From c669f1d625cd9795af397bc5a9fb78a77f45ac18 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Sun, 19 Mar 2023 23:44:44 +0800
Subject: [PATCH 1/2] pr-pull: add `--no-cherry-pick` flag

Needed for Homebrew/homebrew-core#125556. Without this, `pr-pull`
attempts to cherry-pick commits from the PR branch onto the PR branch,
and then gets upset that nothing happened.

See https://github.com/Homebrew/homebrew-core/actions/runs/4461335852/jobs/7835095294#step:10:40
---
 Library/Homebrew/dev-cmd/pr-pull.rb | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/dev-cmd/pr-pull.rb b/Library/Homebrew/dev-cmd/pr-pull.rb
index 9a1a1618b9..378ae6e2ff 100644
--- a/Library/Homebrew/dev-cmd/pr-pull.rb
+++ b/Library/Homebrew/dev-cmd/pr-pull.rb
@@ -22,6 +22,8 @@ module Homebrew
              description: "Download the bottles but don't upload them."
       switch "--no-commit",
              description: "Do not generate a new commit before uploading."
+      switch "--no-cherry-pick",
+             description: "Do not cherry-pick commits from the pull request branch."
       switch "-n", "--dry-run",
              description: "Print what would be done rather than doing it."
       switch "--clean",
@@ -450,7 +452,7 @@ module Homebrew
           original_commit = ENV["GITHUB_SHA"].presence || tap.path.git_head
 
           unless args.no_commit?
-            cherry_pick_pr!(user, repo, pr, path: tap.path, args: args)
+            cherry_pick_pr!(user, repo, pr, path: tap.path, args: args) unless args.no_cherry_pick?
             if !args.no_autosquash? && !args.dry_run?
               autosquash!(original_commit, tap: tap,
                           verbose: args.verbose?, resolve: args.resolve?, reason: args.message)
@@ -458,7 +460,13 @@ module Homebrew
             signoff!(tap.path, pr: pr, dry_run: args.dry_run?) unless args.clean?
           end
 
-          unless formulae_need_bottles?(tap, original_commit, user, repo, pr, args: args)
+          # TODO: Fix determination of `original_commit` above for the `--no-cherry-pick` flag.
+          #       When we pull to the PR branch that contains the commits we want to merge,
+          #       `#formulae_need_bottles?` mistakenly returns `true`, because it thinks
+          #       that no formulae have changed. We probably want to use the commit identified
+          #       by `git merge-base`.
+          if !formulae_need_bottles?(tap, original_commit, user, repo, pr, args: args) &&
+             !args.no_cherry_pick?
             ohai "Skipping artifacts for ##{pr} as the formulae don't need bottles"
             next
           end

From e5b9e97b920f37429142756d95e8a009599ec58a Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Mon, 20 Mar 2023 00:55:20 +0800
Subject: [PATCH 2/2] Use `git merge-base` to determine `original_commit`

---
 Library/Homebrew/dev-cmd/pr-pull.rb | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/Library/Homebrew/dev-cmd/pr-pull.rb b/Library/Homebrew/dev-cmd/pr-pull.rb
index 378ae6e2ff..e8ec2195db 100644
--- a/Library/Homebrew/dev-cmd/pr-pull.rb
+++ b/Library/Homebrew/dev-cmd/pr-pull.rb
@@ -449,7 +449,13 @@ module Homebrew
       ohai "Fetching #{tap} pull request ##{pr}"
       Dir.mktmpdir pr do |dir|
         cd dir do
-          original_commit = ENV["GITHUB_SHA"].presence || tap.path.git_head
+          current_branch_head = ENV["GITHUB_SHA"] || tap.git_head
+          original_commit = if args.no_cherry_pick?
+            # TODO: Handle the case where `merge-base` returns multiple commits.
+            Utils.safe_popen_read("git", "-C", tap.path, "merge-base", "origin/HEAD", current_branch_head).strip
+          else
+            current_branch_head
+          end
 
           unless args.no_commit?
             cherry_pick_pr!(user, repo, pr, path: tap.path, args: args) unless args.no_cherry_pick?
@@ -460,13 +466,7 @@ module Homebrew
             signoff!(tap.path, pr: pr, dry_run: args.dry_run?) unless args.clean?
           end
 
-          # TODO: Fix determination of `original_commit` above for the `--no-cherry-pick` flag.
-          #       When we pull to the PR branch that contains the commits we want to merge,
-          #       `#formulae_need_bottles?` mistakenly returns `true`, because it thinks
-          #       that no formulae have changed. We probably want to use the commit identified
-          #       by `git merge-base`.
-          if !formulae_need_bottles?(tap, original_commit, user, repo, pr, args: args) &&
-             !args.no_cherry_pick?
+          unless formulae_need_bottles?(tap, original_commit, user, repo, pr, args: args)
             ohai "Skipping artifacts for ##{pr} as the formulae don't need bottles"
             next
           end