Aider-AI/aider · error · DiffError

Duplicate action for file: {path}

Error message

Duplicate action for file: {path}

What it means

Raised during patch parsing when an '*** Add File: <path>' block uses a path that already has an entry in patch.actions. Unlike deletes (where exact duplicates are ignored with a warning), add actions are strictly unique per path.

Source

Thrown at aider/coders/patch_coder.py:385

                        continue
                    else:
                        raise DiffError(f"Conflicting actions for file: {path}")
                if path not in current_files:
                    raise DiffError(
                        f"Delete File Error - file not found: {path}"
                    )  # Check against known files

                patch.actions[path] = PatchAction(type=ActionType.DELETE, path=path)
                continue

            # ---------- ADD ---------- #
            elif norm_line.startswith("*** Add File: "):
                path = norm_line[len("*** Add File: ") :].strip()
                index += 1
                if not path:
                    raise DiffError("Add File action missing path.")
                if path in patch.actions:
                    raise DiffError(f"Duplicate action for file: {path}")
                # Check if file exists in the context provided (should not for Add).
                # Note: We only have needed files, a full check requires FS access.
                # if path in current_files:
                #     raise DiffError(f"Add File Error - file already exists: {path}")

                action, index = self._parse_add_file_content(lines, index)
                action.path = path  # Ensure path is set
                patch.actions[path] = action
                continue

            # If we are here, the line is unexpected
            # Allow blank lines between actions
            if not norm_line.strip():
                index += 1
                continue

            raise DiffError(f"Unknown or misplaced line while parsing patch: {line}")

View on GitHub (pinned to 5dc9490bb3)

Solutions

1. Merge the two Add blocks into one, keeping the intended content
2. Remove the earlier action for that path if the file should only be added
3. Retry the edit so the model produces one action per file

Example fix

// before
*** Add File: a.py
+one
*** Add File: a.py
+two

// after
*** Add File: a.py
+one
+two

from collections import Counter

def no_duplicate_adds(patch_text: str) -> bool:
    adds = [l[len("*** Add File: "):].strip() for l in patch_text.splitlines()
            if l.startswith("*** Add File: ")]
    acts = [l.split(": ", 1)[1].strip() for l in patch_text.splitlines()
            if l.startswith("*** ") and ": " in l]
    return max(Counter(acts).values(), default=0) <= 1 and not (set(adds) & (set(acts) - set(adds)))

try:
    edits = coder.get_edits(reply)
except DiffError as e:
    if "Duplicate action for file" in str(e):
        reply = merge_duplicate_add_blocks(reply)
        edits = coder.get_edits(reply)
    else:
        raise

When it happens

Trigger: Two '*** Add File: same.py' blocks in one patch; an '*** Update File: same.py' earlier in the patch followed by an Add for the same path.

Common situations: Model emits the new file twice (often when the content is long and it restarts); concatenated retries in one response; add-after-update confusion in model output.

Related errors

• Delete File action missing path.
• Add File action missing path.
• Unknown or misplaced line while parsing patch: {line}
• Invalid Add File line (missing '+'): {line}
• Bad/missing filename. The filename must be alone on the line

AI-assisted analysis of Aider-AI/aider@5dc9490bb3 (2026-08-15). Data as JSON: /api/errors/cfeee0b37a713d33. Report an issue: GitHub.