Is Disjoint
ID |
swift.is_disjoint |
Severity |
info |
Remediation Complexity |
trivial |
Remediation Risk |
low |
Remediation Effort |
low |
Resource |
Efficiency |
Language |
Swift |
Tags |
efficiency, idiomatic |
Description
Reports a .intersection(other).isEmpty chain. The standard
library exposes isDisjoint(with:) for the same predicate without
materialising the intersection set.
a.intersection(b).isEmpty // FLAW
a.isDisjoint(with: b) // OKRationale
.intersection(b) allocates a new set and walks both inputs to
completion before .isEmpty is even evaluated.
.isDisjoint(with:) walks the smaller set once and stops at the
first shared element. On large sets the difference is measurable;
even on tiny sets, isDisjoint(with:) is the idiomatic spelling.
Remediation
Replace the chain with isDisjoint(with:):
if a.isDisjoint(with: b) { ... }If you need the intersection itself elsewhere, keep the call but store the result instead of just checking emptiness.