Converting big bzr repository to git, what to expect?

It seems the fast-import/export tools are indeed clever enough to say "bah - you won't need this". It's not rocket science though, just like git branch -d knows when it's safe to delete a branch, so can git fast-import know that the incoming branch is a replica.

But probably you'd like to be really sure, and I agree. I put together a simple (if inefficient) script to find the list of unique bzr branches:

#!/bin/shpaths=$(bzr branches -R)for path1 in $paths; do    merged=    for path2 in $paths; do        test $path1 = $path2 && continue        # is path1 part of path2 ?        if bzr missing -d $path1 $path2 --mine >/dev/null; then            # is path2 part of path1 ?            if bzr missing -d $path1 $path2 --other >/dev/null; then                echo "# $path1 == $path2"            else                merged=1                break            fi        fi    done    test "$merged" || echo $path1done

Run this inside a Bazaar shared repository. It finds all branches, and then compares all branches against all other. If A is in B, then there are two possibilities: maybe B is also A, which means A == B. Otherwise A is really redundant.

The script filters out branches that are fully merged into at least one other branch. However, if there are multiple branches that are identical, it prints all of those, with additional lines starting with # to indicate that they are identical.

Your example commands with the bzr fast-export ... | git fast-import ... seem to have some unnecessary options. Following the examples at the very end of bzr fast-export -h, I recommend to use these steps instead:

1. Create a brand new Git repo:

   git init /tmp/gitrepo

2. Go inside your Bazaar shared repo:

   cd /path/to/bzr/shared/repo

3. Migrate your main branch (trunk?) to be the master:

   bzr fast-export --export-marks=marks.bzr trunk/ | \  GIT_DIR=/tmp/gitrepo/.git/ git fast-import --export-marks=marks.git

4. Migrate all branches:

   bzr branches -R | while read path; do    nick=$(basename $path)    echo migrating $nick ...    bzr fast-export --import-marks=marks.bzr -b $nick $path | \      GIT_DIR=/tmp/gitrepo/.git git fast-import --import-marks=marks.git \      &>/tmp/migration.logdone

If you notice the last step does not check for trunk which you already migrated. It doesn't matter, as it won't import it again anyway. Also note that even if branchA is fully merged into branchB, it will be created in Git if it is seen first. If branchB is seen first, then branchA won't be created in Git ("bah - you won't need this").

I could not find a way to force creating identical branches when importing to Git. I don't think it's possible.