Fix profiler handling of synthetic positions

sjsonnet/src/sjsonnet/Profiler.scala

@@ -46,11 +46,12 @@ object ProfileOutputFormat {
  */
 final class Profiler(val format: ProfileOutputFormat, wd: Path) {
 
+  private def relativeFileName(pos: Position): Option[String] =
+    Option(pos).flatMap(p => Option(p.currentFile)).map(_.relativeToString(wd))
+
   private class ExprBox(val expr: Expr) {
     val id: BoxId = {
-      val fileName = Option(expr.pos)
-        .map(_.currentFile.relativeToString(wd))
-        .getOrElse("<unknown>")
+      val fileName = relativeFileName(expr.pos).getOrElse("<unknown>")
 
       val name = {
         val exprName = expr.getClass.getName.split('.').last.split('$').last
@@ -111,11 +112,8 @@ final class Profiler(val format: ProfileOutputFormat, wd: Path) {
 
   private def flameGraphFrameName(e: Expr): String = {
     val name = e.exprErrorString
-    if (isBuiltin(e) || e.pos == null) name
-    else {
-      val file = e.pos.currentFile.relativeToString(wd)
-      s"$name ($file)"
-    }
+    if (isBuiltin(e)) name
+    else relativeFileName(e.pos).fold(name)(file => s"$name ($file)")
   }
 
   private def getOrCreate(e: Expr): ExprBox = {

sjsonnet/test/src/sjsonnet/ProfilerTests.scala

@@ -0,0 +1,50 @@
+package sjsonnet
+
+import utest._
+
+object ProfilerTests extends TestSuite {
+  private val code =
+    """local f(x) = std.length(x) == std.length(std.objectFields({ a: 1, b: 2 }));
+      |f([1, 2])""".stripMargin
+
+  private def interpreter(): Interpreter =
+    new Interpreter(
+      Map.empty,
+      Map.empty,
+      DummyPath("root"),
+      Importer.empty,
+      parseCache = new DefaultParseCache
+    )
+
+  def tests: Tests = Tests {
+    test("synthetic static values have unknown source files") {
+      Seq(ProfileOutputFormat.Text, ProfileOutputFormat.FlameGraph).foreach { format =>
+        val interp = interpreter()
+        val profiler = new Profiler(format, DummyPath("root"))
+        interp.evaluator.profiler = profiler
+
+        interp.interpret(code, DummyPath("root", "main.jsonnet")) ==> Right(ujson.True)
+
+        val boxes = profiler.collectResult().boxes
+        assert(boxes.exists(_.id == BoxId("Num", "<unknown>", -1)))
+      }
+    }
+
+    test("flame graph frames can have synthetic positions") {
+      val pos = new Position(null, -1)
+      val frame = Expr.Apply1(
+        pos,
+        Expr.Id(pos, "f"),
+        Val.Null(pos),
+        tailstrict = false
+      )
+      val profiler = new Profiler(ProfileOutputFormat.FlameGraph, DummyPath("root"))
+
+      val saved = profiler.enter(frame)
+      profiler.exit(saved)
+
+      val boxes = profiler.collectResult().boxes
+      assert(boxes.exists(_.id.fileName == "<unknown>"))
+    }
+  }
+}