Skip to content

Build Lints

mur build checks the file set it is about to pack before it writes a byte of zip. What it finds is reported two ways:

  • E-BLD-NNN errors stop the build. No .mur.zip is written — not a partial one, not an empty one.
  • W-BLD-NNN warnings go to stderr and the build completes. They flag a packaging mistake that still produces a working artifact.

Both classes are about packaging: what ends up inside the archive, and whether the runtime will be able to launch it. They are distinct from the W-SEC-NNN warnings, which are about capability and enforcement posture.

Code Kind Summary
E-BLD-001 error name: is not a valid artifact identifier
E-BLD-002 error A requires_files: entry is unsafe or collides inside the archive
E-BLD-003 error The packed entry set is not a launchable wasm payload
W-BLD-001 warning A declaration names an archive entry the packer already fills
W-BLD-002 warning capsule.wasm shadows another root *.wasm
W-BLD-003 warning A compiled artifact packages build inputs

E-BLD-001

invalid artifact name '<name>': <reason>

An artifact name: becomes a filename (<name>-<version>.mur.zip), a registry key and a directory in the local store, so it is held to the lowest common denominator of all three:

  • non-empty, at most 100 characters
  • ASCII lowercase letters, digits and - only
  • no leading or trailing -

Uppercase letters, spaces, /, \ and _ are rejected by the character rule. This is a format check only — it reserves no prefix and no namespace. murmur-hook-compact and murmur-tool-git are ordinary valid names; who may publish a given name is a registry question, not a packaging one.

name: my-tool        # ok
name: My Tool        # E-BLD-001
name: my_tool        # E-BLD-001
name: -my-tool       # E-BLD-001

E-BLD-002

requires_files entry '<entry>' has an unsafe path: <reason> requires_files entry '<entry>' is a symlink (<path>); declare the file it points to instead requires_files entries '<a>' and '<b>' both pack as the archive entry '<name>'

Every requires_files: entry must be a plain relative path to a real file inside the source directory, and the entries must not collide once they are inside the archive:

  • No absolute paths. /etc/hosts joined onto the source directory is /etc/hosts.
  • No .. components. This is the same rule any .mur.zip reader applies to an entry name it unpacks (see sanitize_entry_path), applied at authoring time.
  • No symlinks. The link is not followed: packing it would ship whatever it resolves to — plausibly from outside the source tree — under the declared name.
  • No two declarations claiming one archive entry. The archive name is a rewrite of the declared path (\ → /), so two distinct files can otherwise land in the same slot, where one silently overwrites the other on unpack.

A requires_files: entry that redundantly names murmur.yaml is not a collision — it is dropped before packing, and reported as W-BLD-001 instead.

E-BLD-003

missing root .wasm file (expected capsule.wasm or one root *.wasm) multiple root .wasm files found: <names>

The artifact's runtime:/execution: resolve to a wasm artifact, but the entry set about to be packed does not contain exactly one payload the runtime could select. mur build never compiles anything, so a .wasm must already exist on disk and be declared in requires_files:.

The rule is the runtime's own payload-selection rule, and the message is the runtime's message verbatim — a build that passes this check cannot fail payload selection at mur run time:

  • exactly one root *.wasm entry → selected
  • a root capsule.wasm → always selected, however many other root *.wasm entries exist (which is why that case is a warning, not an error — see W-BLD-002)
  • zero root *.wasm entries → missing root .wasm file
  • two or more, none named capsule.wasm → multiple root .wasm files found

A *.wasm in a subdirectory is not a root entry and does not count. This check applies only to wasm artifacts — native (implementation: native) and static (runtime: skill, execution: static) artifacts are packed without it.

W-BLD-001

requires_files entry '<entry>' names the reserved archive entry '<name>', which mur build already packs

Two root entries have a fixed meaning inside a .mur.zip: murmur.yaml is seeded by the packer itself, and capsule.wasm is the payload the runtime prefers over every other root *.wasm. Declaring murmur.yaml in requires_files: packs nothing extra — the entry is deduplicated away and the artifact is byte-identical without it.

Remove the declaration.

W-BLD-002

root 'capsule.wasm' is always selected as the payload, so <names> ships but never runs

The artifact carries a root capsule.wasm and at least one other root *.wasm. The build succeeds — capsule.wasm makes payload selection unambiguous — but the other file is shipped and never executed.

Keep exactly one root *.wasm: drop capsule.wasm, or rename the payload you meant to run.

W-BLD-003

compiled artifact packages build inputs: <names>

A wasm or native artifact declares an obvious build input in requires_files: — Cargo.toml, Cargo.lock, a *.rs file, or anything under a target/ path. A compiled artifact ships its payload, not the sources it was built from, so this is almost always a stray declaration.

Static artifacts (runtime: skill) are exempt: their files are their content.