Deep nesting

Code longer than it needs to be: one of the ways AI coding agents bloat software, from lessloc's pattern catalog. lessloc catches it as deep-nesting.

What makes deep nesting a bad practice?

The standards that call it a bad practice: CWE-1124 Excessively Deep Nesting; Sonar S134; Fowler: Replace Nested Conditional with Guard Clauses.

What does lessloc do about deep nesting?

lessloc catches it as deep-nesting.

• deep-nesting (tier 2): Statements nested 4 or more control levels deep.

Examples

Caught as deep-nesting:

def scan(rows):
    for r in rows:
        if r:
            for c in r:
                if c:
                    print(c)

Written well:

def scan(rows):
    for r in rows:
        for c in r or []:
            if c:
                print(c)

Related patterns

The other patterns in Code longer than it needs to be:

• Brute-force idioms: lessloc catches it as simpler, built in for Python, JS/TS, Go, Rust, Java and C#. ruff (in every hook) and clippy (in ci) go deeper.
• Hand-built counters and flag loops: lessloc catches it as simpler.
• A catch that only rethrows: lessloc catches it as simpler.
• A promise wrapped in new Promise: lessloc catches it as simpler.
• Annotating types the compiler infers: lessloc catches it as simpler.
• A React Effect that only sets state from other values: lessloc catches it as simpler.
• Functions with many parameters (8 or more): lessloc catches it as long-params.
• Long functions: lessloc catches it as long-function.
• If-chains on literal values: lessloc catches it as if-chain.
• A file that keeps growing: lessloc catches it as swollen-file.
• Reformatting lines the task did not change: lessloc gives every session a rule against it and catches it as churn.
• Net growth past a budget: lessloc catches it as net-growth.
• Golfed code: lessloc catches it as clever and dense-lines.