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unreachable-after-break

Category: Unreachable Code
Severity: Critical
Triggered by: pyscn analyze, pyscn check

What it does

Flags statements that appear after a break statement inside a loop.

Why is this a problem?

break exits the enclosing loop immediately. Anything after it in the same block runs zero times.

Common causes:

  • A misplaced increment or accumulator update — the author intended it to run on the final iteration.
  • Leftover logging or cleanup — moved below the break during a refactor.
  • Confused control flow — the author expected break to skip only part of the iteration.

The code is unreachable, so tests cannot cover it and bugs inside it will never surface.

Example

for user in users:
    if user.id == target_id:
        break
        user.last_seen = now()   # ← never executes

Use instead

Perform the work before the break, or remove the dead statement.

for user in users:
    if user.id == target_id:
        user.last_seen = now()
        break

Options

Option Default Description
dead_code.detect_after_break true Set to false to disable this rule.
dead_code.min_severity "warning" "critical" keeps only this kind of finding; "info" surfaces more.
dead_code.ignore_patterns [] Regex patterns matched against the source line; matches are suppressed.

References