Bug 1548469 - Step in to the next script r=jlast

Depends on D65008

Differential Revision: https://phabricator.services.mozilla.com/D65009

--HG--
extra : moz-landing-system : lando

devtools/server/actors/thread.js

@@ -840,6 +840,7 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
 
       frame.onStep = onStep;
       frame.onPop = onPop;
+      frame.waitingOnStep = true;
       return undefined;
     };
   },
@@ -1025,19 +1026,25 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
       steppingType = "next";
     }
 
+    // If there are no more frames on the stack, use "step" mode so that we will
+    // pause on the next script to execute.
+    const stepFrame = this._getNextStepFrame(frame);
+    if (!stepFrame) {
+      steppingType = "step";
+    }
+
     const { onEnterFrame, onPop, onStep } = this._makeSteppingHooks({
       steppingType,
       completion,
     });
 
-    // Make sure there is still a frame on the stack if we are to continue
+    if (steppingType === "step") {
-    // stepping.
+      this.dbg.onEnterFrame = onEnterFrame;
-    const stepFrame = this._getNextStepFrame(frame);
+    }
+
     if (stepFrame) {
       switch (steppingType) {
         case "step":
-          this.dbg.onEnterFrame = onEnterFrame;
-        // Fall through.
         case "break":
         case "next":
           if (stepFrame.script) {

devtools/server/tests/xpcshell/test_stepping-17.js

@@ -0,0 +1,75 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/*
+ * Check that you can step from one script or event to another
+ */
+
+add_task(
+  threadFrontTest(async ({ threadFront, targetFront, debuggee }) => {
+    const consoleFront = await targetFront.getFront("console");
+
+    Cu.evalInSandbox(
+      `function blackboxed(callback) { return () => callback(); }`,
+      debuggee,
+      "1.8",
+      "http://example.com/blackboxed.js",
+      1
+    );
+
+    const { sources } = await getSources(threadFront);
+    const blackboxedSourceFront = threadFront.source(
+      sources.find(source => source.url == "http://example.com/blackboxed.js")
+    );
+    blackBox(blackboxedSourceFront);
+
+    const testStepping = async function(wrapperName, stepHandler, message) {
+      consoleFront.evaluateJSAsync(
+        `(function () {
+          const p = Promise.resolve();
+          p.then(${wrapperName}(() => { debugger; }))
+          .then(${wrapperName}(() => { }));
+        })();`
+      );
+
+      await waitForEvent(threadFront, "paused");
+      const step = await stepHandler(threadFront);
+      Assert.equal(step.frame.where.line, 4, message);
+      await resume(threadFront);
+    };
+
+    const stepTwice = async function() {
+      await stepOver(threadFront);
+      return stepOver(threadFront);
+    };
+
+    await testStepping("", stepTwice, "Step over on the outermost frame");
+    await testStepping("blackboxed", stepTwice, "Step over with blackboxing");
+    await testStepping("", stepOut, "Step out on the outermost frame");
+    await testStepping("blackboxed", stepOut, "Step out with blackboxing");
+
+    consoleFront.evaluateJSAsync(
+      `(async function () {
+        const p = Promise.resolve();
+        const p2 = p.then(() => {
+          debugger;
+          return "async stepping!";
+        });
+        debugger;
+        await p;
+        const result = await p2;
+        return result;
+      })();
+      `
+    );
+
+    await waitForEvent(threadFront, "paused");
+    await stepOver(threadFront);
+    await stepOver(threadFront);
+    const step = await stepOut(threadFront);
+    await resume(threadFront);
+    Assert.equal(step.frame.where.line, 9, "Step out of promise into async fn");
+  })
+);

devtools/server/tests/xpcshell/xpcshell.ini

@@ -183,6 +183,7 @@ skip-if = true # breakpoint sliding is not supported bug 1525685
 [test_stepping-14.js]
 [test_stepping-15.js]
 [test_stepping-16.js]
+[test_stepping-17.js]
 [test_stepping-with-skip-breakpoints.js]
 [test_framebindings-01.js]
 [test_framebindings-02.js]