denoland/deno · error

invalid module type

Error message

invalid module type

What it means

In the same parse loop, after resolving a source offset to a specifier, the module must be EszipV2Module::Module to receive source bytes; hitting the catch-all arm panics "invalid module type". Well-formed writers never emit source byte sections for Redirect entries (redirects have no source), so this means the archive's sources section references a redirect module — a structural inconsistency only a corrupted or mis-generated file can contain.

Source

Thrown at libs/eszip/v2.rs:964

        let wakers = {
          let mut modules = modules.lock().unwrap();
          let module = modules.get_mut(&specifier).expect("module not found");
          match module {
            EszipV2Module::Module { source, .. } => {
              let slot = std::mem::replace(
                source,
                EszipV2SourceSlot::Ready(Arc::from(
                  source_bytes.into_content(),
                )),
              );

              match slot {
                EszipV2SourceSlot::Pending { wakers, .. } => wakers,
                _ => panic!("already populated source slot"),
              }
            }
            _ => panic!("invalid module type"),
          }
        };
        for w in wakers {
          w.wake();
        }
      }

      let source_maps_len = read_u32(&mut reader).await? as usize;
      let mut read = 0;

      while read < source_maps_len {
        let (length, specifier) = source_map_offsets
          .remove(&read)
          .ok_or(ParseError::InvalidV2SourceOffset(read))?;

        let source_map_bytes =
          Section::read_with_size(&mut reader, options, length).await?;
        if !source_map_bytes.is_checksum_valid() {

View on GitHub (pinned to 9ad36f7a2c)

Solutions

1. Rebuild the artifact with a current, unmodified toolchain
2. Verify transport integrity (checksums, re-download) before parsing
3. Isolate the failure with EszipV2::parse on the raw bytes to rule out upstream I/O corruption
4. Capture the artifact and report the structural bug to the eszip maintainers

// Same pre-flight: confirm magic and integrity metadata before parse.
assert!(EszipV2::has_magic(&bytes[..8]), "not an eszip v2 artifact");

When it happens

Trigger: Parsing an eszip v2 whose sources section contains an entry whose specifier maps to a Redirect module; files written by buggy or incompatible custom eszip producers; corruption that shifts offsets so source bytes are attributed to the wrong specifier.

Common situations: Compiled artifacts transferred without integrity checks; eszips produced by patched/forked tooling; cross-version artifact processing pipelines.

Related errors

• redirects are already resolved
• Redirects should be resolved
• missing index '{}'
• invalid utf-8 data
• Unable to parse body as form data

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/beea01a4061e4108. Report an issue: GitHub.