We're not rejecting multi commands below chained multi commands. This fixes #415

3 files changed, 27 insertions, 1 deletions

diff --git a/CHANGES b/CHANGES
index e49a437..51fffc1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -10,6 +10,9 @@ Version 6.0
 
 - Optimized the progressbar rendering to not render when it did not
   actually change.
+- Actively reject multi commands within chained multi commands.  This
+  cannot be supported with the current setup of how the invocation for
+  subcommands works.
 
 Version 5.1
 -----------
diff --git a/click/core.py b/click/core.py
index b3b51c4..e4aaca9 100644
--- a/click/core.py
+++ b/click/core.py
@@ -37,6 +37,25 @@ def _bashcomplete(cmd, prog_name, complete_var=None):
         sys.exit(1)
 
 
+def _check_multicommand(base_command, cmd_name, cmd, register=False):
+    if not base_command.chain or not isinstance(cmd, MultiCommand):
+        return
+    if register:
+        hint = 'It is not possible to add multi commands as children to ' \
+               'another multi command that is in chain mode'
+    else:
+        hint = 'Found a multi command as subcommand to a multi command ' \
+               'that is in chain mode.  This is not supported'
+    raise RuntimeError('%s.  Command "%s" is set to chain and "%s" was '
+                       'added as subcommand but it in itself is a '
+                       'multi command.  ("%s" is a %s within a chained '
+                       '%s named "%s")' % (
+                           hint, base_command.name, cmd_name,
+                           cmd_name, cmd.__class__.__name__,
+                           base_command.__class__.__name__,
+                           base_command.name))
+
+
 def batch(iterable, batch_size):
     return list(zip(*repeat(iter(iterable), batch_size)))
 
@@ -1111,6 +1130,7 @@ class Group(MultiCommand):
         name = name or cmd.name
         if name is None:
             raise TypeError('Command has no name.')
+        _check_multicommand(self, name, cmd, register=True)
         self.commands[name] = cmd
 
     def command(self, *args, **kwargs):
@@ -1163,6 +1183,8 @@ class CommandCollection(MultiCommand):
     def get_command(self, ctx, cmd_name):
         for source in self.sources:
             rv = source.get_command(ctx, cmd_name)
+            if self.chain:
+                _check_multicommand(self, cmd_name, rv)
             if rv is not None:
                 return rv
 
diff --git a/docs/commands.rst b/docs/commands.rst
index 642f873..157d004 100644
--- a/docs/commands.rst
+++ b/docs/commands.rst
@@ -310,7 +310,8 @@ Now you can invoke it like this:
     invoke(cli, prog_name='setup.py', args=['sdist', 'bdist_wheel'])
 
 When using multi command chaining you can only have one command (the last)
-use ``nargs=-1`` on an argument.  Other than that there are no
+use ``nargs=-1`` on an argument.  It is also not possible to nest multi
+commands below chained multicommands.  Other than that there are no
 restrictions on how they work.  They can accept options and arguments as
 normal.