Skip to content

Latest commit

 

History

History
57 lines (40 loc) · 3.52 KB

debugging-wasm.md

File metadata and controls

57 lines (40 loc) · 3.52 KB
Raw

Debugging libraries

For building libraries or testing them without debugging, read:

Run the tests with debugger support

Run the selected library tests in the browser, e.g. System.Collections.Concurrent.Tests this way:

dotnet run -r browser-wasm -c Debug --project src/libraries/System.Collections/tests/System.Collections.Tests.csproj --debug --host browser -p:DebuggerSupport=true

where we choose browser-wasm as the runtime and by setting DebuggerSupport=true we ensure that tests won't start execution before the debugger will get attached. In the output, among others you should see:

Debug proxy for chrome now listening on http://127.0.0.1:58346/. And expecting chrome at http://localhost:9222/
App url: http://127.0.0.1:9000/index.html?arg=--debug&arg=--run&arg=WasmTestRunner.dll&arg=System.Collections.Concurrent.Tests.dll

The proxy's url/port will be used in the next step.

You may need to close all Chrome instances. Then, start the browser with debugging mode enabled:

chrome --remote-debugging-port=9222 <APP_URL>

Now you can choose an IDE to start debugging. Remember that the tests wait only till the debugger gets attached. Once it does, they start running. You may want to set breakpoints first, before attaching the debugger, e.g. setting one in src\libraries\Common\tests\WasmTestRunner\WasmTestRunner.cs on the first line of Main() will prevent any test to be run before you get prepared.

Debug with Chrome DevTools

Open chrome://inspect/#devices in a new tab in the browser you started. Select Configure:

image

and paste the address of proxy that was provided in the program output.

image

New remote targets will be displayed, select the address you opened in the other tab by clicking Inspect.

image

A new window with Chrome DevTools will be opened. In the tab sources you should look for file:// directory. There you can browse through libraries file tree and open the source code. It can take some time to load the files. When the IDE is ready the tests will start running. You cannot set a breakpoints in Chrome DevTools before the files get loaded, so you might want to use the first run for setting the initial breakpoint in WasmTestRunner.cs and then rerun the app. DevTools will stop on the previously set breakpoint and you will have time to set breakpoints in the libs you want to debug and click Resume.

Debug with VS Code

Add following configuration to your .vscode/launch.json:

        {
            "name": "Libraries",
            "request": "attach",
            "type": "chrome",
            "address": "localhost",
            "port": <PROXY'S_PORT>
        }

Set at least one breakpoint in the libraries, you can do it initially in WasmTestRunner.cs.

Run the configuration and be patient, it can take some time. Wait till VS Code will get stopped in WasmTestRunner. Set breakpoints in the libs you want to debug and click Resume. image