feat(tasks): allow skipping tasks with the flag

[noirbizarre]

This PR add a -T/--skip-tasks flag allowing to skip template tasks execution.

Some known use cases I have:

• while testing my template, I want to be able to perform multiple rendering with the extensions actives but without running tasks (which may be slow or depending on connection...)
• when applying a template with some bootstrap tasks on an existing project, I want to be able to skip the bootstrap tasks because I know they will fail
• when applying a third party template that I trust, I want to only skip tasks for some reason (known to break, not compatible with the environment...)

Should fix #1415

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.29%. Comparing base (0fb2d06) to head (05c1762).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1561      +/-   ##
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+ Coverage   97.28%   97.29%   +0.01%     
==========================================
  Files          48       48              
  Lines        4603     4621      +18     
==========================================
+ Hits         4478     4496      +18     
  Misses        125      125              

Flag	Coverage Δ
unittests	97.29% <100.00%> (+0.01%)	⬆️

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[pawamoy]

Looks solid 🙂

Do I understand correctly that passing --skip-tasks means I don't have to also pass --trust?

[noirbizarre]

No, you still have to pass --trust (if you want to have jinja extensions loaded), but if you have --trust --skip-tasks only extension will be loaded (and migrations applied in case of update) while --trust will load extension and execute tasks (and apply migrations in the case of update).
In fact it doesn't touch the --trust behavior, just skipping tasks, whether the template is trusted or not (but in the second case, tasks are disabled by security, not from user intent)

[pawamoy]

OK yes that makes sense.

[pawamoy]

Two suggestions regarding readability and then I'll have nothing left to say I think 😄

[pawamoy]

LGTM!

[sisp]

We also need to document this setting here.

[noirbizarre]

PR updated with the setting documentation 👍🏼

[sisp]

Just some final 🤞 docs suggestions, @noirbizarre. I'll be happy to merge afterwards.

[sisp]

Fantastic, thanks @noirbizarre! 🙏

[yajo]

Sorry for being late to the party.

I think that, if you pass this flag, it should be taken into account around here to avoid marking the template as unsafe if it's only because of tasks but you're skipping them:

copier/copier/main.py

Lines 233 to 234 in 70aa69f

	if self.template.tasks:
	features.add("tasks")

[sisp]

@yajo I think that's the same thought that I had, but we decided against it in that discussion. WDYT?

[yajo]

Consider migrations. Even if the template uses migrations, we only mark it as unsafe if the current update will trigger them.

In the same fashion, if it has tasks but you're ignoring them, there's no unsafety produced by tasks. Other unsafety criteria should still be honored, but not that one.