Improve instructions for debugging. (#4390)

Author: davidmorgan

build_runner/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.12.3-wip
+
+- Improved debugging instructions in README.md.
+
 ## 2.12.2
 
 - Bug fix: don't crash if `applies_builders` in `build.yaml` mentions an

build_runner/README.md

@@ -216,10 +216,21 @@ For testing builders, see the [`build_test` package](https://pub.dev/packages/bu
 
 ## Debugging builds
 
-To debug the build process, note that `build_runner` spawns a child process to run
-the build.
-Options used to spawn this process can be customized, which allows attaching a debugger:
+To debug the build process, note that `build_runner` spawns a child process to
+run the build. So, the args that turn on debugging must be passed through
+`build_runner` to the child process using `--dart-jit-vm-arg`, for example:
 
 ```shell
 dart run build_runner build --dart-jit-vm-arg=--observe --dart-jit-vm-arg=--pause-isolates-on-start
 ```
+
+The args in the example will cause the child process to output a URL for debugging:
+
+```
+The Dart DevTools debugger and profiler is available at:
+http://127.0.0.1:8181/3xXtAPE8msc=/devtools/?uri=ws://127.0.0.1:8181/3xXtAPE8msc=/ws
+```
+
+To use your IDE to debug, launch a "remote debug" session. For example in
+VSCode the remote debug action is called "Debug: Attach to Dart Process". It
+will ask for the URL to connect to: paste in the one that was printed.

build_runner/pubspec.yaml

@@ -1,5 +1,5 @@
 name: build_runner
-version: 2.12.2
+version: 2.12.3-wip
 description: A build system for Dart code generation and modular compilation.
 repository: https://github.com/dart-lang/build/tree/master/build_runner
 resolution: workspace

build_test/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.5.11-wip
+
+- Use `build_runner` 2.12.3-wip.
+
 ## 3.5.10
 
 - Use `build_runner` 2.12.2.

build_test/pubspec.yaml

@@ -1,6 +1,6 @@
 name: build_test
 description: Utilities for writing unit tests of Builders.
-version: 3.5.10
+version: 3.5.11-wip
 repository: https://github.com/dart-lang/build/tree/master/build_test
 resolution: workspace
 
@@ -10,7 +10,7 @@ environment:
 dependencies:
   build: ^4.0.0
   build_config: ^1.0.0
-  build_runner: '2.12.2'
+  build_runner: '2.12.3-wip'
   built_collection: ^5.1.1
   crypto: ^3.0.0
   glob: ^2.0.0