Print bin/rails help on unrecognized bare options

Prior to this commit, `bin/rails` would pass unrecognized bare options
on to Rake:

  ```console
  $ bin/rails -v
  Rails 7.2.0.alpha

  $ bin/rails -V
  rake, version 13.0.6

  $ bin/rails -s
  Running 0 tests in a single process (parallelization threshold is 50)
  ...

  $ bin/rails -S
  invalid option: -S

  $ bin/rails -T
  # Prints list of Rake tasks...
  ```

This commit changes `bin/rails` to print its help message when given an
unrecognized bare option:

  ```console
  $ bin/rails -v
  Rails 7.2.0.alpha

  $ bin/rails -V
  Usage:
    bin/rails COMMAND [options]

  You must specify a command. The most common commands are:
  ...

  $ bin/rails -s
  Usage:
    bin/rails COMMAND [options]

  You must specify a command. The most common commands are:
  ...

  $ bin/rails -S
  Usage:
    bin/rails COMMAND [options]

  You must specify a command. The most common commands are:
  ...

  $ bin/rails -T
  Usage:
    bin/rails COMMAND [options]

  You must specify a command. The most common commands are:
  ...
  ```

Addresses rails#50712.
Closes rails#50700.

guides/source/active_record_multiple_databases.md

@@ -160,39 +160,41 @@ multiply the number of connections you have since Rails uses the model class nam
 connection specification name.
 
 Now that we have the `database.yml` and the new model set up, it's time to create the databases.
-Rails 6.0 ships with all the rails tasks you need to use multiple databases in Rails.
+Rails ships with all the commands you need to use multiple databases.
 
-You can run `bin/rails -T` to see all the commands you're able to run. You should see the following:
+You can run `bin/rails --help` to see all the commands you're able to run. You should see the following:
 
 ```bash
-$ bin/rails -T
-bin/rails db:create                          # Create the database from DATABASE_URL or config/database.yml for the ...
-bin/rails db:create:animals                  # Create animals database for current environment
-bin/rails db:create:primary                  # Create primary database for current environment
-bin/rails db:drop                            # Drop the database from DATABASE_URL or config/database.yml for the cu...
-bin/rails db:drop:animals                    # Drop animals database for current environment
-bin/rails db:drop:primary                    # Drop primary database for current environment
-bin/rails db:migrate                         # Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)
-bin/rails db:migrate:animals                 # Migrate animals database for current environment
-bin/rails db:migrate:primary                 # Migrate primary database for current environment
-bin/rails db:migrate:status                  # Display status of migrations
-bin/rails db:migrate:status:animals          # Display status of migrations for animals database
-bin/rails db:migrate:status:primary          # Display status of migrations for primary database
-bin/rails db:reset                           # Drop and recreates all databases from their schema for the current environment and loads the seeds
-bin/rails db:reset:animals                   # Drop and recreates the animals database from its schema for the current environment and loads the seeds
-bin/rails db:reset:primary                   # Drop and recreates the primary database from its schema for the current environment and loads the seeds
-bin/rails db:rollback                        # Roll the schema back to the previous version (specify steps w/ STEP=n)
-bin/rails db:rollback:animals                # Rollback animals database for current environment (specify steps w/ STEP=n)
-bin/rails db:rollback:primary                # Rollback primary database for current environment (specify steps w/ STEP=n)
-bin/rails db:schema:dump                     # Create a database schema file (either db/schema.rb or db/structure.sql  ...
-bin/rails db:schema:dump:animals             # Create a database schema file (either db/schema.rb or db/structure.sql  ...
-bin/rails db:schema:dump:primary             # Create a db/schema.rb file that is portable against any DB supported  ...
-bin/rails db:schema:load                     # Load a database schema file (either db/schema.rb or db/structure.sql  ...
-bin/rails db:schema:load:animals             # Load a database schema file (either db/schema.rb or db/structure.sql  ...
-bin/rails db:schema:load:primary             # Load a database schema file (either db/schema.rb or db/structure.sql  ...
-bin/rails db:setup                           # Create all databases, loads all schemas, and initializes with the seed data (use db:reset to also drop all databases first)
-bin/rails db:setup:animals                   # Create the animals database, loads the schema, and initializes with the seed data (use db:reset:animals to also drop the database first)
-bin/rails db:setup:primary                   # Create the primary database, loads the schema, and initializes with the seed data (use db:reset:primary to also drop the database first)
+$ bin/rails --help
+...
+db:create                          # Create the database from DATABASE_URL or config/database.yml for the ...
+db:create:animals                  # Create animals database for current environment
+db:create:primary                  # Create primary database for current environment
+db:drop                            # Drop the database from DATABASE_URL or config/database.yml for the cu...
+db:drop:animals                    # Drop animals database for current environment
+db:drop:primary                    # Drop primary database for current environment
+db:migrate                         # Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)
+db:migrate:animals                 # Migrate animals database for current environment
+db:migrate:primary                 # Migrate primary database for current environment
+db:migrate:status                  # Display status of migrations
+db:migrate:status:animals          # Display status of migrations for animals database
+db:migrate:status:primary          # Display status of migrations for primary database
+db:reset                           # Drop and recreates all databases from their schema for the current environment and loads the seeds
+db:reset:animals                   # Drop and recreates the animals database from its schema for the current environment and loads the seeds
+db:reset:primary                   # Drop and recreates the primary database from its schema for the current environment and loads the seeds
+db:rollback                        # Roll the schema back to the previous version (specify steps w/ STEP=n)
+db:rollback:animals                # Rollback animals database for current environment (specify steps w/ STEP=n)
+db:rollback:primary                # Rollback primary database for current environment (specify steps w/ STEP=n)
+db:schema:dump                     # Create a database schema file (either db/schema.rb or db/structure.sql  ...
+db:schema:dump:animals             # Create a database schema file (either db/schema.rb or db/structure.sql  ...
+db:schema:dump:primary             # Create a db/schema.rb file that is portable against any DB supported  ...
+db:schema:load                     # Load a database schema file (either db/schema.rb or db/structure.sql  ...
+db:schema:load:animals             # Load a database schema file (either db/schema.rb or db/structure.sql  ...
+db:schema:load:primary             # Load a database schema file (either db/schema.rb or db/structure.sql  ...
+db:setup                           # Create all databases, loads all schemas, and initializes with the seed data (use db:reset to also drop all databases first)
+db:setup:animals                   # Create the animals database, loads the schema, and initializes with the seed data (use db:reset:animals to also drop the database first)
+db:setup:primary                   # Create the primary database, loads the schema, and initializes with the seed data (use db:reset:primary to also drop the database first)
+...
 ```
 
 Running a command like `bin/rails db:create` will create both the primary and animals databases.

railties/CHANGELOG.md

@@ -1,3 +1,65 @@
+*   `bin/rails` now prints its help message when given an unrecognized bare
+    option.
+
+    __Before__
+
+      ```console
+      $ bin/rails -v
+      Rails 7.2.0.alpha
+
+      $ bin/rails -V
+      rake, version 13.0.6
+
+      $ bin/rails -s
+      Running 0 tests in a single process (parallelization threshold is 50)
+      ...
+
+      $ bin/rails -S
+      invalid option: -S
+
+      $ bin/rails -T
+      # Prints list of Rake tasks...
+      ```
+
+    __After__
+
+      ```console
+      $ bin/rails -v
+      Rails 7.2.0.alpha
+
+      $ bin/rails -V
+      Usage:
+        bin/rails COMMAND [options]
+
+      You must specify a command. The most common commands are:
+      ...
+
+      $ bin/rails -s
+      Usage:
+        bin/rails COMMAND [options]
+
+      You must specify a command. The most common commands are:
+      ...
+
+      $ bin/rails -S
+      Usage:
+        bin/rails COMMAND [options]
+
+      You must specify a command. The most common commands are:
+      ...
+
+      $ bin/rails -T
+      Usage:
+        bin/rails COMMAND [options]
+
+      You must specify a command. The most common commands are:
+      ...
+      ```
+
+    To print the list of Rake tasks, use `bin/rake -T` / `bin/rake --tasks`.
+
+    *Jonathan Hefner*
+
 *   Ensure `autoload_paths`, `autoload_once_paths`, `eager_load_paths`, and
     `load_paths` only have directories when initialized from engine defaults.
     Previously, files under the `app` directory could end up there too.

railties/lib/rails/command.rb

@@ -130,14 +130,14 @@ def rails_new_with_no_path?(args)
 
         def split_namespace(namespace)
           case namespace
-          when /^(.+):(\w+)$/
-            [$1, $2]
-          when ""
-            ["help", "help"]
           when HELP_MAPPINGS, "help"
             ["help", "help_extended"]
           when VERSION_MAPPINGS
             ["version", "version"]
+          when /^-/, ""
+            ["help", "help"]
+          when /^(.+):(\w+)$/
+            [$1, $2]
           else
             [namespace, namespace]
           end

railties/test/command/help_integration_test.rb

@@ -7,6 +7,12 @@ class Rails::Command::HelpIntegrationTest < ActiveSupport::TestCase
   setup :build_app
   teardown :teardown_app
 
+  test "prints help on unrecognized bare option" do
+    %w[-z --zzz -T --tasks].each do |option|
+      assert_match "You must specify a command.", rails(option)
+    end
+  end
+
   test "prints helpful error on unrecognized command" do
     output = rails "vershen", allow_failure: true