesets 1234:fedcba98, 1245:efcd1234 and all changesets between 1256:abcd9876 and 1267:cdab7968 from another repository into the current repository run

 hg transplant -s other_repository fedc efcd abcd:cdab


The default output format of some commands does not suit you? Use styles:

  • hg log --style=compact
  • hg outgoing --style=changelog
  • Or create your own format with the template engine:
    • hg outgoing --template '{date|shortdate} {author|person} {desc}\n' --newest-first

On Windows/cygwin


Depending on the cygwin version, using cygwins hg (and other tools) sometimes fails. TortoiseHg ( can be used as alternative.

To get rid of cygwin's hg rename /usr/bin/hg.

You can decide which ssl support you use in the cygwin shell. If you want to use the ssh-agent then you have to specify the following line in the [ui] section of ~/.hgrc:

ssh = <Windows path to cygwin>\bin\ssh.exe -C

For the graphical interface of TortoiseHg Putty's pageant is the default ssh key provider. TortoiseHg allows easy graphical access to hg repositories within the Windows Explorer.

Accessing repository over ssh

  • If you want to use the ssh client of your Cygwin shell (and also ssh-agent), add the following to the [ui] section of your mercurial.ini:
ssh = ssh -C

Handling multiple heads

Getting rid of multiple heads

When you accidentally created a repo with multiple heads, these are the possibilities to get rid of them:

Merge heads

  • hg merge This is the easiest possibility.
Documentation note.png However, keep in mind, that everything you merged will end up in the master if the merged head gets integrated.

Strip an unwanted branch

  • hg strip can be used to get rid of the unwanted branch. It is provided by the Mq Extension.
Documentation caution.png Be very careful when using it as it deletes history from your repository! Use rev hashes instead of rev numbers, as the latter are changing under strip!

Updating with multiple heads

Updating your working copy is a bit more complex when there are multiple heads in the repo. Quoth hg up --help:

   Update the repository's working directory to the specified
   revision, or the tip of the current branch if none is specified.
   Use null as the revision to remove the working copy (like 'hg
   clone -U').

So, if you clone a repo up to DEV300_m62 creating a working copy of its tip, and then pull a DEV300_m60-based cws and do a hg up you will not be on the tip of the cws, because Mercurial will not switch branches. If you want that, you would need a hg up -C -r tip.

Documentation caution.png Be careful, as this destroys any uncommited changes on the working copy. See hg up --help for details.

Containing multiple heads locally

If you (for whatever reason) have multiple heads in a local repo, pushing to outgoing will fail because it would create new heads. In this case you can specify one head and push only that one and if no new heads will be created this way, everything will work fine. Use hg heads to find the head you want to push and then use

hg push -r <changeset_id_of _selected_head>

to push this head.

Documentation caution.png You should never create multiple heads on an outgoing repo unless you really know what you are doing, because you will need to merge the heads anyway if you want your cws to be integrated someday, and thus you can do the merge before pushing just as well.

Using interwiki links to hg-wiki

You can use interwiki links to Mercurial wiki e.g. hg:OtherTools. This is may be helpful for documentation links direct to hg-wiki. Try it!

Recommended extensions

schemes extension

The schemes extension is handy to be used when developing for OOo. Sample config:

ooo =
ooos = ssh://

This allows you to:

hg pull ooo://cws/$CWSNAME


hg push ooos://cws/$CWSNAME

diffw extension

When whitespace changes are not interesting the diffw extension is very useful (until HG's issue 127 gets resolved for good).
Sample config:

 cmd.diffw = diff
 opts.diffw = -w -r -N -p -U3

This allows you to

hg diffw -r1234 -r1235
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