Fix: SearchForPatternTool returned 1-based line numbers (in contrast to all other tools)

Cause: Implementation of text_utils.search_text

Serena's tools use 0-based line numbers, and this information
is now also centrally added to the instructions (manual).

CHANGELOG.md

@@ -25,6 +25,7 @@ Status of the `main` branch. Changes prior to the next official version change w
   - Project server: 
      - `query_project`: Support use of project root instead of project name #1388
      - `list_queryable_projects`: Return both project names and project roots 
+  - Fix: `search_for_pattern` tool returned 1-based line numbers (in contrast to all other tools); cause: implementation of `text_utils.search_text`
 
 * JetBrains:
   - `Move` and `SafeDelete` tools: transform empty string to None (counteracts client errors)

src/serena/resources/config/prompt_templates/system_prompt.yml

@@ -41,7 +41,9 @@ prompts:
     The following global (not project-specific) memories are available to you: {{ global_memories_list }}
     {%- endif -%}
     {%- endif %}
-
+    
+    Line numbers returned by Serena's tools are 0-based!
+    
     The context and modes of operation are described below. These determine how to interact with your user
     and which kinds of interactions are expected of you.
 

src/serena/tools/file_tools.py

@@ -347,7 +347,6 @@ class SearchForPatternTool(Tool):
             is used to further restrict the search).
             Smartly combining the various restrictions allows you to perform very targeted searches.
 
-
         :param substring_pattern: Regular expression for a substring pattern to search for
         :param context_lines_before: Number of lines of context to include before each match
         :param context_lines_after: Number of lines of context to include after each match
@@ -373,7 +372,7 @@ class SearchForPatternTool(Tool):
             For example, for finding classes or methods from a name pattern.
             Setting to False is a better choice if you also want to search in non-code files, like in html or yaml files,
             which is why it is the default.
-        :return: A mapping of file paths to lists of matched consecutive lines.
+        :return: A mapping from file paths to matched consecutive lines (0-based line numbers).
         """
         abs_path = os.path.join(self.get_project_root(), relative_path)
         if not os.path.exists(abs_path):
@@ -411,6 +410,7 @@ class SearchForPatternTool(Tool):
                 paths_include_glob=paths_include_glob,
                 paths_exclude_glob=paths_exclude_glob,
             )
+
         # group matches by file
         file_to_matches: dict[str, list[str]] = defaultdict(list)
         for match in matches:

src/serena/util/text_utils.py

@@ -188,17 +188,16 @@ def search_text(
             end_pos = match.end()
 
             # Find the line numbers for the start and end positions
-            start_line_num = content[:start_pos].count("\n") + 1
-            end_line_num = content[:end_pos].count("\n") + 1
+            start_line_num = content[:start_pos].count("\n")
+            end_line_num = content[:end_pos].count("\n")
 
             # Calculate the range of lines to include in the context
-            context_start = max(1, start_line_num - context_lines_before)
-            context_end = min(total_lines, end_line_num + context_lines_after)
+            context_start = max(0, start_line_num - context_lines_before)
+            context_end = min(total_lines - 1, end_line_num + context_lines_after)
 
             # Create TextLine objects for the context
             context_lines = []
-            for i in range(context_start - 1, context_end):
-                line_num = i + 1
+            for line_num in range(context_start, context_end + 1):
                 if context_start <= line_num < start_line_num:
                     match_type = LineType.BEFORE_MATCH
                 elif end_line_num < line_num <= context_end:
@@ -206,7 +205,7 @@ def search_text(
                 else:
                     match_type = LineType.MATCH
 
-                context_lines.append(TextLine(line_number=line_num, line_content=lines[i], match_type=match_type))
+                context_lines.append(TextLine(line_number=line_num, line_content=lines[line_num], match_type=match_type))
 
             matches.append(MatchedConsecutiveLines(lines=context_lines, source_file_path=source_file_path))
     else:
@@ -215,7 +214,6 @@ def search_text(
         # Search line by line, normal compile without DOTALL
         compiled_pattern = re.compile(pattern)
         for i, line in enumerate(lines):
-            line_num = i + 1
             if compiled_pattern.search(line):
                 # Calculate the range of lines to include in the context
                 context_start = max(0, i - context_lines_before)
@@ -224,7 +222,6 @@ def search_text(
                 # Create TextLine objects for the context
                 context_lines = []
                 for j in range(context_start, context_end + 1):
-                    context_line_num = j + 1
                     if j < i:
                         match_type = LineType.BEFORE_MATCH
                     elif j > i:
@@ -232,7 +229,7 @@ def search_text(
                     else:
                         match_type = LineType.MATCH
 
-                    context_lines.append(TextLine(line_number=context_line_num, line_content=lines[j], match_type=match_type))
+                    context_lines.append(TextLine(line_number=j, line_content=lines[j], match_type=match_type))
 
                 matches.append(MatchedConsecutiveLines(lines=context_lines, source_file_path=source_file_path))