Steps to Reproduce:
Check this image:

Does this issue occur when all extensions are disabled?: No
Can you provide a copy/pastable task that I can use to try to repro with?
@alexr00 We are seeing tons of VS Code Insider user reports involving the error "The task provider for "C/C++" tasks unexpectedly provided a task of type "shell": https://github.com/microsoft/vscode-cpptools/issues/5388 . It doesn't appear with VS Code non-Insiders and repros with our insiders and non-insiders versions of our C/C++ extension so it seems like it's a VS Code Insiders regression and not a bug with our extension. I don't understand the repro yet though. This started 6-7 days ago.
Hi @alexr00, again a ton of reports about "The task provider for "C/C++" tasks unexpectedly provided a task of type "shell" for @PlatformIO. How could we fix it?
@ivankravets It looks to be a two-fold issue... recent change in VSCode has exposed an configuration issue in the C/C++ extension. Explained here: https://github.com/microsoft/vscode-cpptools/issues/5388#issuecomment-625275433, with a fix to hide that message due in the next few days: https://github.com/microsoft/vscode-cpptools/issues/5388#issuecomment-626082004
@ivankravets We shipped a fix for 0.28.0-insiders3 Friday evening, but we found some last minute issues so 0.28.0 won't be released till Tuesday evening probably.
Thanks, @sean-mcmanus, for the updates!
I'm still receiving this message The task provider for "composer" tasks unexpectedly provided a task of type "undefined" in vscode 1.45.1 from Composer Companion extension, I'm the extension's author. Did something changed in vscode.Task's or TaskDefinition implementation? I can't find from where that 'undefined' type could be coming from or what I should change.
@faelv Look for code that creates vscode.Task objects with the source field being undefined.
Thanks for the reply @sean-mcmanus. Source is "composer", a string... maybe I should wait for a new build.
Thanks for the reply @sean-mcmanus. Source is
"composer", a string... maybe I should wait for a new build.
Just pointing out that it keeps happening in 1.46.1
@faelv There's a difference between the "source" and "type" (that I didn't realize previously), so you should double check that all the "type" strings are not undefined. You can refer to the PR at https://github.com/microsoft/vscode-cpptools/pull/5585/files where I fixed an issue where we were using an incorrect "source" of type "shell" instead of "C/C++" where the "type" is "shell". We have another work in progress PR to try to change the "type" to "cppbuild" at https://github.com/microsoft/vscode-cpptools/pull/5659 that may be helpful as well.
My assumption is this is an error with the Composer Companion extension. If you think it's a VS Code bug still, you may want to file a new issue and/or provide more repro info and explanation.
Hey @alexr00, this issue might need further attention.
@salda, you can help us out by closing this issue if the problem no longer exists, or adding more information.
Most helpful comment
@ivankravets We shipped a fix for 0.28.0-insiders3 Friday evening, but we found some last minute issues so 0.28.0 won't be released till Tuesday evening probably.