Remove null fields form LSP response (microsoft#15329)

* Remove null fields form LSP response

* Addressing comments

* Add unicode for 2.7 and address comments

* Cleanup comments

* Simplify how we check for unicode availability

* Address comments and add support for dicts

* Using filter instead of list comprehension

Author: karthiknadig

pythonFiles/runJediLanguageServer.py

@@ -5,6 +5,87 @@
 EXTENSION_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.append(os.path.join(EXTENSION_ROOT, "pythonFiles", "lib", "python"))
 
+import pygls.protocol
+
+try:
+    unicode
+except Exception:
+    unicode = str
+
+
+def is_json_basic_type(obj):
+    """Checks if the object is an int, float, bool, or str."""
+    if isinstance(obj, (int, float, bool, str)):
+        return True
+    return sys.version_info < (3,) and isinstance(obj, unicode)
+
+
+def handle_null_fields(obj, obj_field_name=None):
+    """Removes fields with a 'None' value.
+
+    The LS Client in VS Code expects optional fields that are not needed
+    to be omitted. Unfortunately, pygls uses 'null' in these instances.
+    """
+    # This is a temporary workaround to address the following issues:
+    #   https://github.com/microsoft/vscode-languageserver-node/issues/740#issuecomment-773967897
+    #   https://github.com/pappasam/jedi-language-server/issues/60
+    #   https://github.com/openlawlibrary/pygls/issues/145
+    #   https://github.com/microsoft/vscode-languageserver-node/issues/740
+    if is_json_basic_type(obj):
+        return
+    elif isinstance(obj, list):
+        for o in obj:
+            handle_null_fields(o, obj_field_name)
+        return
+    elif isinstance(obj, dict):
+        for k, v in obj.items():
+            handle_null_fields(v, k)
+
+    important_attribute = lambda x: not x.startswith("_") and not callable(
+        getattr(obj, x)
+    )
+
+    for attr in filter(important_attribute, dir(obj)):
+        member = getattr(obj, attr)
+        if member is None:
+            # This is a special condition to handle VersionedTextDocumentIdentifier object.
+            # See issues:
+            # https://github.com/pappasam/jedi-language-server/issues/61
+            # https://github.com/openlawlibrary/pygls/issues/146
+            #
+            # The version field should either use `0` or the value received from `client`.
+            # Seems like using `null` or removing this causes VS Code to ignore
+            # code actions.
+            if (
+                attr == "version"
+                and obj_field_name == "textDocument"
+                and "uri" in dir(obj)
+            ):
+                setattr(obj, "version", 0)
+            else:
+                delattr(obj, attr)
+
+        elif is_json_basic_type(member):
+            continue
+
+        else:
+            handle_null_fields(member, attr)
+
+
+def patched_without_none_fields(resp):
+    """Monkeypatch for `JsonRPCResponseMessage.without_none_fields` to remove `None` results."""
+    if resp.error is None:
+        del resp.error
+        if hasattr(resp, "result"):
+            handle_null_fields(resp.result)
+    else:
+        del resp.result
+    return resp
+
+
+pygls.protocol.JsonRPCResponseMessage.without_none_fields = patched_without_none_fields
+
+
 from jedi_language_server.cli import cli
 
 sys.exit(cli())