Swift: Improve regex performance with possessive matching (i.e. don't backtrack).

geoffw0 · geoffw0 · commit deb97a6ccc14 · 2023-08-03T13:57:49.000+01:00
diff --git a/swift/ql/lib/codeql/swift/elements/type/Type.qll b/swift/ql/lib/codeql/swift/elements/type/Type.qll
@@ -15,7 +15,7 @@ class Type extends Generated::Type {
     // replace anything that looks like a full name `a.b.c` with just the
     // short name `c`, by removing the `a.` and `b.` parts. Note that this
     // has to be robust for tuple type names such as `(a, b.c)`.
-    result = super.getName().regexpReplaceAll("[^(),. ]+\\.(?!\\.)", "")
+    result = super.getName().regexpReplaceAll("[^(),. ]++\\.(?!\\.)", "")
   }
 
   /**

Original file line number	Diff line number	Diff line change
`@@ -15,7 +15,7 @@ class Type extends Generated::Type {`
`15`	`15`	// replace anything that looks like a full name `a.b.c` with just the
`16`	`16`	// short name `c`, by removing the `a.` and `b.` parts. Note that this
`17`	`17`	// has to be robust for tuple type names such as `(a, b.c)`.
`18`		`- result = super.getName().regexpReplaceAll("[^(),. ]+\\.(?!\\.)", "")`
	`18`	`+ result = super.getName().regexpReplaceAll("[^(),. ]++\\.(?!\\.)", "")`
`19`	`19`	`}`
`20`	`20`
`21`	`21`	`/**`