rust-lang/rust · critical · Exception

Unable to parse transfer manifest

Error message

Unable to parse transfer manifest

What it means

Raised by TestEnvironment.start() when json.loads(output) or the subsequent ['transfer_manifest_url'] access on ffx's 'product lookup' JSON output fails. The runner looks up the product bundle transfer manifest URL from ffx to download the emulator image; any parsing/key failure is fatal because there is no URL to download. The original exception is chained via 'raise ... from e'.

Source

Thrown at src/ci/docker/scripts/fuchsia-test-runner.py:525

                    "--machine",
                    "json",
                    "product",
                    "lookup",
                    product_name,
                    sdk_version,
                    "--base-url",
                    "gs://fuchsia/development/" + sdk_version,
                ],
                env=ffx_env,
                stdout_handler=self.subprocess_logger.debug,
                stderr_handler=self.subprocess_logger.debug,
            )

            try:
                transfer_manifest_url = json.loads(output)["transfer_manifest_url"]
            except Exception as e:
                print(e)
                raise Exception("Unable to parse transfer manifest") from e

            # Download the product bundle.
            self.env_logger.info("Downloading the product bundle...")
            check_call_with_logging(
                [
                    ffx_path,
                    "product",
                    "download",
                    transfer_manifest_url,
                    self.local_pb_path,
                ],
                env=ffx_env,
                stdout_handler=self.subprocess_logger.debug,
                stderr_handler=self.subprocess_logger.debug,
            )

        # Start emulator
        self.env_logger.info("Starting emulator...")

View on GitHub (pinned to 7088e4b63a)

Solutions

1. Run the exact ffx command manually to see the raw output: `ffx --machine json product lookup minimal.{arch} {sdk_version} --base-url gs://fuchsia/development/{sdk_version}` and inspect the JSON.
2. Confirm the SDK version (read from {sdk_dir}/meta/manifest.json 'id') actually exists in the gs://fuchsia/development catalog.
3. Authenticate ffx / ensure network and GCS access, then retry 'start'.
4. Use --use-local-product-bundle-if-exists with a pre-downloaded bundle to bypass the lookup entirely.
5. Update fuchsia-test-runner.py to match a newer ffx output schema if the key was renamed.

Example fix

// before
$ fuchsia-test-runner.py start --sdk ... --target aarch64-unknown-fuchsia ...
# Exception: Unable to parse transfer manifest

// after - reproduce the ffx call to see the real error
$ ffx --machine json product lookup minimal.arm64 <sdk_id> --base-url gs://fuchsia/development/<sdk_id>
# fix auth / network / version, then re-run start

import json, subprocess

out = subprocess.run(
    [ffx_path, "--machine", "json", "product", "lookup", product_name, sdk_version,
     "--base-url", f"gs://fuchsia/development/{sdk_version}"],
    stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=ffx_env,
).stdout
try:
    url = json.loads(out)["transfer_manifest_url"]
except Exception:
    raise SystemExit(f"ffx product lookup did not return a transfer_manifest_url; raw output:\n{out!r}")

def has_transfer_manifest_url(payload) -> bool:
    return isinstance(payload, dict) and isinstance(payload.get("transfer_manifest_url"), str)

try:
    test_env.start()
except Exception as e:
    if "Unable to parse transfer manifest" in str(e):
        logging.error("ffx product lookup failed; check SDK version, network, and ffx auth.")
    raise

When it happens

Trigger: Reached at fuchsia-test-runner.py:521-525 during 'start' when use_local_pb is false or the local product bundle path does not exist. ffx product lookup returned output that is not JSON, or JSON missing the 'transfer_manifest_url' key (e.g. an error payload, empty output, or a schema change in a newer ffx).

Common situations: SDK/ffx version mismatch (ffx returns an error object instead of a lookup result); no network access so ffx emitted a connection error to stdout; product name / SDK version do not exist in the catalog; ffx authentication to the storage backend failed; ffx output schema changed between SDK releases.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Unrecognized target triple {triple}
• llvm-readelf failed for binary {binary} with output {stdout}
• Build ID not found for binary {binary}
• Unrecognized host architecture {machine}
• Temp directory is not clean (in {tmp_dir})

AI-assisted analysis of rust-lang/rust@7088e4b63a (2026-08-10). Data as JSON: /api/errors/88ce9107d1562f93. Report an issue: GitHub.