use valid_fnames to improve find_filename

aider/coders/editblock_coder.py

@@ -23,7 +23,13 @@ class EditBlockCoder(Coder):
         content = self.partial_response_content
 
         # might raise ValueError for malformed ORIG/UPD blocks
-        edits = list(find_original_update_blocks(content, self.fence))
+        edits = list(
+            find_original_update_blocks(
+                content,
+                self.fence,
+                self.get_inchat_relative_files(),
+            )
+        )
 
         self.shell_commands += [edit[1] for edit in edits if edit[0] is None]
         edits = [edit for edit in edits if edit[0] is not None]
@@ -414,7 +420,7 @@ def strip_filename(filename, fence):
     return filename
 
 
-def find_original_update_blocks(content, fence=DEFAULT_FENCE):
+def find_original_update_blocks(content, fence=DEFAULT_FENCE, valid_fnames=None):
     lines = content.splitlines(keepends=True)
     i = 0
     current_filename = None
@@ -454,7 +460,7 @@ def find_original_update_blocks(content, fence=DEFAULT_FENCE):
         # Check for SEARCH/REPLACE blocks
         if line.strip() == HEAD:
             try:
-                filename = find_filename(lines[max(0, i - 3) : i], fence)
+                filename = find_filename(lines[max(0, i - 3) : i], fence, valid_fnames)
                 if not filename:
                     if current_filename:
                         filename = current_filename
@@ -491,7 +497,7 @@ def find_original_update_blocks(content, fence=DEFAULT_FENCE):
         i += 1
 
 
-def find_filename(lines, fence):
+def find_filename(lines, fence, valid_fnames):
     """
     Deepseek Coder v2 has been doing this:
 
@@ -505,19 +511,50 @@ def find_filename(lines, fence):
 
     This is a more flexible search back for filenames.
     """
+
+    if valid_fnames is None:
+        valid_fnames = []
+
     # Go back through the 3 preceding lines
     lines.reverse()
     lines = lines[:3]
 
+    filenames = []
     for line in lines:
         # If we find a filename, done
         filename = strip_filename(line, fence)
         if filename:
-            return filename
+            filenames.append(filename)
 
         # Only continue as long as we keep seeing fences
         if not line.startswith(fence[0]):
-            return
+            break
+
+    if not len(filenames):
+        return
+
+    if len(filenames) == 1:
+        return filenames[0]
+
+    # pick the *best* filename found
+
+    # pick a valid fname
+    for fname in filenames:
+        if fname in valid_fnames:
+            return fname
+
+    # match just on basename, return full valid fname
+    for fname in filenames:
+        for vfn in valid_fnames:
+            if fname == vfn.name:
+                return vfn
+
+    # look for a file w/extension
+    for fname in filenames:
+        if "." in fname:
+            return fname
+
+    return filenames[0]
 
 
 def find_similar_lines(search_lines, content_lines, threshold=0.6):