Kaldi data directory validation warning policy for wav.scp and utt2spk

Direct Answer

By default, utils/validate_data.sh treats missing entries in wav.scp or utt2spk as warnings only and exits successfully. The script does not promote these warnings to fatal errors in any upstream Kaldi release. Whether training or decoding halts is entirely determined by the recipe or operator.

The permission boundary that separates validation from pipeline execution should be an explicit CI gate that runs validation as a separate step, fails on any warning output (not just exit code), and blocks downstream stages until the data directory passes cleanly.

Confirmed Behavior

• validate_data.sh checks wav.scp, utt2spk, and text consistency; missing audio files and utterance-ID mismatches are reported as warnings.
• The script typically returns exit code 0 even when warnings are printed, so echo $? alone cannot gate the pipeline.
• utils/fix_data_dir.sh repairs sorting and some inconsistencies but does not change the warning policy.
• Decoding directories often omit text, so text-related checks are skipped while wav.scp/utt2spk checks still apply.

Reproducible Workflow Pattern

1. Run validation as an independent step before feature extraction or training:

   utils/validate_data.sh data/train 2>&1 | tee validate.log
   if [ ${PIPESTATUS[0]} -ne 0 ] || grep -q "WARNING" validate.log; then
     echo "Validation failed" >&2; exit 1
   fi

2. Do not manually edit wav.scp or utt2spk after validation without re-running the gate.
3. Encode this gate in your recipe's run.sh or CI configuration so it cannot be bypassed.

Version Sensitivity

Script options and defaults differ across Kaldi releases and local forks. Some downstream containers or recipe wrappers replace validate_data.sh entirely. The only reliable way to know your installation's behavior is to test it.

One Diagnostic Detail Needed

What is the exact Kaldi source (upstream commit hash, fork name, or container image tag) you are using? This determines whether any --strict or --warnings-as-errors flag exists and whether the exit code already fails on warnings.