Fix merging with missing environments. (apache#30864)

sdks/python/apache_beam/runners/common.py

@@ -1981,27 +1981,34 @@ def env_key(env):
             base_env_key(e)
             for e in environments.expand_anyof_environments(env)))
 
-  cannonical_enviornments = collections.defaultdict(list)
+  canonical_environments = collections.defaultdict(list)
   for env_id, env in pipeline_proto.components.environments.items():
-    cannonical_enviornments[env_key(env)].append(env_id)
+    canonical_environments[env_key(env)].append(env_id)
 
-  if len(cannonical_enviornments) == len(
-      pipeline_proto.components.environments):
+  if len(canonical_environments) == len(pipeline_proto.components.environments):
     # All environments are already sufficiently distinct.
     return pipeline_proto
 
   environment_remappings = {
       e: es[0]
-      for es in cannonical_enviornments.values() for e in es
+      for es in canonical_environments.values() for e in es
   }
 
   if not inplace:
     pipeline_proto = copy.copy(pipeline_proto)
 
   for t in pipeline_proto.components.transforms.values():
+    if t.environment_id not in pipeline_proto.components.environments:
+      # TODO(https://github.com/apache/beam/issues/30876): Remove this
+      #  workaround.
+      continue
     if t.environment_id:
       t.environment_id = environment_remappings[t.environment_id]
   for w in pipeline_proto.components.windowing_strategies.values():
+    if w.environment_id not in pipeline_proto.components.environments:
+      # TODO(https://github.com/apache/beam/issues/30876): Remove this
+      #  workaround.
+      continue
     if w.environment_id:
       w.environment_id = environment_remappings[w.environment_id]
   for e in set(pipeline_proto.components.environments.keys()) - set(