fix: Extend Nix symbol ranges to avoid additional semicolon

Add _extend_nix_symbol_range_to_include_semicolon method to prevent
double semicolons
Add test_nix_symbol_replacement_no_double_semicolon to validate the fix

src/solidlsp/language_servers/nixd_ls.py

@@ -15,6 +15,7 @@ from pathlib import Path
 
 from overrides import override
 
+from solidlsp import ls_types
 from solidlsp.ls import SolidLanguageServer
 from solidlsp.ls_config import LanguageServerConfig
 from solidlsp.ls_logger import LanguageServerLogger
@@ -28,6 +29,79 @@ class NixLanguageServer(SolidLanguageServer):
     Provides Nix specific instantiation of the LanguageServer class using nixd.
     """
 
+    def _extend_nix_symbol_range_to_include_semicolon(
+        self, symbol: ls_types.UnifiedSymbolInformation, file_content: str
+    ) -> ls_types.UnifiedSymbolInformation:
+        """
+        Extend symbol range to include trailing semicolon for Nix attribute symbols.
+
+        nixd provides ranges that exclude semicolons (expression-level), but serena needs
+        statement-level ranges that include semicolons for proper replacement.
+        """
+        range_info = symbol["range"]
+        end_line = range_info["end"]["line"]
+        end_char = range_info["end"]["character"]
+
+        # Split file content into lines
+        lines = file_content.split("\n")
+        if end_line >= len(lines):
+            return symbol
+
+        line = lines[end_line]
+
+        # Check if there's a semicolon immediately after the current range end
+        if end_char < len(line) and line[end_char] == ";":
+            # Extend range to include the semicolon
+            new_range = {"start": range_info["start"], "end": {"line": end_line, "character": end_char + 1}}
+
+            # Create modified symbol with extended range
+            extended_symbol = symbol.copy()
+            extended_symbol["range"] = new_range
+
+            # CRITICAL: Also update the location.range if it exists
+            if extended_symbol.get("location"):
+                location = extended_symbol["location"].copy()
+                if "range" in location:
+                    location["range"] = new_range.copy()
+                extended_symbol["location"] = location
+
+            return extended_symbol
+
+        return symbol
+
+    @override
+    def request_document_symbols(
+        self, relative_file_path: str, include_body: bool = False
+    ) -> tuple[list[ls_types.UnifiedSymbolInformation], list[ls_types.UnifiedSymbolInformation]]:
+        """
+        Override to extend Nix symbol ranges to include trailing semicolons.
+
+        nixd provides expression-level ranges (excluding semicolons) but serena needs
+        statement-level ranges (including semicolons) for proper symbol replacement.
+        """
+        # Get symbols from parent implementation
+        all_symbols, root_symbols = super().request_document_symbols(relative_file_path, include_body)
+
+        # Get file content for range extension
+        file_content = self.language_server.retrieve_full_file_content(relative_file_path)
+
+        # Extend ranges for all symbols recursively
+        def extend_symbol_and_children(symbol: ls_types.UnifiedSymbolInformation) -> ls_types.UnifiedSymbolInformation:
+            # Extend this symbol's range
+            extended = self._extend_nix_symbol_range_to_include_semicolon(symbol, file_content)
+
+            # Extend children recursively
+            if extended.get("children"):
+                extended["children"] = [extend_symbol_and_children(child) for child in extended["children"]]
+
+            return extended
+
+        # Apply range extension to all symbols
+        extended_all_symbols = [extend_symbol_and_children(sym) for sym in all_symbols]
+        extended_root_symbols = [extend_symbol_and_children(sym) for sym in root_symbols]
+
+        return extended_all_symbols, extended_root_symbols
+
     @override
     def is_ignored_dirname(self, dirname: str) -> bool:
         # For Nix projects, we should ignore:

test/resources/repos/nix/test_repo/default.nix

@@ -1,56 +1,56 @@
 # default.nix - Traditional Nix expression for backwards compatibility
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import <nixpkgs> { } }:
 
 let
   # Import library functions
   lib = pkgs.lib;
   stdenv = pkgs.stdenv;
-  
+
   # Import our custom utilities
   utils = import ./lib/utils.nix { inherit lib; };
-  
+
   # Custom function to create a greeting
   makeGreeting = name: "Hello, ${name}!";
-  
+
   # List manipulation functions (using imported utils)
   listUtils = {
     double = list: map (x: x * 2) list;
     sum = list: lib.foldl' (acc: x: acc + x) 0 list;
-    average = list: 
-      if list == [] 
-      then 0 
+    average = list:
+      if list == [ ]
+      then 0
       else (listUtils.sum list) / (builtins.length list);
     # Use function from imported utils
     unique = utils.lists.unique;
   };
-  
+
   # String utilities
   stringUtils = rec {
-    capitalize = str: 
+    capitalize = str:
       let
         first = lib.substring 0 1 str;
         rest = lib.substring 1 (-1) str;
       in
-        (lib.toUpper first) + rest;
-    
+      (lib.toUpper first) + rest;
+
     repeat = n: str: lib.concatStrings (lib.genList (_: str) n);
-    
+
     padLeft = width: char: str:
       let
         len = lib.stringLength str;
         padding = if len >= width then 0 else width - len;
       in
-        (repeat padding char) + str;
+      (repeat padding char) + str;
   };
-  
+
   # Package builder helper
   buildSimplePackage = { name, version, script }:
     stdenv.mkDerivation {
       pname = name;
       inherit version;
-      
+
       phases = [ "installPhase" ];
-      
+
       installPhase = ''
         mkdir -p $out/bin
         cat > $out/bin/${name} << EOF
@@ -61,13 +61,14 @@ let
       '';
     };
 
-in rec {
+in
+rec {
   # Export utilities
   inherit listUtils stringUtils makeGreeting;
-  
+
   # Export imported utilities directly
   inherit (utils) math strings;
-  
+
   # Example packages
   hello = buildSimplePackage {
     name = "hello";
@@ -76,7 +77,7 @@ in rec {
       echo "${makeGreeting "World"}"
     '';
   };
-  
+
   calculator = buildSimplePackage {
     name = "calculator";
     version = "0.1";
@@ -95,7 +96,7 @@ in rec {
       esac
     '';
   };
-  
+
   # Environment with multiple packages
   devEnv = pkgs.buildEnv {
     name = "dev-environment";
@@ -107,7 +108,7 @@ in rec {
       calculator
     ];
   };
-  
+
   # Shell derivation
   shell = pkgs.mkShell {
     buildInputs = with pkgs; [
@@ -117,20 +118,20 @@ in rec {
       gnugrep
       gnused
     ];
-    
+
     shellHook = ''
       echo "Entering Nix shell environment"
       echo "Available custom functions: makeGreeting, listUtils, stringUtils"
     '';
   };
-  
+
   # Configuration example
   config = {
     system = {
       stateVersion = "23.11";
       enable = true;
     };
-    
+
     services = {
       nginx = {
         enable = false;
@@ -144,7 +145,7 @@ in rec {
         };
       };
     };
-    
+
     users = {
       testUser = {
         name = "test";
@@ -154,7 +155,7 @@ in rec {
       };
     };
   };
-  
+
   # Recursive attribute set example
   tree = {
     root = {
@@ -170,13 +171,13 @@ in rec {
         right = { value = 7; };
       };
     };
-    
+
     # Tree traversal function
     traverse = node:
       if node ? left && node ? right
       then [ node.value ] ++ (tree.traverse node.left) ++ (tree.traverse node.right)
       else if node ? value
       then [ node.value ]
-      else [];
+      else [ ];
   };
-}
+}

test/serena/test_symbol_editing.py

@@ -1,6 +1,7 @@
 import logging
 import os
 import shutil
+import sys
 import tempfile
 import time
 from abc import abstractmethod
@@ -443,3 +444,42 @@ class ReplaceBodyTest(EditingTest):
 )
 def test_replace_body(test_case: ReplaceBodyTest, snapshot):
     test_case.run_test(content_after_ground_truth=snapshot)
+
+
+NIX_ATTR_REPLACEMENT = """c = 3;"""
+
+
+class NixAttrReplacementTest(EditingTest):
+    """Test for replacing individual attributes in Nix that should NOT result in double semicolons."""
+
+    def __init__(self, language: Language, rel_path: str, symbol_name: str, new_body: str):
+        super().__init__(language, rel_path)
+        self.symbol_name = symbol_name
+        self.new_body = new_body
+
+    def _apply_edit(self, code_editor: CodeEditor) -> None:
+        code_editor.replace_body(self.symbol_name, self.rel_path, self.new_body)
+
+
+@pytest.mark.nix
+@pytest.mark.skipif(sys.platform == "win32", reason="nixd language server doesn't run on Windows")
+def test_nix_symbol_replacement_no_double_semicolon(snapshot):
+    """
+    Test that replacing a Nix attribute does not result in double semicolons.
+
+    This test exercises the bug where:
+    - Original: users.users.example = { isSystemUser = true; group = "example"; description = "Example service user"; };
+    - Replacement: c = 3;
+    - Bug result would be: c = 3;; (double semicolon)
+    - Correct result should be: c = 3; (single semicolon)
+
+    The replacement body includes a semicolon, but the language server's range extension
+    logic should prevent double semicolons.
+    """
+    test_case = NixAttrReplacementTest(
+        Language.NIX,
+        "default.nix",
+        "testUser",  # Simple attrset with multiple key-value pairs
+        NIX_ATTR_REPLACEMENT,
+    )
+    test_case.run_test(content_after_ground_truth=snapshot)

test/solidlsp/nix/test_nix_basic.py

@@ -106,14 +106,14 @@ class TestNixLanguageServer:
 
         assert refs is not None
         assert isinstance(refs, list)
-        # nixd finds at least the inherit statement (line 66)
+        # nixd finds at least the inherit statement (line 67)
         assert len(refs) >= 1, f"Should find at least 1 reference to makeGreeting, found {len(refs)}"
 
         # Verify makeGreeting is referenced at expected locations
         if refs:
             ref_lines = sorted([ref["range"]["start"]["line"] for ref in refs])
-            # Check if we found the inherit (line 66, 0-indexed: 65)
-            assert 65 in ref_lines, f"Should find makeGreeting inherit at line 66, found at lines {[l+1 for l in ref_lines]}"
+            # Check if we found the inherit (line 67, 0-indexed: 66)
+            assert 66 in ref_lines, f"Should find makeGreeting inherit at line 67, found at lines {[l+1 for l in ref_lines]}"
 
     @pytest.mark.parametrize("language_server", [Language.NIX], indirect=True)
     def test_hover_information(self, language_server: SolidLanguageServer) -> None: