Git: diff branch against master

Compare feature branch changes with upstream:

git diff $( git merge-base master HEAD )

Thanks Bill!

Show the full patch for a git merge commit

Use the undocumented -m and -p options to show the main commit ID.
Why are these not in the help!?

git show -m -p 25172c1

Advanced subversion usage

Rebase branch on trunk

cd /working/dir/path/to/branch

svn log --stop-on-copy | tail -4 | grep ^r | cut -d' ' -f1 | sed 's/r//'
1111

svn propget db:::dweb::trunk:last_merge_from /working/dir/path/to/branch
2222

svn merge -r 1110:2222 https://remote/path/to/trunk /working/dir/path/to/branch

# check for conflicts and test

svn commit -m'Pull from trunk'

Diff branch against trunk

svn propget db:::dweb::trunk:last_merge_from /working/dir/path/to/branch
1111

svn diff https://remote/path/to/trunk@1111 https://remote/path/to/branch

See all commit messages in svn log

After merging a branch to trunk, subversion does not include commit logs from branches in the trunk log. With a little work it can be persuaded to display the log in a more useful way, see "svnlogg" perl script below.

When viewing this log output you may want to see the diff of one of the changes and naively type:

    svn diff -c 69271

...this may produce no output. However, if you type this intead:

    svn diff -c 69271 https://www.example.com/repo/branches/feature_xyz

...then you will see the expected output.

How to determine the branch name from the commit message is left as an exercise for the reader.


"svnlogg" perl script:

#!/usr/bin/env perl

# First, get all the commits.
# -v shows the filenames of changed files,
# -g shows commits from all merged branches.

my $LOG_TEMP = "/tmp/log.txt";

system("svn log -v -g > $LOG_TEMP");

# Then split the list into individual commits, filter out ones we don't want to see, and sort by date:

open(my $fh,"<",$LOG_TEMP) or die "cannot open file $LOG_TEMP";
local $/="------------------------------------------------------------------------"; # define the record separator
my @a = <$fh>; # populate an array with the commit messages
foreach my $aa (
    sort {
        # sort the commits by date (descending)
        my ($c) = $a =~ /\s\|\s(\d\d\d\d\-\d\d\-\d\d)\s/; # extract date field
        my ($d) = $b =~ /\s\|\s(\d\d\d\d\-\d\d\-\d\d)\s/; #
        $d cmp $c
    } @a
) {
    # exclude unwanted messages, especially the hundreds of "remove svn:mergeinfo"
    # also exclude the commit messages we use by convention in our organisation
    # to refer to branches and merges
    if ($aa !~ /(remove svn:mergeinfo|branching|final pull)/i) {
        print "$aa\n";
    }
}

Depending on your hardware it may be unusably slow, so pipe it into a file for viewing later.