Mark deprecated rangeLength optional in TextDocumentContentChangeEvent

CHANGELOG.md

@@ -15,11 +15,13 @@ and this project adheres to [Semantic Versioning][semver].
 ### Changed
 
 - Exit server normally when `ctrl+c` is pressed in command shell.
+- Mark deprecated `rangeLength` optional in `TextDocumentContentChangeEvent` ([#123])
 - Optimize json-rpc message serialization ([#120])
 - Fix `__init__()` constructors in several interface types ([#125])
 - Fix valueSet type in `SymbolKindAbstract` ([#125])
 
 [#125]: https://github.com/openlawlibrary/pygls/pull/125
+[#123]: https://github.com/openlawlibrary/pygls/pull/123
 [#120]: https://github.com/openlawlibrary/pygls/pull/120
 [#117]: https://github.com/openlawlibrary/pygls/pull/117
 

pygls/types.py

@@ -1198,7 +1198,10 @@ def __init__(self,
 
 
 class TextDocumentContentChangeEvent:
-    def __init__(self, range: 'Range', range_length: NumType, text: str):
+    def __init__(self,
+                 range: 'Range',
+                 range_length: Optional[NumType] = None,
+                 text: str = ''):
         self.range = range
         self.rangeLength = range_length
         self.text = text

pygls/workspace.py

@@ -219,6 +219,7 @@ def _apply_none_change(self, change: TextDocumentContentChangeEvent) -> None:
 
         Currently does nothing, provided for consistency.
         """
+        pass
 
     def apply_change(self, change: TextDocumentContentChangeEvent) -> None:
         """Apply a text change to a document, considering TextDocumentSyncKind
@@ -232,30 +233,11 @@ def apply_change(self, change: TextDocumentContentChangeEvent) -> None:
             both Range and RangeLength from their request. Consequently, the
             attributes "range" and "rangeLength" will be missing from FULL
             content update client requests in the pygls Python library.
-
-        Improvements:
-            Consider revising our treatment of TextDocumentContentChangeEvent,
-            and all other LSP primitive types, to set "Optional" interface
-            attributes from the client to "None". The "hasattr" check is
-            admittedly quite ugly; while it is appropriate given our current
-            state, there are plenty of improvements to be made. A good place to
-            start: require more rigorous de-serialization efforts when reading
-            client requests in protocol.py.
         """
-        if (
-            hasattr(change, 'range') and
-            hasattr(change, 'rangeLength') and
-            self._is_sync_kind_incremental
-        ):
-            self._apply_incremental_change(change)
-        elif self._is_sync_kind_none:
-            self._apply_none_change(change)
-        elif not (
-            hasattr(change, 'range') or
-            hasattr(change, 'rangeLength')
-        ):
-            self._apply_full_change(change)
-        else:
+        if hasattr(change, 'range'):
+            if self._is_sync_kind_incremental:
+                self._apply_incremental_change(change)
+                return
             # Log an error, but still perform full update to preserve existing
             # assumptions in test_document/test_document_full_edit. Test breaks
             # otherwise, and fixing the tests would require a broader fix to
@@ -264,6 +246,10 @@ def apply_change(self, change: TextDocumentContentChangeEvent) -> None:
                 "Unsupported client-provided TextDocumentContentChangeEvent. "
                 "Please update / submit a Pull Request to your LSP client."
             )
+
+        if self._is_sync_kind_none:
+            self._apply_none_change(change)
+        else:
             self._apply_full_change(change)
 
     @property

tests/test_document.py

@@ -66,6 +66,14 @@ def test_document_full_edit():
         "print a, b"
     ]
 
+    doc = Document('file:///uri', u''.join(old), sync_kind=TextDocumentSyncKind.FULL)
+    change = TextDocumentContentChangeEvent(range=None, text=u'print a, b')
+    doc.apply_change(change)
+
+    assert doc.lines == [
+        "print a, b"
+    ]
+
 
 def test_document_line_edit():
     doc = Document('file:///uri', u'itshelloworld')
@@ -96,6 +104,16 @@ def test_document_multiline_edit():
         "    print a, b\n"
     ]
 
+    doc = Document('file:///uri', u''.join(old), sync_kind=TextDocumentSyncKind.INCREMENTAL)
+    change = TextDocumentContentChangeEvent(
+        range=Range(Position(1, 4), Position(2, 11)), text=u'print a, b')
+    doc.apply_change(change)
+
+    assert doc.lines == [
+        "def hello(a, b):\n",
+        "    print a, b\n"
+    ]
+
 
 def test_document_no_edit():
     old = [