Always allow running extension commands from the manifest project

[pdgendt]

When constructing the Manifest project, it fails with a ManifestImportFailed if projects aren't cloned.
This consequently has the effect that we can't run any West extension commands, not even from the manifest project itself.

The issue was first reported here: zephyrproject-rtos/zephyr#103832

Example using the example application:

$ west init -m https://github.com/zephyrproject-rtos/example-application --mr main my-workspace
$ cd my-workspace

Try running the example-west-command extension without west update:

$ west example-west-command "test"
usage: west [-h] [-z ZEPHYR_BASE] [-v] [-q] [-V] <command> ...
west: unknown command "example-west-command"; workspace /tmp/my-workspace does not define this extension command -- try "west help" and "west -vv status"

After west update:

$ west example-west-command "test"
--optional is None
required is test

[marc-hb]

Imports are always much more complicated than people think (click on the "Partial imports" label I just added) and incomplete imports are basically a lost cause. Maybe the error message should explicit that lost cause more clearly but I don't think it is worth trying to make things work when imports are incomplete.

I don't think this is specific to extensions either BTW: the state after west init but before any west update command has been run is IMHO a fragile, temporary "bootstrap" state that one should never stay in for long. I think we already saw other, confusing error messages in that state before.

Reminder: this is what west init demands when it completes:

=== Initialized. Now run "west update" inside...

@mbolivar , thoughts?

[marc-hb]

I think we already saw other, confusing error messages in that state before.

Looking at the git log I found 45762a0 and #664 that seem related?

Imports are always much more complicated than people think

[marc-hb]

@jasr93, @pdgendt I would like to close this was "won't fix" for the time being based on the considerations here and in zephyrproject-rtos/zephyr#103832. We can re-open if someone has a very convincing use case AND a tentative design that is not too complex.