fix(tools): read_files tool can read entire file if end_line is greater than total lines (#1824)

Eckii24 · web-flow · commit 562950d1584a · 2025-07-12T11:16:00.000+01:00
diff --git a/lua/codecompanion/strategies/chat/agents/tools/read_file.lua b/lua/codecompanion/strategies/chat/agents/tools/read_file.lua
@@ -64,16 +64,6 @@ start_line_number_base_zero (%d) is beyond file length. File `%s` has %d lines (
       #lines,
       math.max(0, #lines - 1)
     )
-  elseif end_line_zero ~= -1 and end_line_zero >= #lines then
-    error_msg = fmt(
-      [[Error reading `%s`
-end_line_number_base_zero (%d) is beyond file length. File `%s` has %d lines (0-%d)]],
-      action.filepath,
-      end_line_zero,
-      action.filepath,
-      #lines,
-      math.max(0, #lines - 1)
-    )
   elseif end_line_zero ~= -1 and start_line_zero > end_line_zero then
     error_msg = fmt(
       [[Error reading `%s`
@@ -96,6 +86,11 @@ Invalid line range - start_line_number_base_zero (%d) comes after end_line_numbe
     }
   end
 
+  -- Clamp end_line_zero to the last valid line if it exceeds file length (unless -1)
+  if not error_msg and end_line_zero ~= -1 and end_line_zero >= #lines then
+    end_line_zero = math.max(0, #lines - 1)
+  end
+
   -- Convert to 1-based indexing
   local start_line = start_line_zero + 1
   local end_line = end_line_zero == -1 and #lines or end_line_zero + 1
diff --git a/tests/strategies/chat/agents/tools/test_read_file.lua b/tests/strategies/chat/agents/tools/test_read_file.lua
@@ -85,6 +85,36 @@ T["can read all of the file"] = function()
   h.eq("beta", string.match(output, "beta"))
   h.eq("gamma", string.match(output, "gamma"))
 end
+T["clamps end_line_number_base_zero to file length if it is too large"] = function()
+  child.lua([[
+    vim.uv.chdir(_G.TEST_CWD)
+    local contents = { "one", "two", "three", "four", "five" }
+    local ok = vim.fn.writefile(contents, _G.TEST_TMPFILE_ABSOLUTE)
+    assert(ok == 0)
+
+    -- end_line_number_base_zero is way beyond file length (file has 5 lines, 0-based: 0-4)
+    local tool = {
+      {
+        ["function"] = {
+          name = "read_file",
+          arguments = string.format(
+            '{"filepath": "%s", "start_line_number_base_zero": 1, "end_line_number_base_zero": 10}',
+            vim.fs.joinpath(_G.TEST_DIR, _G.TEST_TMPFILE)
+          )
+        },
+      },
+    }
+    agent:execute(chat, tool)
+    vim.wait(200)
+  ]])
+
+  local output = child.lua_get("chat.messages[#chat.messages].content")
+  h.eq("two", string.match(output, "two"))
+  h.eq("three", string.match(output, "three"))
+  h.eq("four", string.match(output, "four"))
+  h.eq("five", string.match(output, "five"))
+  h.not_eq("one", string.match(output, "one")) -- since we started at line 1
+end
 
 T["can only read files that exist"] = function()
   child.lua([[
