Expose & Add unit tests

internal/compiler-interface/src/main/java/xsbti/CompileFailed2.java

@@ -16,9 +16,7 @@
 public abstract class CompileFailed2 extends CompileFailed {
     /**
      * Returns SourceInfos containing problems for each file.
-     * This includes problems found by most recent compilation run and by all prior compilation runs.
-     * This does not include problems found by prior compilation runs that are no longer valid.
-     * e.g. If A.scala previously has a problem, but no longer has a problem, it will not be included.
+     * This includes problems found by most recent compilation run.
      */
     public abstract ReadSourceInfos sourceInfos();
 }

internal/zinc-compile-core/src/main/scala/sbt/internal/inc/RawCompiler.scala

@@ -15,6 +15,7 @@ package inc
 
 import java.nio.file.Path
 import sbt.internal.util.FeedbackProvidedException
+import xsbti.compile.analysis.ReadSourceInfos
 import xsbti.compile.{ ClasspathOptions, ScalaInstance => XScalaInstance }
 
 /**
@@ -98,11 +99,12 @@ class CompileFailed(
     val arguments: Array[String],
     override val toString: String,
     val problems: Array[xsbti.Problem],
+    val sourceInfosOption: Option[ReadSourceInfos],
     cause: Throwable
 ) extends xsbti.CompileFailed(cause)
     with FeedbackProvidedException {
 
   def this(arguments: Array[String], toString: String, problems: Array[xsbti.Problem]) = {
-    this(arguments, toString, problems, null)
+    this(arguments, toString, problems, None, null)
   }
 }

zinc/src/main/scala/sbt/internal/inc/IncrementalCompilerImpl.scala

@@ -331,11 +331,19 @@ class IncrementalCompilerImpl extends IncrementalCompiler {
     try {
       compilerRun
     } catch {
+      case e: xsbti.CompileFailed2 => throw new sbt.internal.inc.CompileFailed(
+          e.arguments,
+          e.toString,
+          e.problems,
+          Some(e.sourceInfos()),
+          e,
+        ) // just ignore
       case e: xsbti.CompileFailed =>
         throw new sbt.internal.inc.CompileFailed(
           e.arguments,
           e.toString,
           e.problems,
+          None,
           e
         ) // just ignore
       case e: CompileFailed        => throw e // just ignore

zinc/src/test/scala/sbt/inc/IncrementalCompilerSpec.scala

@@ -240,4 +240,25 @@ class IncrementalCompilerSpec extends BaseCompilerSpec {
         }
       } finally comp.close()
   }
+
+  it should "emit SourceInfos when incremental compilation fails" in withTmpDir {
+    tmp =>
+      val project = VirtualSubproject(tmp.toPath / "p1")
+      val comp = project.setup.createCompiler()
+      val s1 = "object A { final val i = 1"
+      val f1 = StringVirtualFile("A.scala", s1)
+      try {
+        val exception = intercept[CompileFailed] {
+          comp.compile(f1)
+        }
+        exception.sourceInfosOption match {
+          case Some(sourceInfos) =>
+            assert(
+              !sourceInfos.getAllSourceInfos.isEmpty,
+              "Expected non-empty source infos"
+            )
+          case None => fail("Expected sourceInfos")
+        }
+      } finally comp.close()
+  }
 }