From 5223adb474d755e1db50a79322e169388e44222c Mon Sep 17 00:00:00 2001
From: Kacper Korban <kacper.f.korban@gmail.com>
Date: Sun, 25 Feb 2024 22:15:48 +0100
Subject: [PATCH] Pre compute coverage filter patterns

---
 .../dotc/transform/InstrumentCoverage.scala    | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/transform/InstrumentCoverage.scala b/compiler/src/dotty/tools/dotc/transform/InstrumentCoverage.scala
index aa3b48e53f35..a39a1c6f591e 100644
--- a/compiler/src/dotty/tools/dotc/transform/InstrumentCoverage.scala
+++ b/compiler/src/dotty/tools/dotc/transform/InstrumentCoverage.scala
@@ -21,6 +21,7 @@ import util.Spans.Span
 import localopt.StringInterpolatorOpt
 import inlines.Inlines
 import scala.util.matching.Regex
+import java.util.regex.Pattern
 
 /** Implements code coverage by inserting calls to scala.runtime.coverage.Invoker
   * ("instruments" the source code).
@@ -43,6 +44,9 @@ class InstrumentCoverage extends MacroTransform with IdentityDenotTransformer:
   // stores all instrumented statements
   private val coverage = Coverage()
 
+  private var coverageExcludeClasslikePatterns: List[Pattern] = Nil
+  private var coverageExcludeFilePatterns: List[Pattern] = Nil
+
   override def run(using ctx: Context): Unit =
     val outputPath = ctx.settings.coverageOutputDir.value
 
@@ -56,19 +60,21 @@ class InstrumentCoverage extends MacroTransform with IdentityDenotTransformer:
         .filter(_.nn.getName.nn.startsWith("scoverage"))
         .foreach(_.nn.delete())
     end if
+
+    coverageExcludeClasslikePatterns = ctx.settings.coverageExcludeClasslikes.value.map(_.r.pattern)
+    coverageExcludeFilePatterns = ctx.settings.coverageExcludeFiles.value.map(_.r.pattern)
+
     super.run
 
     Serializer.serialize(coverage, outputPath, ctx.settings.sourceroot.value)
 
   private def isClassIncluded(sym: Symbol)(using Context): Boolean =
-    val excludedClassNamePatterns = ctx.settings.coverageExcludeClasslikes.value.map(_.r.pattern)
-    excludedClassNamePatterns.isEmpty || !excludedClassNamePatterns.exists(
+    coverageExcludeClasslikePatterns.isEmpty || !coverageExcludeClasslikePatterns.exists(
       _.matcher(sym.fullName.toText(ctx.printerFn(ctx)).show).nn.matches
     )
 
   private def isFileIncluded(file: SourceFile)(using Context): Boolean =
-    val excludedFilePatterns = ctx.settings.coverageExcludeFiles.value.map(_.r.pattern)
-    excludedFilePatterns.isEmpty || !excludedFilePatterns.exists(
+    coverageExcludeFilePatterns.isEmpty || !coverageExcludeFilePatterns.exists(
       _.matcher(file.path.replace(".scala", "")).nn.matches
     )
 
@@ -283,14 +289,14 @@ class InstrumentCoverage extends MacroTransform with IdentityDenotTransformer:
             transformDefDef(tree)
 
           case tree: PackageDef =>
-            if (isFileIncluded(tree.srcPos.sourcePos.source) && isClassIncluded(tree.symbol))
+            if isFileIncluded(tree.srcPos.sourcePos.source) && isClassIncluded(tree.symbol) then
               // only transform the statements of the package
               cpy.PackageDef(tree)(tree.pid, transform(tree.stats))
             else
               tree
 
           case tree: TypeDef =>
-            if (isFileIncluded(tree.srcPos.sourcePos.source) && isClassIncluded(tree.symbol))
+            if isFileIncluded(tree.srcPos.sourcePos.source) && isClassIncluded(tree.symbol) then
               super.transform(tree)
             else
               tree