From 8f3605e7d620192357b1ef4a0a57b92a3449d887 Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Mon, 17 May 2021 16:40:35 -0400 Subject: Add script for identifying commits in release branches One of the worst parts of a Podman release is writing the release notes. It requires manually going through all merged commits since the last release, figuring out what was actually done, and writing a small blurb about what was fixed. The worst part of this is the difficulty in finding the commits that were actually included in previous releases - our extensive backports to prior releases mean that there are usually dozens of commits that were included in a prior release, but do not have a matching SHA (as the original author did not do the backport, and often the commit required massaging to cherry-pick in). This script automates the job of finding commits in one release branch that are not in another, with filtering to remove most cherry-picked commits. It makes my life a lot easier during releases, so I figured I'd include it in hack/ so anyone else stuck with the enjoyable task of writing release notes can have a slightly easier life. The script is written in absolutely terrible Ruby and its performance is absolutely terrible, but you only need to run it once per major release and a 30-second wait to generate the list of commits to include isn't bad. Signed-off-by: Matthew Heon --- hack/branch_commits.rb | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100755 hack/branch_commits.rb (limited to 'hack/branch_commits.rb') diff --git a/hack/branch_commits.rb b/hack/branch_commits.rb new file mode 100755 index 000000000..f13f8b2d0 --- /dev/null +++ b/hack/branch_commits.rb @@ -0,0 +1,98 @@ +#!/usr/bin/ruby + +require 'set' + +# Get commits in one branch, but not in another, accounting for cherry-picks. +# Accepts two arguments: base branch and old branch. Commits in base branch that +# are not in old branch will be reported. + +# Preface: I know exactly enough ruby to be dangerous with it. +# For anyone reading this who is actually skilled at writing Ruby, I can only +# say I'm very, very sorry. + +# Utility functions: + +# Check if a given Git branch exists +def CheckBranchExists(branch) + return `git branch --list #{branch}`.rstrip.empty? +end + +# Returns author (email) and commit subject for the given hash +def GetCommitInfo(hash) + info = `git log -n 1 --format='%ae%n%s' #{hash}`.split("\n") + if info.length != 2 + puts("Badly-formatted commit with hash #{hash}") + exit(127) + end + return info[0], info[1] +end + +# Actual script begins here + +if ARGV.length != 2 + puts("Must provide exactly 2 arguments, base branch and old branch") + exit(127) +end + +# Both branches must exist +ARGV.each do |branch| + if !CheckBranchExists(branch) + puts("Branch #{branch} does not exist") + exit(127) + end +end + +base = ARGV[0] +old = ARGV[1] + +# Get a base list of commits +commits = `git log --no-merges --format=%H #{base} ^#{old}`.split("\n") + +# Alright, now for the hacky bit. +# We want to remove every commit with a shortlog precisely matching something in +# the old branch. This is an effort to catch cherry-picks, where commit ID has +# almost certainly changed because the committer is different (and possibly +# conflicts needed to be resolved). +# We will match also try and match author, but not committer (which is reset to +# whoever did the cherry-pick). We will *not* match full commit body - I +# routinely edit these when I fix cherry-pick conflicts to indicate that I made +# changes. A more ambitious future committer could attempt to see if the body of +# the commit message in the old branch is a subset of the full commit message +# from the base branch, but there are potential performance implications in that +# due to the size of the string comparison that would be needed. +# This will not catch commits where the shortlog is deliberately altered as part +# of the cherry pick... But we can just ask folks not to do that, I guess? +# (A classic example of something this wouldn't catch: cherry-picking a commit +# to a branch and then prepending the branch name to the commit subject. I see +# this a lot in Github PR subjects, but fortunately not much at all in actual +# commit subjects). + +# Begin by fetching commit author + subject for each commit in old branch. +# Map each author to an array of potential commit subjects. +oldIndex = {} + +# TODO: This could probably be made a whole lot more efficient by unifying the +# GetCommitInfo bits into two big `git log --format` calls. +# But I'm not really ambitious enough to do that... +oldCommits = `git log --no-merges --format=%H #{old}`.split("\n") +oldCommits.each do |hash| + name, subject = GetCommitInfo(hash) + if oldIndex[name] == nil + oldIndex[name] = Set[] + end + oldIndex[name].add(subject) +end + +# Go through our earlier commits list and check for matches. +filtered = commits.reject do |hash| + name, subject = GetCommitInfo(hash) + oldIndex[name] != nil && oldIndex[name].include?(subject) +end + +# We have now filtered out all commits we want to filter. +# Now we just have to print all remaining commits. +# This breaks the default pager, but we can just pipe to less. +filtered.each do |hash| + puts `git log -n 1 #{hash}` + puts "\n" +end -- cgit v1.2.3-54-g00ecf