Lazy global dynamic variable

[lockieluke]

Only load global variables with SH when the task needs it:

version: '3'
vars:
  MESSAGE:
    sh: sleep 5 && echo "WORLD"

tasks:
  print:
    cmds:
      - echo "HELLO {{.MESSAGE}}"

  print-no-wait:
    cmds:
      - echo "PRINT THIS INSTANTLY"

Other tasks that don't need the variable should not have it loaded

[vctls]

Just noticed that global dynamic variables are evaluated each time a task is run.
This can indeed become a performance problem. It could at least be documented.

I don't see many workarounds in the meantime.
Commands that take time should not be used in global dynamic variables but rather sub-commands or task dependencies.
Or, you could add conditions in the expression itself. Local variables aren't available, but, for example, the TASK variable is:

vars:
  FOO:
    sh: |-
      {{ if .TASK | contains "bar" }}sleep 2 && echo baz{{end}}

This is kind of ugly and cumbersome, but can be used with task namespaces in order to confine the problem to the tasks that actually need that variable.
I suppose long running command results could also be cached, when possible.