use utils/submodule in setup.py

`setup.py anything` will halt with an informative error
if the submodules are unclean.

It will fetch the submodules if they are entirely absent.

Nothing will happen if it is not a git repo.

setup.py

@@ -68,7 +68,7 b' from setupbase import ('
     find_data_files,
     check_for_dependencies,
     git_prebuild,
-    check_for_submodules,
+    check_submodule_status,
     update_submodules,
     require_submodules,
     UpdateSubmodules,
@@ -112,21 +112,37 b" if os_name == 'windows' and 'sdist' in sys.argv:"
 #-------------------------------------------------------------------------------
 # Make sure we aren't trying to run without submodules
 #-------------------------------------------------------------------------------
+here = os.path.abspath(os.path.dirname(__file__))
 
-def ensure_submodules_exist():
-    """Check out git submodules before distutils can do anything
-    
-    Because distutils cannot be trusted to update the tree
-    after everything has been set in motion.
+def require_clean_submodules():
+    """Check on git submodules before distutils can do anything
+
+    Since distutils cannot be trusted to update the tree
+    after everything has been set in motion,
+    this is not a distutils command.
     """
     # don't do anything if nothing is actually supposed to happen
-    for do_nothing in ('-h', '--help', '--help-commands', 'clean'):
+    for do_nothing in ('-h', '--help', '--help-commands', 'clean', 'submodule'):
         if do_nothing in sys.argv:
             return
-    if not check_for_submodules():
-        update_submodules()
 
-ensure_submodules_exist()
+    status = check_submodule_status(here)
+
+    if status == "missing":
+        print("checking out submodules for the first time")
+        update_submodules(here)
+    elif status == "unclean":
+        print('\n'.join([
+            "Cannot build / install IPython with unclean submodules",
+            "Please update submodules with",
+            "    python setup.py submodule",
+            "or",
+            "    git submodule update",
+            "or commit any submodule changes you have made."
+        ]))
+        sys.exit(1)
+
+require_clean_submodules()
 
 #-------------------------------------------------------------------------------
 # Things related to the IPython documentation

setupbase.py

@@ -373,27 +373,10 b' def check_for_dependencies():'
 # VCS related
 #---------------------------------------------------------------------------
 
-def check_for_submodules():
-    """return False if there are any submodules that need to be checked out,
-    True otherwise.
-    
-    This doesn't check if they are up to date, only existence.
-    """
-    here = os.path.dirname(__file__)
-    submodules = [
-        os.path.join(here, 'IPython', 'frontend', 'html', 'notebook', 'static', 'components')
-    ]
-    for submodule in submodules:
-        if not os.path.exists(submodule):
-            return False
-    return True
+here = os.path.abspath(os.path.dirname(__file__))
 
-def update_submodules():
-    """update git submodules"""
-    import subprocess
-    print("updating git submodules")
-    subprocess.check_call('git submodule init'.split())
-    subprocess.check_call('git submodule update --recursive'.split())
+# utils.submodule has checks for submodule status
+execfile(pjoin('IPython','utils','submodule.py'), globals())
 
 class UpdateSubmodules(Command):
     """Update git submodules
@@ -418,12 +401,10 b' class UpdateSubmodules(Command):'
             failure = e
             print(e)
         
-        if not check_for_submodules():
+        if not check_submodule_status(here) == 'clean':
             print("submodules could not be checked out")
             sys.exit(1)
-        
-        # re-scan package data after update
-        self.distribution.package_data = find_package_data()
+
 
 def git_prebuild(pkg_dir, build_cmd=build_py):
     """Return extended build or sdist command class for recording commit
@@ -438,10 +419,6 b' def git_prebuild(pkg_dir, build_cmd=build_py):'
     class MyBuildPy(build_cmd):
         ''' Subclass to write commit data into installation tree '''
         def run(self):
-            if not check_for_submodules():
-                print("submodules missing! Run `setup.py submodule` and try again")
-                sys.exit(1)
-            
             build_cmd.run(self)
             # this one will only fire for build commands
             if hasattr(self, 'build_lib'):
@@ -478,14 +455,14 b' def git_prebuild(pkg_dir, build_cmd=build_py):'
                     '# GENERATED BY setup.py\n',
                     'commit = "%s"\n' % repo_commit,
                 ])
-    return MyBuildPy
+    return require_submodules(MyBuildPy)
 
 
 def require_submodules(command):
     """decorator for instructing a command to check for submodules before running"""
     class DecoratedCommand(command):
         def run(self):
-            if not check_for_submodules():
+            if not check_submodule_status(here) == 'clean':
                 print("submodules missing! Run `setup.py submodule` and try again")
                 sys.exit(1)
             command.run(self)