From 4fe882e2c925c067693fbd432228d92548481ec4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Rodr=C3=ADguez?= <deivid.rodriguez@riseup.net>
Date: Mon, 17 Mar 2025 20:10:17 +0100
Subject: [PATCH] [rubygems/rubygems] Let `gem exec` raise an error in
 ambiguous cases

When `gem exec foo` is run, and "foo" is a gem that has multiple
executables, none of them named "foo", raise an error explaining the
situation and telling user to be more specific.

Currently the first command in the executables array is run, but this
may come as surprising sometimes, so better raise an error.

https://github.com/rubygems/rubygems/commit/acda5d8f6e
---
 lib/rubygems/commands/exec_command.rb         | 21 +++++++++++++------
 .../test_gem_commands_exec_command.rb         |  7 +++++--
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/lib/rubygems/commands/exec_command.rb b/lib/rubygems/commands/exec_command.rb
index 519539c694..82f1734b58 100644
--- a/lib/rubygems/commands/exec_command.rb
+++ b/lib/rubygems/commands/exec_command.rb
@@ -195,7 +195,7 @@ to the same gem path as user-installed gems.
     argv = ARGV.clone
     ARGV.replace options[:args]
 
-    exe = executable = options[:executable]
+    executable = options[:executable]
 
     contains_executable = Gem.loaded_specs.values.select do |spec|
       spec.executables.include?(executable)
@@ -206,13 +206,22 @@ to the same gem path as user-installed gems.
     end
 
     if contains_executable.empty?
-      if (spec = Gem.loaded_specs[executable]) && (exe = spec.executable)
-        contains_executable << spec
-      else
+      spec = Gem.loaded_specs[executable]
+
+      if spec.nil? || spec.executables.empty?
         alert_error "Failed to load executable `#{executable}`," \
               " are you sure the gem `#{options[:gem_name]}` contains it?"
         terminate_interaction 1
       end
+
+      if spec.executables.size > 1
+        alert_error "Ambiguous which executable from gem `#{executable}` should be run: " \
+              "the options are #{spec.executables}, specify one via COMMAND, and use `-g` and `-v` to specify gem and version"
+        terminate_interaction 1
+      end
+
+      contains_executable << spec
+      executable = spec.executable
     end
 
     if contains_executable.size > 1
@@ -223,8 +232,8 @@ to the same gem path as user-installed gems.
     end
 
     old_exe = $0
-    $0 = exe
-    load Gem.activate_bin_path(contains_executable.first.name, exe, ">= 0.a")
+    $0 = executable
+    load Gem.activate_bin_path(contains_executable.first.name, executable, ">= 0.a")
   ensure
     $0 = old_exe if old_exe
     ARGV.replace argv
diff --git a/test/rubygems/test_gem_commands_exec_command.rb b/test/rubygems/test_gem_commands_exec_command.rb
index b9d5888068..806a6b5424 100644
--- a/test/rubygems/test_gem_commands_exec_command.rb
+++ b/test/rubygems/test_gem_commands_exec_command.rb
@@ -370,8 +370,11 @@ class TestGemCommandsExecCommand < Gem::TestCase
     util_clear_gems
 
     use_ui @ui do
-      @cmd.invoke "a:2"
-      assert_equal "a-2 foo\n", @ui.output
+      e = assert_raise Gem::MockGemUi::TermError do
+        @cmd.invoke "a:2"
+      end
+      assert_equal 1, e.exit_code
+      assert_equal "ERROR:  Ambiguous which executable from gem `a` should be run: the options are [\"foo\", \"bar\"], specify one via COMMAND, and use `-g` and `-v` to specify gem and version\n", @ui.error
     end
   end