[release/6.0] [wasm][debugger] Fixing error after receiving loaded_files = null (#63739)

* Backporting #63591

* Fix merge error.

* Fixing html page.

Author: thaystg

src/mono/wasm/debugger/BrowserDebugProxy/MonoProxy.cs

@@ -1185,18 +1185,18 @@ internal async Task<DebugStore> LoadStore(SessionId sessionId, CancellationToken
 
             try
             {
-                string[] loaded_files = context.LoadedFiles;
+                string[] loaded_files = await GetLoadedFiles(sessionId, context, token);
 
                 if (loaded_files == null)
                 {
-                    Result loaded = await SendMonoCommand(sessionId, MonoCommands.GetLoadedFiles(), token);
-                    loaded_files = loaded.Value?["result"]?["value"]?.ToObject<string[]>();
+                    Console.WriteLine($"Failed to get the list of loaded files. Managed code debugging won't work due to this.");
                 }
-
-                await
-                foreach (SourceFile source in context.store.Load(sessionId, loaded_files, token).WithCancellation(token))
+                else
                 {
-                    await OnSourceFileAdded(sessionId, source, context, token);
+                    await foreach (SourceFile source in context.store.Load(sessionId, loaded_files, token).WithCancellation(token))
+                    {
+                        await OnSourceFileAdded(sessionId, source, context, token);
+                    }
                 }
             }
             catch (Exception e)
@@ -1207,6 +1207,25 @@ internal async Task<DebugStore> LoadStore(SessionId sessionId, CancellationToken
             if (!context.Source.Task.IsCompleted)
                 context.Source.SetResult(context.store);
             return context.store;
+
+            async Task<string[]> GetLoadedFiles(SessionId sessionId, ExecutionContext context, CancellationToken token)
+            {
+                if (context.LoadedFiles != null)
+                    return context.LoadedFiles;
+
+                Result loaded = await SendMonoCommand(sessionId, MonoCommands.GetLoadedFiles(), token);
+                if (!loaded.IsOk)
+                {
+                    Console.WriteLine($"Error on mono_wasm_get_loaded_files {loaded}");
+                    return null;
+                }
+
+                string[] files = loaded.Value?["result"]?["value"]?.ToObject<string[]>();
+                if (files == null)
+                    Console.WriteLine($"Error extracting the list of loaded_files from the result of mono_wasm_get_loaded_files: {loaded}");
+
+                return files;
+            }
         }
 
         private async Task<DebugStore> RuntimeReady(SessionId sessionId, CancellationToken token)

src/mono/wasm/debugger/DebuggerTestSuite/BreakpointTests.cs

@@ -642,5 +642,75 @@ await EvaluateAndCheck(
                 }
             );
         }
+
+        [Fact]
+        public async Task CreateGoodBreakpointAndHitGoToWasmPageWithoutAssetsComeBackAndHitAgain()
+        {
+            var bp = await SetBreakpoint("dotnet://debugger-test.dll/debugger-test.cs", 10, 8);
+            var pause_location = await EvaluateAndCheck(
+                "window.setTimeout(function() { invoke_add(); }, 1);",
+                "dotnet://debugger-test.dll/debugger-test.cs", 10, 8,
+                "IntAdd");
+            Assert.Equal("other", pause_location["reason"]?.Value<string>());
+            Assert.Equal(bp.Value["breakpointId"]?.ToString(), pause_location["hitBreakpoints"]?[0]?.Value<string>());
+
+            var top_frame = pause_location["callFrames"][0];
+            Assert.Equal("IntAdd", top_frame["functionName"].Value<string>());
+            Assert.Contains("debugger-test.cs", top_frame["url"].Value<string>());
+
+            CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 8, 4, scripts, top_frame["functionLocation"]);
+
+            //now check the scope
+            var scope = top_frame["scopeChain"][0];
+            Assert.Equal("local", scope["type"]);
+            Assert.Equal("IntAdd", scope["name"]);
+
+            Assert.Equal("object", scope["object"]["type"]);
+            CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 8, 4, scripts, scope["startLocation"]);
+            CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 14, 4, scripts, scope["endLocation"]);
+
+            await cli.SendCommand("Debugger.resume", null, token);
+
+            var run_method = JObject.FromObject(new
+            {
+                expression = "window.setTimeout(function() { load_wasm_page_without_assets(); }, 1);"
+            });
+            await cli.SendCommand("Runtime.evaluate", run_method, token);
+            await Task.Delay(1000, token);
+            run_method = JObject.FromObject(new
+            {
+                expression = "window.setTimeout(function() { reload_wasm_page(); }, 1);"
+            });
+            await cli.SendCommand("Runtime.evaluate", run_method, token);
+            await Task.Delay(1000, token);
+            await insp.WaitFor(Inspector.READY);
+            await EvaluateAndCheck(
+                "window.setTimeout(function() { invoke_add(); }, 1);",
+                "dotnet://debugger-test.dll/debugger-test.cs", 10, 8,
+                "IntAdd",
+                wait_for_event_fn: async (pause_location) =>
+                {
+                    Assert.Equal("other", pause_location["reason"]?.Value<string>());
+                    Assert.Equal(bp.Value["breakpointId"]?.ToString(), pause_location["hitBreakpoints"]?[0]?.Value<string>());
+
+                    var top_frame = pause_location["callFrames"][0];
+                    Assert.Equal("IntAdd", top_frame["functionName"].Value<string>());
+                    Assert.Contains("debugger-test.cs", top_frame["url"].Value<string>());
+
+                    CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 8, 4, scripts, top_frame["functionLocation"]);
+
+                    //now check the scope
+                    var scope = top_frame["scopeChain"][0];
+                    Assert.Equal("local", scope["type"]);
+                    Assert.Equal("IntAdd", scope["name"]);
+
+                    Assert.Equal("object", scope["object"]["type"]);
+                    CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 8, 4, scripts, scope["startLocation"]);
+                    CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 14, 4, scripts, scope["endLocation"]);
+                    await Task.CompletedTask;
+                }
+            );
+        }
+
     }
 }

src/mono/wasm/debugger/tests/debugger-test/debugger-driver.html

@@ -82,11 +82,14 @@
 		function invoke_add_with_parms (a, b) {
 			return App.int_add (a, b);
 		}
-				
 		function load_non_wasm_page () {
 			console.log("load_non_wasm_page")
 			window.location.replace("http://localhost:9400/non-wasm-page.html");
 		}
+		function load_wasm_page_without_assets () {
+			console.log("load_wasm_page_without_assets")
+			window.location.replace("http://localhost:9400/wasm-page-without-assets.html");
+		}
 		</script>
 		<script type="text/javascript" src="runtime-debugger.js"></script>
 		<script type="text/javascript" src="other.js"></script>

src/mono/wasm/debugger/tests/debugger-test/debugger-test.csproj

@@ -11,6 +11,7 @@
   <ItemGroup>
     <WasmExtraFilesToDeploy Include="debugger-driver.html" />
     <WasmExtraFilesToDeploy Include="non-wasm-page.html" />
+    <WasmExtraFilesToDeploy Include="wasm-page-without-assets.html" />
     <WasmExtraFilesToDeploy Include="other.js" />
     <WasmExtraFilesToDeploy Include="runtime-debugger.js" />
     <WasmExtraFilesToDeploy Include="weather.json" />

src/mono/wasm/debugger/tests/debugger-test/wasm-page-without-assets.html

@@ -0,0 +1,21 @@
+<!doctype html>
+<html lang="en-us">
+	<head>
+	</head>
+	<body>
+	<script type='text/javascript'>
+		var App = {
+			init: function () {
+				MONO.loaded_files = null;
+			},
+		};
+		function reload_wasm_page () {
+			window.location.replace("http://localhost:9400/debugger-driver.html");
+		}
+	</script>
+	<script type="text/javascript" src="runtime-debugger.js"></script>
+	<script type="text/javascript" src="other.js"></script>
+	<script async type="text/javascript" src="dotnet.js"></script>
+	Stuff goes here
+	</body>
+</html>