Test that we can link twice on the same linker with GCC

gzm0 · gzm0 · commit 3572a4b53b20 · 2024-01-02T14:31:00.000+01:00
Ensures that we catch issues like this: scala-js#4917 (comment)
diff --git a/linker/jvm/src/test/scala/org/scalajs/linker/GCCLinkerTest.scala b/linker/jvm/src/test/scala/org/scalajs/linker/GCCLinkerTest.scala
@@ -16,9 +16,13 @@ import org.junit.Test
 
 import org.scalajs.junit.async._
 
+import org.scalajs.logging._
+
 import org.scalajs.linker.interface.StandardConfig
 
+import org.scalajs.linker.testutils.{MemClassDefIRFile, TestIRRepo}
 import org.scalajs.linker.testutils.LinkingUtils._
+import org.scalajs.linker.testutils.TestIRBuilder._
 
 class GCCLinkerTest {
   import scala.concurrent.ExecutionContext.Implicits.global
@@ -30,4 +34,30 @@ class GCCLinkerTest {
      */
     testLink(Nil, Nil, config = StandardConfig().withClosureCompiler(true))
   }
+
+  @Test
+  def linkIncrementalSmoke(): AsyncResult = await {
+    /* Check that linking twice works. GCC trees are highly mutable, so if we
+     * (re-)use them wrongly over multiple runs, things can fail unexpectedly.
+     *
+     * We change something about the code in the second run to force the linker
+     * to actually re-run.
+     */
+    def classDef(text: String) =
+      MemClassDefIRFile(mainTestClassDef(consoleLog(str(text))))
+
+    val moduleInitializers = MainTestModuleInitializers
+
+    val config = StandardConfig().withCheckIR(true).withClosureCompiler(true)
+    val linker = StandardImpl.linker(config)
+
+    val output = MemOutputDirectory()
+    val logger = new ScalaConsoleLogger(Level.Error)
+
+    for {
+      lib <- TestIRRepo.minilib
+      _ <- linker.link(lib :+ classDef("test 1"), moduleInitializers, output, logger)
+      _ <- linker.link(lib :+ classDef("test 2"), moduleInitializers, output, logger)
+    } yield ()
+  }
 }
