1 files changed, 16 insertions, 14 deletions
diff --git a/src/debputy/lsp/lsp_dispatch.py b/src/debputy/lsp/lsp_dispatch.py
index b63f30c..5d09a44 100644
--- a/src/debputy/lsp/lsp_dispatch.py
+++ b/src/debputy/lsp/lsp_dispatch.py
@@ -10,6 +10,7 @@ from typing import (
     Mapping,
     List,
     Tuple,
+    Literal,
 )
 
 from lsprotocol.types import (
@@ -75,21 +76,22 @@ def is_doc_at_version(uri: str, version: int) -> bool:
     return dv == version
 
 
-def determine_language_id(doc: "TextDocument") -> Tuple[str, str]:
-    lang_id = doc.language_id
-    if lang_id and not lang_id.isspace():
-        return "declared", lang_id
-    path = doc.path
-    try:
-        last_idx = path.rindex("debian/")
-    except ValueError:
-        return "filename", os.path.basename(path)
-    guess_language_id = path[last_idx:]
-    return "filename", guess_language_id
+@DEBPUTY_LANGUAGE_SERVER.feature(TEXT_DOCUMENT_DID_OPEN)
+async def _open_document(
+    ls: "DebputyLanguageServer",
+    params: DidChangeTextDocumentParams,
+) -> None:
+    await _open_or_changed_document(ls, params)
 
 
-@DEBPUTY_LANGUAGE_SERVER.feature(TEXT_DOCUMENT_DID_OPEN)
 @DEBPUTY_LANGUAGE_SERVER.feature(TEXT_DOCUMENT_DID_CHANGE)
+async def _changed_document(
+        ls: "DebputyLanguageServer",
+        params: DidChangeTextDocumentParams,
+) -> None:
+    await _open_or_changed_document(ls, params)
+
+
 async def _open_or_changed_document(
     ls: "DebputyLanguageServer",
     params: Union[DidOpenTextDocumentParams, DidChangeTextDocumentParams],
@@ -99,7 +101,7 @@ async def _open_or_changed_document(
     doc = ls.workspace.get_text_document(doc_uri)
 
     _DOCUMENT_VERSION_TABLE[doc_uri] = version
-    id_source, language_id = determine_language_id(doc)
+    id_source, language_id = ls.determine_language_id(doc)
     handler = DIAGNOSTIC_HANDLERS.get(language_id)
     if handler is None:
         _info(
@@ -214,7 +216,7 @@ def _dispatch_standard_handler(
 ) -> R:
     doc = ls.workspace.get_text_document(doc_uri)
 
-    id_source, language_id = determine_language_id(doc)
+    id_source, language_id = ls.determine_language_id(doc)
     handler = handler_table.get(language_id)
     if handler is None:
         _info(