Debugger restart error if debug icon is pressed after a stop

[rsora]

Describe the bug
Some times the debug button behavior triggers a failed launch of openocd probably due to a bug in the GUI code

To Reproduce
Steps to reproduce the behavior:

1. Open a sketch
2. Connect a debug enabled board (like an Arduino Zero)
3. Select Sketch > Optimize for Debugging
4. Upload Sketch
5. Click the Debug Button
   
6. Add a breakpoint in your sketch
7. Click "Continue" in the Debugger control bar
   
8. Click "Stop" in the Debugger control bar
9. Click the Debug button again and wait
10. See the error (also reported in the screenshot below)

Failed to launch OpenOCD GDB Server: Error: spawn /home/rsora/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd ENOENT

Please note that the last 3 steps may need to be performed a few times before seeing the failure.
Reproducibility is not consistent

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: we were able to reporduce the issue on Linux and MacOS and Windows
• Version: 2.0.0-beta.3-snapshot.9fb8c4b
• Date: 2021-02-25T15:29:51.087Z
• CLI Version: 0.16.1 alpha [76f55490]

[kittaakos]

It appears to be an issue with Theia. When starting the very first debug session from the toolbar right after the app startup, I can see the following debug configuration (note that cwd is correctly resolved from '{workspaceRoot} to my actual FS location). When starting the next session, it is not resolved.

Config after the first start:

{
  "id": 0,
  "configuration": {
    "cwd": "/Users/akos.kitta/Documents/Arduino/xxx",
    "name": "Arduino",
    "request": "launch",
    "type": "cortex-debug",
    "executable": "/var/folders/k3/d2fkvv1j16v3_rz93k7f74180000gn/T/arduino-sketch-062822A8FE3586E9C342920A463F4CF4/xxx.ino.elf",
    "servertype": "openocd",
    "serverpath": "/Users/akos.kitta/Library/Arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd",
    "armToolchainPath": "/Users/akos.kitta/Library/Arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/",
    "configFiles": [
      "/Users/akos.kitta/Library/Arduino15/packages/arduino/hardware/samd/1.8.11/variants/arduino_zero/openocd_scripts/arduino_zero.cfg"
    ],
    "debuggerArgs": [],
    "swoConfig": {
      "enabled": false,
      "decoders": [],
      "cpuFrequency": 0,
      "swoFrequency": 0,
      "source": "probe"
    },
    "graphConfig": [],
    "preLaunchCommands": [],
    "postLaunchCommands": [],
    "preAttachCommands": [],
    "postAttachCommands": [],
    "preRestartCommands": [],
    "postRestartCommands": [],
    "searchDir": [],
    "toolchainPath": "/Users/akos.kitta/Library/Arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/",
    "toolchainPrefix": "arm-none-eabi",
    "extensionPath": "/Users/akos.kitta/git/arduino-ide/plugins/cortex-debug/extension",
    "flattenAnonymous": false,
    "registerUseNaturalFormat": true
  }
}

Config after the second start:

{
  "id": 1,
  "configuration": {
    "cwd": "${workspaceRoot}",
    "name": "Arduino",
    "request": "launch",
    "type": "cortex-debug",
    "executable": "/var/folders/k3/d2fkvv1j16v3_rz93k7f74180000gn/T/arduino-sketch-062822A8FE3586E9C342920A463F4CF4/xxx.ino.elf",
    "servertype": "openocd",
    "serverpath": "/Users/akos.kitta/Library/Arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd",
    "armToolchainPath": "/Users/akos.kitta/Library/Arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/",
    "configFiles": [
      "/Users/akos.kitta/Library/Arduino15/packages/arduino/hardware/samd/1.8.11/variants/arduino_zero/openocd_scripts/arduino_zero.cfg"
    ],
    "debuggerArgs": [],
    "swoConfig": {
      "enabled": false,
      "decoders": [],
      "cpuFrequency": 0,
      "swoFrequency": 0,
      "source": "probe"
    },
    "graphConfig": [],
    "preLaunchCommands": [],
    "postLaunchCommands": [],
    "preAttachCommands": [],
    "postAttachCommands": [],
    "preRestartCommands": [],
    "postRestartCommands": [],
    "searchDir": [],
    "toolchainPath": "/Users/akos.kitta/Library/Arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/",
    "toolchainPrefix": "arm-none-eabi",
    "extensionPath": "/Users/akos.kitta/git/arduino-ide/plugins/cortex-debug/extension",
    "flattenAnonymous": false,
    "registerUseNaturalFormat": true
  }
}

[kittaakos]

Found it; it is crazy.

When one starts the debug session, the cortex-debug VSX will force to stop on entry. The debugger halts the debug session, and opens the editor of the directories.data/packages/arduino/hardware/samd/1.8.11/cores/arduino/cortex_handlers.c file. This cortex_handlers.c file is outside of the workspace, so when the user starts another debug session, this current editor (cortex_handlers.c) will be used as the anchor to calculate the workspace root, but it is outside of the workspace. So the cwd cannot be resolved against the ${workspaceRoot} variable. It will remain undefined and breaks the debug config.

Workaround for the time being:

• Open the app,
• Start the debug session from the toolbar,
• Stop the debug session,
• Select the sketch editor (so that it has the focus and will become the current widget),
• Start the debug session from the toolbar (Now it works.)

This is the point where we need to customize the default Theia behavior: https://github.com/eclipse-theia/theia/blob/f8bcc19eba884cbd64112aeb691e8c97aad87197/packages/workspace/src/browser/workspace-variable-contribution.ts#L213.

Also, it would be great to configure cortex-debug not to stop on entry.