fix(native): escape markers in edit_file

Author: ravitemer

lua/mcphub/native/neovim/files/edit_file/diff_parser.lua

@@ -295,6 +295,7 @@ end
 
 function DiffParser:unescape_markers(line)
     local newline = line:gsub("^%s*\\<<<<<", "<<<<<<"):gsub("^%s*\\=====", "====="):gsub("^%s*\\>>>>>", ">>>>>")
+    newline = newline:gsub("^%s*\\\\<<<<<", "<<<<<<"):gsub("^%s*\\\\=====", "====="):gsub("^%s*\\\\>>>>>", ">>>>>")
     return newline
 end
 

lua/mcphub/native/neovim/files/edit_file/edit_session.lua

@@ -103,6 +103,7 @@ function EditSession:start(options)
 
     ---@type ParsedBlock[]
     local parsed_blocks = {}
+    --- Needed to avoid parsing error when the file content has markers
     if is_replacing_entire_file then
         table.insert(parsed_blocks, {
             block_id = "Block 1",
@@ -124,13 +125,23 @@ function EditSession:start(options)
             if #parsed_blocks > 1 then
                 return self:_handle_error(
                     string.format(
-                        "## A Block with empty search content found, but multiple blocks are present in the diff. %s will replace the entire file. If you want to write the entire file, please use a single SEARCH/REPLACE block with empty SEARCH content. If you want to replace a section of the file, please provide non-whitespace SEARCH content.",
+                        "A Block with empty search content found, but multiple blocks are present in the diff. %s will replace the entire file. If you want to write the entire file, please use a single SEARCH/REPLACE block with empty SEARCH content. If you want to replace a section of the file, please provide non-whitespace SEARCH content.",
                         block.block_id
                     )
                 )
             end
             is_replacing_entire_file = true
             break
+        else
+            -- If we are searching for something in a file that doesn't exist, we should not proceed
+            if file_content == "" then
+                return self:_handle_error(
+                    string.format(
+                        "Editing `%s` failed. The file does not exist. If you are using relative paths make sure the path is relative to the cwd or use an absolute path.",
+                        self.file_path
+                    )
+                )
+            end
         end
     end
 

lua/mcphub/native/neovim/files/edit_file/init.lua

@@ -39,7 +39,6 @@ IMPORTANT: The tool is NEVER wrong. Once edits are shown in the buffer, user mig
 CRITICAL: 
 - When there are two or more related changes needed in a file, always use multiple SEARCH/REPLACE blocks in the diff from the start of the file to the end. Each block should contain the exact content to find and the new content to replace it with. Failing to do so or using multiple calls with single SEARCH/REPLACE block will result in you being fired!!!
 - The markers `<<<<<<< SEARCH`, `=======`, and `>>>>>>> REPLACE` MUST be exact with no other characters on the line.
-- When the SEARCH or REPLACE content includes lines that start with markers like `<<<<<<<`, `=======`, or `>>>>>>>`, you MUST escape them by adding a backslash before each marker so that tool doesn't parse them as actual markers. For example, to search for content that has `<<<<<<< SEARCH`, use `\<<<<<<< SEARCH` in the SEARCH block.
 
 
 Examples:
@@ -112,6 +111,9 @@ print("Count is", count)
 print("Counter is", counter)
 >>>>>>> REPLACE
 
+CRITICAL RULE:
+When the SEARCH or REPLACE content includes lines that start with markers like `<<<<<<<`, `=======`, or `>>>>>>>`, you MUST escape them by adding a backslash before each marker so that tool doesn't parse them as actual markers. For example, to search for content that has `<<<<<<< SEARCH`, use `\<<<<<<< SEARCH` in the SEARCH block.
+
 5. Escaping markers in SEARCH/REPLACE content:
 <<<<<<< SEARCH
 Tutorial:

tests/native/neovim/files/edit_file/test_diff_parser.lua

@@ -196,7 +196,7 @@ local y = 3
     eq(error, nil)
     eq(#blocks, 1)
     local block = blocks[1]
-    eq(block.search_lines[2] == "<<<<<<<< SEARCH", true)
+    eq(block.search_lines[2], "<<<<<<<< SEARCH")
 end
 
 -- Group 2: Malformed Input and Issue Tracking