From c82fab97c171cf56d07a6cf8638442bc8b5c14f8 Mon Sep 17 00:00:00 2001
From: MischaPanch <mischa.panch@gmail.com>
Date: Thu, 14 Aug 2025 11:47:46 +0200
Subject: [PATCH] CSharp: added waiting for request_referencing and test for
 cross-file references

---
 .../csharp_language_server.py                 |  9 +++++
 .../repos/csharp/test_repo/Models/Person.cs   |  8 +++++
 test/solidlsp/csharp/test_csharp_basic.py     | 33 +++++++++++++++++++
 3 files changed, 50 insertions(+)

diff --git a/src/solidlsp/language_servers/csharp_language_server.py b/src/solidlsp/language_servers/csharp_language_server.py
index 6878901f..870e21a0 100644
--- a/src/solidlsp/language_servers/csharp_language_server.py
+++ b/src/solidlsp/language_servers/csharp_language_server.py
@@ -13,6 +13,7 @@ import threading
 import urllib.request
 import zipfile
 from pathlib import Path
+from time import sleep
 from typing import cast
 
 from overrides import override
@@ -21,6 +22,7 @@ from solidlsp.ls import SolidLanguageServer
 from solidlsp.ls_config import LanguageServerConfig
 from solidlsp.ls_exceptions import SolidLSPException
 from solidlsp.ls_logger import LanguageServerLogger
+from solidlsp.ls_types import Location
 from solidlsp.ls_utils import PathUtils
 from solidlsp.lsp_protocol_handler.lsp_types import InitializeParams
 from solidlsp.lsp_protocol_handler.server import ProcessLaunchInfo
@@ -735,3 +737,10 @@ class CSharpLanguageServer(SolidLanguageServer):
             project_uris = [PathUtils.path_to_uri(project_file) for project_file in project_files]
             self.server.notify.send_notification("project/open", {"projects": project_uris})
             self.logger.log(f"Opened project files: {project_files}", logging.DEBUG)
+
+    @override
+    def request_references(self, relative_file_path: str, line: int, column: int) -> list[Location]:
+        # Like in the typescript LS, we need to wait here for the language server to
+        # get correct results that include cross-file references.
+        sleep(1)
+        return super().request_references(relative_file_path, line, column)
diff --git a/test/resources/repos/csharp/test_repo/Models/Person.cs b/test/resources/repos/csharp/test_repo/Models/Person.cs
index c771195c..db101886 100644
--- a/test/resources/repos/csharp/test_repo/Models/Person.cs
+++ b/test/resources/repos/csharp/test_repo/Models/Person.cs
@@ -1,3 +1,5 @@
+using TestProject;
+
 namespace TestProject.Models
 {
     public class Person
@@ -22,5 +24,11 @@ namespace TestProject.Models
         {
             return Age >= 18;
         }
+        
+        public int CalculateYearsUntilRetirement()
+        {
+            var calculator = new Calculator();
+            return calculator.Subtract(65, Age);
+        }
     }
 }
\ No newline at end of file
diff --git a/test/solidlsp/csharp/test_csharp_basic.py b/test/solidlsp/csharp/test_csharp_basic.py
index 89d3caea..a0c83a13 100644
--- a/test/solidlsp/csharp/test_csharp_basic.py
+++ b/test/solidlsp/csharp/test_csharp_basic.py
@@ -87,6 +87,39 @@ class TestCSharpLanguageServer:
         assert "ToString" in symbol_names
         assert "IsAdult" in symbol_names
 
+    @pytest.mark.parametrize("language_server", [Language.CSHARP], indirect=True)
+    def test_find_referencing_symbols_across_files(self, language_server: SolidLanguageServer) -> None:
+        """Test finding references to Calculator.Subtract method across files."""
+        # First, find the Subtract method in Program.cs
+        file_path = os.path.join("Program.cs")
+        symbols = language_server.request_document_symbols(file_path)
+
+        # Flatten the symbols if they're nested
+        symbol_list = symbols[0] if symbols and isinstance(symbols[0], list) else symbols
+
+        subtract_symbol = None
+        for sym in symbol_list:
+            if sym.get("name") == "Subtract":
+                subtract_symbol = sym
+                break
+
+        assert subtract_symbol is not None, "Could not find 'Subtract' method symbol in Program.cs"
+
+        # Get references to the Subtract method
+        sel_start = subtract_symbol["selectionRange"]["start"]
+        refs = language_server.request_references(file_path, sel_start["line"], sel_start["character"] + 1)
+
+        # Should find references in both Program.cs and Models/Person.cs
+        ref_files = [ref.get("relativePath", "") for ref in refs]
+        print(f"Found references: {refs}")
+        print(f"Reference files: {ref_files}")
+
+        # Check that we have references from both files
+        assert any("Program.cs" in ref_file for ref_file in ref_files), "Should find reference in Program.cs"
+        assert any(
+            "Models/Person.cs" in ref_file for ref_file in ref_files
+        ), "Should find reference in Models/Person.cs where Calculator.Subtract is called"
+
 
 @pytest.mark.csharp
 class TestCSharpSolutionProjectOpening: