Shell is evaluated even before running the task

[ronlut]

• Task version: v3.0.0-preview3
• OS: mac

Hi, thanks for the great work!
Task v3 evaluates shell commands before running the task - for example when running task --list.
This is not the behaviour in v2 and doesn't make sense as a lot of tasks depend on previous tasks.

Example:

version: '3'

tasks:
  foo:
    desc: foo
    cmds:
      - echo $MSG
    env:
      MSG: {sh: 'sleep 10; echo hi'}

Running task --list will sleep for 10 seconds.
In v2 it will just work as expected :)

Same bug occurs under vars: so I guess it has to do with the shell evaluation.
If you point me into a direction that might cause this behaviour I can add a PR to fix it.
Thanks!

[andreynering]

Hi @ronlut,

It's possible that the behavior is completely different in the v3 branch currently as it was refactored a few days ago (and not yet released on the preview channel). It'd be nice if you could try it.

Or if you don't want to build from source, I plan to release the last v3 preview release soon (before it goes to stable).

[ronlut]

Checked with latest commit on v3 branch - bug still exists.

[andreynering]

Hi @ronlut,

I just figured out what's happening. Actually this is not a v3 issue, it's also on v2, but only starting on the v2.8.1 release, which was made later in the same day you opened this issue.

This was caused by #276 and #283, i.e. someone couldn't use variables on desc before this patch.

To be honest, I'm not sure about what to do here. That a valid feature request, but comes with this drawback of making stuff slow if you have slow dynamic variables (which people should usually avoid if possible).

[ronlut]

Hi, thanks for the reply.
I don't think it's only a problem with slow variables.
It may fail task --list in various scenarios. If you use vars somewhere in the shell it will fail as when running task --list you don't provide any vars - you just want to know what tasks are available.

[andreynering]

Perhaps we should skip errors on variables when using --list and just print a blank string

We could also set a timeout for these shell when on --list (1 second? 0.5?)

[mihi314]

Shell tab-completion is also affected by this. Which can make it very slow, or even not work at all when a command fails.

[rmmcnulty9]

Any updates on this? This seems like a pretty big regression to have in the code base for so many releases.

[andreynering]

Now in master, interpolation still work for desc but dynamic variables will not run at all for --summary and --list flags. I hope this is a good trade off.

[b4nst]

@andreynering I understand why we don't want dynamic variables being computed for --summary and --list but could they be at least redacted with something like <runtime-computed> because right now with this Taskfile:

version: '3'

vars:
  PROJECT_VERSION:
    sh: git describe --tags --always
    
tasks:
  echo:
    desc: Test task
    summary: |
      Echo '{{.PROJECT_VERSION}}'
    cmds:
      - echo {{.PROJECT_VERSION}}

We ends up with:

➜  task --summary echo                                                                                                                                                                                                                                                    10:48:54
task: echo

Echo ''

commands:
 - echo

Which is a bit misleading