From 4bdc11ddc97ccf2c7b822e7485bab65f940a69e9 Mon Sep 17 00:00:00 2001
From: Rylan Polster <rslpolster@gmail.com>
Date: Mon, 25 Jan 2021 23:57:01 -0500
Subject: [PATCH] tap: fix renamed branches with `brew tap --repair`

---
 Library/Homebrew/cmd/tap.rb               |  1 +
 Library/Homebrew/extend/git_repository.rb | 23 +++++++++++++++++++++++
 Library/Homebrew/tap.rb                   | 16 ++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/Library/Homebrew/cmd/tap.rb b/Library/Homebrew/cmd/tap.rb
index 2868cabbcb..d352143c7a 100644
--- a/Library/Homebrew/cmd/tap.rb
+++ b/Library/Homebrew/cmd/tap.rb
@@ -50,6 +50,7 @@ module Homebrew
 
     if args.repair?
       Tap.each(&:link_completions_and_manpages)
+      Tap.each(&:fix_remote_configuration)
     elsif args.list_pinned?
       puts Tap.select(&:pinned?).map(&:name)
     elsif args.no_named?
diff --git a/Library/Homebrew/extend/git_repository.rb b/Library/Homebrew/extend/git_repository.rb
index e490e12eee..b5a54742f8 100644
--- a/Library/Homebrew/extend/git_repository.rb
+++ b/Library/Homebrew/extend/git_repository.rb
@@ -54,6 +54,18 @@ module GitRepositoryExtension
     popen_git("rev-parse", "--abbrev-ref", "HEAD", safe: safe)
   end
 
+  # Change the name of a local branch
+  sig { params(old: String, new: String).void }
+  def git_rename_branch(old:, new:)
+    popen_git("branch", "-m", old, new)
+  end
+
+  # Set an upstream branch for a local branch to track
+  sig { params(local: String, origin: String).void }
+  def git_branch_set_upstream(local:, origin:)
+    popen_git("branch", "-u", "origin/#{origin}", local)
+  end
+
   # Gets the name of the default origin HEAD branch.
   sig { returns(T.nilable(String)) }
   def git_origin_branch
@@ -72,6 +84,17 @@ module GitRepositoryExtension
     popen_git("show", "-s", "--format=%cd", "--date=short", "HEAD")
   end
 
+  # Returns true if the given branch exists on origin
+  sig { params(branch: String).returns(T::Boolean) }
+  def git_origin_has_branch?(branch)
+    popen_git("ls-remote", "--heads", "origin", branch).present?
+  end
+
+  sig { void }
+  def git_origin_set_head_auto
+    popen_git("remote", "set-head", "origin", "--auto")
+  end
+
   # Gets the full commit message of the specified commit, or of the HEAD commit if unspecified.
   sig { params(commit: String, safe: T::Boolean).returns(T.nilable(String)) }
   def git_commit_message(commit = "HEAD", safe: false)
diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index 986e35dc13..9a49c29424 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -362,6 +362,22 @@ class Tap
     end
   end
 
+  def fix_remote_configuration
+    return unless remote.include? "github.com"
+
+    current_upstream_head = path.git_origin_branch
+    return if path.git_origin_has_branch? current_upstream_head
+
+    safe_system "git", "-C", path, "fetch", "origin"
+    path.git_origin_set_head_auto
+
+    new_upstream_head = path.git_origin_branch
+    path.git_rename_branch old: current_upstream_head, new: new_upstream_head
+    path.git_branch_set_upstream local: new_upstream_head, origin: new_upstream_head
+
+    ohai "#{name}: changed default branch name from #{current_upstream_head} to #{new_upstream_head}"
+  end
+
   # Uninstall this {Tap}.
   def uninstall(manual: false)
     require "descriptions"