bump-formula-pr: add new command.

Add a new developer command (i.e. requires `HOMEBREW_DEVELOPER` set in
your environment) to bump the version of a formula and create a new pull
request with the new version.

Closes Homebrew/homebrew#49848.

Library/Homebrew/dev-cmd/bump-formula-pr.rb

@@ -0,0 +1,114 @@
+# Creates a pull request with the new version of a formula.
+#
+# Usage: brew bump [options...] <formula-name>
+#
+# Requires either `--url` and `--sha256` or `--tag` and `--revision`.
+#
+# Options:
+#   --dry-run:  Print what would be done rather than doing it.
+#   --devel:    Bump a `devel` rather than `stable` version.
+#   --url:      The new formula URL.
+#   --sha256:   The new formula SHA-256.
+#   --tag:      The new formula's `tag`
+#   --revision: The new formula's `revision`.
+
+require "formula"
+
+module Homebrew
+  def bump_formula_pr
+    formula = ARGV.formulae.first
+    odie "No formula found!" unless formula
+
+    requested_spec, formula_spec = if ARGV.include?("--devel")
+      devel_message = " (devel)"
+      [:devel, formula.devel]
+    else
+      [:stable, formula.stable]
+    end
+    odie "#{formula}: no #{requested_spec} specification found!" unless formula
+
+    hash_type, old_hash = if (checksum = formula_spec.checksum)
+      [checksum.hash_type.to_s, checksum.hexdigest]
+    end
+
+    new_url = ARGV.value("url")
+    new_hash = ARGV.value(hash_type)
+    new_tag = ARGV.value("tag")
+    new_revision = ARGV.value("revision")
+    new_url_hash = if new_url && new_hash
+      true
+    elsif new_tag && new_revision
+      false
+    elsif !hash_type
+      odie "#{formula}: no tag/revision specified!"
+    else
+      odie "#{formula}: no url/#{hash_type} specified!"
+    end
+
+    if ARGV.dry_run?
+      ohai "brew update"
+    else
+      safe_system "brew", "update"
+    end
+
+    Utils::Inreplace.inreplace(formula.path) do |s|
+      if new_url_hash
+        old_url = formula_spec.url
+        if ARGV.dry_run?
+          ohai "replace '#{old_url}' with '#{new_url}'"
+          ohai "replace '#{old_hash}' with '#{new_hash}'"
+        else
+          s.gsub!(old_url, new_url)
+          s.gsub!(old_hash, new_hash)
+        end
+      else
+        resource_specs = formula_spec.specs
+        old_tag = resource_specs[:tag]
+        old_revision = resource_specs[:revision]
+        if ARGV.dry_run?
+          ohai "replace '#{old_tag}' with '#{new_tag}'"
+          ohai "replace '#{old_revision}' with '#{new_revision}'"
+        else
+          s.gsub!(/['"]#{old_tag}['"]/, "\"#{new_tag}\"")
+          s.gsub!(old_revision, new_revision)
+        end
+      end
+    end
+
+    new_formula = Formulary.load_formula_from_path(formula.name, formula.path)
+    new_formula_version = new_formula.version
+
+    unless Formula["hub"].any_version_installed?
+      if ARGV.dry_run?
+        ohai "brew install hub"
+      else
+        safe_system "brew", "install", "hub"
+      end
+    end
+
+    formula.path.parent.cd do
+      branch = "#{formula.name}-#{new_formula_version}"
+      if ARGV.dry_run?
+        ohai "git checkout -b #{branch} origin/master"
+        ohai "git commit --no-edit --verbose --message='#{formula.name} #{new_formula_version}#{devel_message}' -- #{formula.path}"
+        ohai "hub fork --no-remote"
+        ohai "hub fork"
+        ohai "hub fork (to read $HUB_REMOTE)"
+        ohai "git push $HUB_REMOTE #{branch}:#{branch}"
+        ohai "hub pull-request --browse -m '#{formula.name} #{new_formula_version}#{devel_message}'"
+      else
+        safe_system "git", "checkout", "-b", branch, "origin/master"
+        safe_system "git", "commit", "--no-edit", "--verbose",
+          "--message=#{formula.name} #{new_formula_version}#{devel_message}",
+          "--", formula.path
+        safe_system "hub", "fork", "--no-remote"
+        quiet_system "hub", "fork"
+        remote = Utils.popen_read("hub fork 2>&1")[/fatal: remote (.+) already exists./, 1]
+        odie "cannot get remote from 'hub'!" if remote.to_s.empty?
+        safe_system "git", "push", remote, "#{branch}:#{branch}"
+        safe_system "hub", "pull-request", "--browse", "-m",
+          "#{formula.name} #{new_formula_version}#{devel_message}\n\nCreated with `brew bump-formula-pr`."
+      end
+    end
+  end
+end