Merge branch '3.x'

1 files changed, 10 insertions, 4 deletions

diff --git a/sphinx/domains/std.py b/sphinx/domains/std.py
index eac5977e5..67eb3a26f 100644
--- a/sphinx/domains/std.py
+++ b/sphinx/domains/std.py
@@ -41,7 +41,7 @@ logger = logging.getLogger(__name__)
 
 
 # RE for option descriptions
-option_desc_re = re.compile(r'((?:/|--|-|\+)?[^\s=[]+)(=?\s*.*)')
+option_desc_re = re.compile(r'((?:/|--|-|\+)?[^\s=]+)(=?\s*.*)')
 # RE for grammar tokens
 token_re = re.compile(r'`(\w+)`', re.U)
 
@@ -195,6 +195,11 @@ class Cmdoption(ObjectDescription):
                                location=signode)
                 continue
             optname, args = m.groups()
+            if optname.endswith('[') and args.endswith(']'):
+                # optional value surrounded by brackets (ex. foo[=bar])
+                optname = optname[:-1]
+                args = '[' + args
+
             if count:
                 signode += addnodes.desc_addname(', ', ', ')
             signode += addnodes.desc_name(optname, optname)
@@ -832,8 +837,9 @@ class StandardDomain(Domain):
             if fignumber is None:
                 return contnode
         except ValueError:
-            logger.warning(__("no number is assigned for %s: %s"), figtype, labelid,
-                           location=node)
+            logger.warning(__("Failed to create a cross reference. Any number is not "
+                              "assigned: %s"),
+                           labelid, location=node)
             return contnode
 
         try:
@@ -1074,7 +1080,7 @@ class StandardDomain(Domain):
 
 
 def warn_missing_reference(app: "Sphinx", domain: Domain, node: pending_xref) -> bool:
-    if domain.name != 'std' or node['reftype'] != 'ref':
+    if (domain and domain.name != 'std') or node['reftype'] != 'ref':
         return None
     else:
         target = node['reftarget']