diff --git a/Library/Homebrew/dev-cmd/bump-formula-pr.rb b/Library/Homebrew/dev-cmd/bump-formula-pr.rb
index 69f1450f2b..16f3d24af6 100644
--- a/Library/Homebrew/dev-cmd/bump-formula-pr.rb
+++ b/Library/Homebrew/dev-cmd/bump-formula-pr.rb
@@ -366,15 +366,12 @@ module Homebrew
             remote_url = response.fetch("clone_url")
           end
           username = response.fetch("owner").fetch("login")
-        rescue *GitHub.api_errors
+        rescue GitHub::AuthenticationFailedError => e
+          raise unless e.github_message =~ /forking is disabled/
           # If the repository is private, forking might be disabled.
           # Create branches in the repository itself instead.
           remote_url = Utils.popen_read("git remote get-url --push origin").chomp
           username = formula.tap.user
-          repo_name = "homebrew-#{formula.tap.repo}"
-          unless GitHub.repository(username, repo_name).fetch("private")
-            raise
-          end
         rescue *GitHub.api_errors => e
           formula.path.atomic_write(backup_file) unless args.dry_run?
           odie "Unable to fork: #{e.message}!"
diff --git a/Library/Homebrew/utils/github.rb b/Library/Homebrew/utils/github.rb
index e6fc4ef43a..cbfe76a218 100644
--- a/Library/Homebrew/utils/github.rb
+++ b/Library/Homebrew/utils/github.rb
@@ -15,13 +15,22 @@ module GitHub
   PR_ENV_KEY = "HOMEBREW_NEW_FORMULA_PULL_REQUEST_URL".freeze
   PR_ENV = ENV[PR_ENV_KEY]
 
-  Error = Class.new(RuntimeError)
-  HTTPNotFoundError = Class.new(Error)
+  class Error < RuntimeError
+    attr_reader :github_message
+  end
+
+  class HTTPNotFoundError < Error
+    def initialize(github_message)
+      @github_message = github_message
+      super
+    end
+  end
 
   class RateLimitExceededError < Error
-    def initialize(reset, error)
+    def initialize(reset, github_message)
+      @github_message = github_message
       super <<~EOS
-        GitHub API Error: #{error}
+        GitHub API Error: #{github_message}
         Try again in #{pretty_ratelimit_reset(reset)}, or create a personal access token:
           #{ALL_SCOPES_URL}
         and then set the token as: export HOMEBREW_GITHUB_API_TOKEN="your_new_token"
@@ -34,8 +43,9 @@ module GitHub
   end
 
   class AuthenticationFailedError < Error
-    def initialize(error)
-      message = "GitHub #{error}\n"
+    def initialize(github_message)
+      @github_message = github_message
+      message = "GitHub #{github_message}\n"
       if ENV["HOMEBREW_GITHUB_API_TOKEN"]
         message << <<~EOS
           HOMEBREW_GITHUB_API_TOKEN may be invalid or expired; check:
@@ -193,6 +203,13 @@ module GitHub
   end
 
   def raise_api_error(output, errors, http_code, headers, scopes)
+    json = begin
+      JSON.parse(output)
+    rescue
+      nil
+    end
+    message = json&.[]("message") || "curl failed! #{errors}"
+
     meta = {}
     headers.lines.each do |l|
       key, _, value = l.delete(":").partition(" ")
@@ -204,25 +221,18 @@ module GitHub
 
     if meta.fetch("x-ratelimit-remaining", 1).to_i <= 0
       reset = meta.fetch("x-ratelimit-reset").to_i
-      error = JSON.parse(output)["message"]
-      raise RateLimitExceededError.new(reset, error)
+      raise RateLimitExceededError.new(reset, message)
     end
 
     GitHub.api_credentials_error_message(meta, scopes)
 
     case http_code
     when "401", "403"
-      raise AuthenticationFailedError, output
+      raise AuthenticationFailedError, message
     when "404"
-      raise HTTPNotFoundError, output
+      raise HTTPNotFoundError, message
     else
-      error = begin
-        JSON.parse(output)["message"]
-      rescue
-        nil
-      end
-      error ||= "curl failed! #{errors}"
-      raise Error, error
+      raise Error, message
     end
   end