Canceling default build task via launch config re-appears

[miguelsolorio]

Testing #81637

Steps:

1. Create two default build tasks in your tasks.json
2. Use the new "preLaunchTask": "${defaultBuildTask}" on a launch config
3. Launch a session
4. When prompted to choose a build task, hit cancel
5. 🐛 the same prompt appears twice

I expected that when I first hit Cancel that it would either cancel the entire sequence (build + launch) or at least cancel the build. Feels like a bug that I'm asked twice.

VS Code version: Code - Insiders 1.39.0-insider (313ede6, 2019-10-01T05:39:51.694Z)
OS version: Darwin x64 18.7.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-7920HQ CPU @ 3.10GHz (8 x 3100)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled oop_rasterization: disabled_off protected_video_decode: unavailable_off rasterization: enabled skia_deferred_display_list: disabled_off skia_renderer: disabled_off surface_synchronization: enabled_on video_decode: enabled viz_display_compositor: disabled_off webgl: enabled webgl2: enabled
Load (avg)	1, 2, 2
Memory (System)	16.00GB (0.02GB free)
Process Argv	-psn_0_3695494
Screen Reader	no
VM	0%

Extensions (28)

Extension	Author (truncated)	Version
mock-debug	and	0.35.1
vscode-eslint	dba	1.9.1
prettier-vscode	esb	2.3.0
vscode-open-in-github	fab	1.2.1
vscode-pull-request-github-insiders	Git	2019.9.38342
todo-tree	Gru	0.0.156
svg	joc	1.0.2
vscode-colorize	kam	0.8.13
vscode-azureappservice	ms-	0.16.0
vscode-azurestorage	ms-	0.7.1
vscode-docker	ms-	0.8.1
python	ms-	2019.9.34911
remote-containers	ms-	0.79.0
remote-ssh-edit-nightly	ms-	2019.10.900
remote-ssh-explorer-nightly	ms-	2019.10.900
remote-ssh-nightly	ms-	2019.10.900
azure-account	ms-	0.8.5
vscode-typescript-tslint-plugin	ms-	1.2.2
cloudenv	ms-	1.0.899
cloudenv-extensions	ms-	1.0.899
vsliveshare	ms-	1.0.905
azurerm-vscode-tools	msa	0.7.0
rescuetime	Res	1.0.1
code-settings-sync	Sha	3.4.3
notification-tester	svi	2.1.3
ayu	tea	0.18.0
errorlens	use	2.7.1
vscode-open-in-github	ziy	1.3.6

(5 theme extensions excluded)

[miguelsolorio]

This also happens when I have an empty tasks.json file, it will then ask the same question 3x.

[alexr00]

This happens because resolve variables is essentially called twice :(

[dbaeumer]

This is IMO still unhappy for a user. If I cancel the task picker I get this:

I would rather expect that the whole debug attempt is canceled and that the task quick pick contains an entry 'Continue debugging without prelauch task`

[alexr00]

I don't think it makes sense to have a "Continue debugging without prelaunch task" in the quick pick. The person who added the launch config specified that the prelaunch task should be ${defaultBuildTask}. Debug could have a different message there that offers to debug without the prelaunch task. @isidorn what do you think?

[isidorn]

Pressing escape should just quit the whole operation. Debugging should not start.
User should not get spammed with error messages. It is a user action, no explanation is needed that he just quit it.
If the user wants to start without a prelaunch task he should edit his launch.json