Aglet

Investigate upload chunk assembly with byte-level evidence

Investigation should model the complete byte sequence from request creation through receiver assembly. Use nonrepeating bytes and a file length that leaves a short final part, then compare every part record with the source. The brief should show whether the error begins before transmission or during assembly.

Build a useful investigation brief

  1. Build a diagnostic file

    Create a fixture whose bytes identify their position and whose length produces full chunks plus a remainder. Record the exact chunk size and expected ranges, including the empty-file and one-chunk cases if those paths differ.

  2. Trace parts and metadata

    For each request, record payload length, declared range, part number, response, and stored part location. Compare those records with the source slice and mark missing, duplicated, or reordered parts without treating equal lengths as proof of correctness.

  3. Locate the first divergence

    Reassemble the recorded parts independently and compare bytes and length with the source. Identify the earliest request or assembly operation that introduces a mismatch, then list competing explanations when the available trace cannot distinguish transport from receiver ordering.

What to carry forward

The investigation is sufficient when independent reconstruction identifies the first byte or metadata divergence. Stop at the earliest proven boundary and leave later symptoms as consequences, especially when a receiver accepts a malformed part before assembly.

Technical background: tus protocol documentation.

Keep the decision with the work.

Use a Work Item in Aglet to record the problem, the evidence you have, and the next decision. Add an owner and priority, then keep updates in the discussion so the next person can follow the reasoning.

Create an account See the product workflow