NESTING_INCREASED

Severity: warn (default) / error (new depth crosses the error threshold)

A POU's maximum control-structure nesting depth increased and now sits beyond the configured warn threshold. Depth counts nested IF / CASE / FOR / WHILE / REPEAT; the clauses of a construct (ELSIF, ELSE, each CASE arm) do not add depth on their own.

Why it matters. Deeply nested logic is where edge cases hide. A jump in nesting depth is an early signal that a POU is drifting toward arrow-shaped code that is hard to follow and easy to get wrong.

Settings. Reads metrics.thresholds.nesting_depth from .plc-st-review.yml:

metrics:
  thresholds:
    nesting_depth:
      warn: 5
      error: 8

Fires only when the new depth exceeds the warn band. Escalates to error when the new depth reaches the error band and the old value was below it.

Trigger.

(* before: max nesting 5 *)
(* after: a new inner FOR inside the deepest IF takes it to 6 *)

The bot posts.

🟧 warn  NESTING_INCREASED
FB_RecipeHandler max nesting depth: 5 → 6 (warn threshold 5)

Fix. Flatten with guard clauses (early RETURN/CONTINUE), invert conditions, or hoist an inner block into its own method.