abhigyanpatwari/GitNexus · error · ValueError

committed overlay destination is unavailable: {target}

Error message

committed overlay destination is unavailable: {target}

What it means

Thrown in `committed_destination_base_digests` when `git show {commit}:{key}` fails for a target path. The promoter needs the bytes of every committed destination to hash them; if any target is missing from that commit, overflowed the byte cap, or git reported an error, the committed binding cannot be captured.

Source

Thrown at eval/workflow_bench/promotion_apply.py:551

    )
    if not rev.ok or rev.stdout_capture_overflow or rev.stdout_capture is None:
        raise ValueError("could not resolve the committed promotion base")
    commit = rev.stdout_capture.decode("ascii", errors="strict").strip()
    if not commit or any(character not in "0123456789abcdefABCDEF" for character in commit):
        raise ValueError("committed promotion base is not an immutable object id")
    bindings: dict[str, str] = {}
    for relative, _content in payload:
        for target in mirror_targets(relative):
            key = target.as_posix()
            if key in bindings:
                raise ValueError(f"duplicate overlay destination: {target}")
            result = run_managed(
                ["git", "-C", str(root), "show", f"{commit}:{key}"],
                timeout=60,
                capture_stdout_bytes=MAX_CANDIDATE_OVERLAY_BYTES + 1,
            )
            if not result.ok or result.stdout_capture_overflow or result.stdout_capture is None:
                raise ValueError(f"committed overlay destination is unavailable: {target}")
            bindings[key] = hashlib.sha256(result.stdout_capture).hexdigest()
    return bindings


def _write_recovery_artifact(
    root_descriptor: int,
    repo_root: Path,
    *,
    failure: BaseException,
    rollback_failures: list[str],
    replacements: list[dict[str, Any]],
    transaction_state: str,
) -> Path:
    recovery_name = ".wfbench-overlay-recovery-" + datetime.now(UTC).strftime("%Y%m%dT%H%M%S%fZ") + ".json"

    def descriptor_path(descriptor: int, fallback: Path) -> Path:
        try:
            return Path(os.readlink(f"/proc/self/fd/{descriptor}"))

View on GitHub (pinned to d540b00184)

Solutions

1. Confirm the file exists at that commit: `git -C <repo> cat-file -e <commit>:<path>` — if it errors, pick a ref where the file exists.
2. Check path casing and that the key uses no leading slash (`mirror_targets` produces repo-relative paths).
3. If the file is large, raise `MAX_CANDIDATE_OVERLAY_BYTES` or remove that target from the overlay.
4. Ensure the overlay was generated against the same commit you are binding (don't add new files to the overlay without committing them first).

Example fix

# before: overlay references docs/NEW.md not yet committed
bases = committed_destination_base_digests(overlay)  # -> ValueError
# after: commit the file, then capture
import subprocess
subprocess.run(['git', 'add', 'docs/NEW.md'], cwd=repo_root, check=True)
subprocess.run(['git', 'commit', '-m', 'add docs/NEW.md'], cwd=repo_root, check=True)
bases = committed_destination_base_digests(overlay)

import subprocess
from workflow_bench.promotion_apply import candidate_overlay_payload, mirror_targets, MAX_CANDIDATE_OVERLAY_BYTES

def all_targets_exist_at_commit(repo_root, overlay, ref="HEAD") -> bool:
    _, payload = candidate_overlay_payload(overlay)
    targets = [t.as_posix() for rel, _ in payload for t in mirror_targets(rel)]
    for key in targets:
        r = subprocess.run(
            ["git", "-C", str(repo_root), "cat-file", "-e", f"{ref}:{key}"],
        )
        if r.returncode != 0:
            return False
    return True

null

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When it happens

Trigger: Calling `committed_destination_base_digests(overlay, ref=<ref>)` where the commit does not contain one of the overlay's target paths (`git show` exits non-zero), the file is larger than `MAX_CANDIDATE_OVERLAY_BYTES`, or `stdout_capture_overflow`/`None` capture made the result unusable.

Common situations: Overlay targets a file that was added in a later commit than `<ref>`; the path was renamed/removed before `<ref>`; the target path is in `.gitignore` and was never committed; the file is binary and exceeds the byte cap; the commit SHA resolved correctly but the path key has wrong casing or leading slash.

Related errors

• committed promotion base is not an immutable object id
• ${source}: branch name must not be empty.
• ${source}: branch name is too long (max ${BRANCH_MAX_LENGTH}
• ${source}: branch name must not contain whitespace.
• ${source}: branch name contains characters not allowed in a

AI-assisted analysis of abhigyanpatwari/GitNexus@d540b00184 (2026-08-12). Data as JSON: /api/errors/89b11b939f780e44. Report an issue: GitHub.