Fixes #6750 Check git subcommand for --remote and expose errors

source_control/git

@@ -151,6 +151,34 @@ EXAMPLES = '''
 import re
 import tempfile
 
+def get_submodule_update_params(module, git_path, cwd):
+
+    #or: git submodule [--quiet] update [--init] [-N|--no-fetch] 
+    #[-f|--force] [--rebase] [--reference <repository>] [--merge] 
+    #[--recursive] [--] [<path>...]
+
+    params = []
+
+    # run a bad submodule command to get valid params    
+    cmd = "%s submodule update -" % (git_path)
+    rc, stdout, stderr = module.run_command(cmd, cwd=cwd)
+    lines = stderr.split('\n')
+    update_line = None
+    for line in lines:
+        if 'git submodule [--quiet] update ' in line:
+            update_line = line
+    if update_line:
+        update_line = update_line.replace('[','')
+        update_line = update_line.replace(']','')
+        update_line = update_line.replace('|',' ')
+        parts = shlex.split(update_line)
+        for part in parts:    
+            if part.startswith('--'):
+                part = part.replace('--', '')
+                params.append(part)
+
+    return params
+
 def write_ssh_wrapper():
     module_dir = get_module_path()
     fd, wrapper_path = tempfile.mkstemp(prefix=module_dir + '/')
@@ -383,15 +411,22 @@ def fetch(git_path, module, repo, dest, version, remote, bare):
 
 def submodule_update(git_path, module, dest):
     ''' init and update any submodules '''
+
+    # get the valid submodule params
+    params = get_submodule_update_params(module, git_path, dest)
+
     # skip submodule commands if .gitmodules is not present
     if not os.path.exists(os.path.join(dest, '.gitmodules')):
         return (0, '', '')
     cmd = [ git_path, 'submodule', 'sync' ]
     (rc, out, err) = module.run_command(cmd, check_rc=True, cwd=dest)
+    if 'remote' in params:
         cmd = [ git_path, 'submodule', 'update', '--init', '--recursive' ,'--remote' ]
+    else:
+        cmd = [ git_path, 'submodule', 'update', '--init', '--recursive' ]
     (rc, out, err) = module.run_command(cmd, cwd=dest)
     if rc != 0:
-        module.fail_json(msg="Failed to init/update submodules")
+        module.fail_json(msg="Failed to init/update submodules: %s" % out + err)
     return (rc, out, err)
 
 def switch_version(git_path, module, dest, remote, version):