Optimize baseline filtering (#912)

Author: ileitch

CHANGELOG.md

@@ -12,6 +12,7 @@
 
 - Fix unused import false-positives where the only referenced declaration is generated by a macro.
 - Fix building with Bazel on Linux by excluding Xcode support.
+- Fix slow baseline filtering for large projects with many results.
 
 ## 3.1.0 (2025-04-05)
 

Sources/PeripheryKit/Results/OutputDeclarationFilter.swift

@@ -20,12 +20,16 @@ public final class OutputDeclarationFilter {
 
         if let baseline {
             var didFilterDeclaration = false
+            let ignoredUsrs = declarations
+                .flatMapSet(\.usrs)
+                .intersection(baseline.usrs)
+
             declarations = declarations.filter {
-                let isDisjoint = $0.usrs.isDisjoint(with: baseline.usrs)
-                if !isDisjoint {
+                let isIgnored = $0.usrs.contains { ignoredUsrs.contains($0) }
+                if isIgnored {
                     didFilterDeclaration = true
                 }
-                return isDisjoint
+                return !isIgnored
             }
 
             if !didFilterDeclaration {