ALL-FUNC0009 · nesting_depth

Measure the deepest control nesting one callable reaches.

This is a deterministic rule for all languages. Read its implementation.

Definition

Read the nesting depth a provider recorded for every control structure inside one callable and return the deepest one. Depth counts the structures enclosing a structure rather than the structure itself, so the outermost loop of a body sits at depth zero and a condition written inside it sits at depth one. Depth is what forces a reader to hold earlier conditions in mind while reading the innermost statement, which is why it is measured on its own rather than folded into a single complexity number.

Evidence

Each finding records the callable range and the deepest structure with its own range. The value is that depth.

Exceptions

A callable with no resolved control structure has depth zero. Guard clauses that return early keep depth low by construction and are the usual repair, so the measurement rewards them without naming them.

Examples

A loop holding a condition holding a second condition returns 2, since the loop is at depth zero and the two conditions at depths one and two. The same logic written as three sequential guard clauses returns 0, because no structure encloses another. A callable with no control structure at all also returns 0.

References

• Generalizes Clippy excessive_nesting. Open reference
• Generalizes ESLint max-depth. Open reference
• Cites Pylint R1702 too-many-nested-blocks. Open reference