Documentation · Chapter 19

Diagnose from evidence instead of trying random fixes.

Troubleshooting is the disciplined reduction of possible causes. Preserve the first error, reproduce the smallest case, inspect the responsible boundary, change one thing, then verify.

Every lesson starts from the problem, explains the mechanism, then gives a concrete verification.

≈ 75 min

Capture before changing

Record exact command, working directory, full message, time, versions, URL, status, and the first relevant log line before clearing the screen.

LESSON OBJECTIVE

What you will be able to do

Preserve the first failure evidence and reduce the set of possible causes before changing anything.

Minimize the reproduction

Remove unrelated features until the failure remains. A minimal route, query, or component reveals ownership faster than editing several packages.

Confirm the correction

Repeat the original scenario and a nearby negative scenario. Add a test or diagnostic so the same defect becomes easier to identify.

CHECKPOINT

Before you continue

Did you record the original message, directory, versions, status, and first log evidence before clearing or reinstalling?