comparison tests/test-convert.t @ 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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                    files in a commit. Increasing this will make rename 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

30813:2cbbd4622ab0

                    files in a commit. Increasing this will make rename 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