comparison hgext/convert/__init__.py @ 30813:2cbbd4622ab0

convert: config option to control Git committer actions

When converting a Git repository to Mercurial at Mozilla, I encountered
a scenario where I didn't want `hg convert` to automatically add the
"committer: <committer>" line to commit messages. While I can hack around
this by rewriting the Git commit before it is fed into `hg convert`,
I figured it would be a useful knob to control.

This patch introduces a config option that allows lots of control
over the committer value. I initially implemented this as a single
boolean flag to control whether to save the committer message. But
then there was feedback that it would be useful to save the committer
in extra data. While this patch doesn't implement support for saving
in extra data, it does add a mechanism for extending which actions
to take on the committer field. We should be able to easily add
actions to save in extra data.

Some of the implemented features weren't asked for. But I figured they
could be useful. If nothing else they demonstrate the extensibility
of this mechanism.

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        and copy detection more accurate but will significantly slow down
        computation on large projects. The option is only relevant if
        ``convert.git.similarity`` is greater than 0. The default is
        ``400``.

    :convert.git.extrakeys: list of extra keys from commit metadata to copy to
        the destination. Some Git repositories store extra metadata in commits.
        By default, this non-default metadata will be lost during conversion.
        Setting this config option can retain that metadata. Some built-in
        keys such as ``parent`` and ``branch`` are not allowed to be copied.

30813:2cbbd4622ab0

        and copy detection more accurate but will significantly slow down
        computation on large projects. The option is only relevant if
        ``convert.git.similarity`` is greater than 0. The default is
        ``400``.

    :convert.git.committeractions: list of actions to take when processing
        author and committer values.

        Git commits have separate author (who wrote the commit) and committer
        (who applied the commit) fields. Not all destinations support separate
        author and committer fields (including Mercurial). This config option
        controls what to do with these author and committer fields during
        conversion.

        A value of ``messagedifferent`` will append a ``committer: ...``
        line to the commit message if the Git committer is different from the
        author. The prefix of that line can be specified using the syntax
        ``messagedifferent=<prefix>``. e.g. ``messagedifferent=git-committer:``.
        When a prefix is specified, a space will always be inserted between the
        prefix and the value.

        ``messagealways`` behaves like ``messagedifferent`` except it will
        always result in a ``committer: ...`` line being appended to the commit
        message. This value is mutually exclusive with ``messagedifferent``.

        ``dropcommitter`` will remove references to the committer. Only
        references to the author will remain. Actions that add references
        to the committer will have no effect when this is set.

        ``replaceauthor`` will replace the value of the author field with
        the committer. Other actions that add references to the committer
        will still take effect when this is set.

        ``replacecommitter`` will replace the value of the committer field
        with the author.

        The default is ``messagedifferent``.

    :convert.git.extrakeys: list of extra keys from commit metadata to copy to
        the destination. Some Git repositories store extra metadata in commits.
        By default, this non-default metadata will be lost during conversion.
        Setting this config option can retain that metadata. Some built-in
        keys such as ``parent`` and ``branch`` are not allowed to be copied.