dynamic variables evaluated twice

[mpeim]

What did I do?

While writing a task file, I wanted to have a variable A having a value depending on the value of another B that could be passed by the user when calling the task.
I wanted to have a third variable C to use to use the resulting value of A.
The whole taskfile is then imported in another one.

What happened?

Depending on the position of B in the command line, C would be evaluated twice with two different values of A.
This only occurs if the first example.

First example:

included.yml

version: '3.41'

vars:
  A: '{{.B | default (.A | default "nope")}}'
  C:
    sh: echo {{.A}}

tasks:
  test: echo {{.C}}

task.yml

version: '3.41'

includes:
  fail:
    taskfile: ./include.yml

Execution:

# executed two times
$ task fail:test -v B=two
task: [/home/mpeim.linux/debug-taskfiles] Not found - Using alternative (taskfile.yml)
task: dynamic variable: "echo nope" result: "nope"
task: dynamic variable: "echo two" result: "two"
task: "fail:test" started
task: [fail:test] echo "two"
two
task: "fail:test" finished

$ B=one task fail:test -v
task: [/home/mpeim.linux/debug-taskfiles] Not found - Using alternative (taskfile.yml)
task: dynamic variable: "echo one" result: "one"
task: "fail:test" started
task: [fail:test] echo "one"
one
task: "fail:test" finished

Second example:

include.yml stays the same.

taskfile.yml

version: '3.41'

# note that the field `taskfile` is not given
includes:
  fail: ./include.yml

Execution:

$ task fail:test -v B=yup
task: [/home/mpeim.linux/debug-taskfiles] Not found - Using alternative (taskfile.yml)
task: dynamic variable: "echo nope" result: "nope"
task: "fail:test" started
task: [fail:test] echo "nope"
nope
task: "fail:test" finished

$ B=one task fail:test -v
task: [/home/mpeim.linux/debug-taskfiles] Not found - Using alternative (taskfile.yml)
task: dynamic variable: "echo one" result: "one"
task: "fail:test" started
task: [fail:test] echo "one"
one
task: "fail:test" finished

Expectated behavior

I would expect the dynamic variable to be executed once in every case.

Version

3.41

Operating system

Linux lima-vpp3 5.15.0-130-generic #140-Ubuntu SMP Wed Dec 18 17:59:36 UTC 2024 aarch64 aarch64 aarch64 GNU/Linux

Experiments Enabled

With and without TASK_X_MAP_VARIABLES=1

[trulede]

@mpeim hi, do you still observe this problem with 3.43 or 3.44. I only observe the dynamic variable being evaluated once (using 3.43)

I do observe other problems; #2288 and also a one where include vars are available/applied after the included vars have been evaluated, which results in a default value being unexpectedly taken.

inc/Taskfile.yml

version: '3'

vars:
  A: '{{.A | default "c"}}'  # ***** expected to be "a"
  B: '{{.B | default .A}}'
  C:
    sh: echo {{.B}}
tasks:
  test:
    cmds:
      - echo "B is {{.B}}"
      - echo "C is {{.C}}"

Taskfile.yml

version: '3'

includes:
  inc:
    taskfile: inc/Taskfile.yml
    vars:
      A: a

tasks:
  default:
    cmds:
      - echo "{{.GREETING}}"

$ task inc:test -v
task: dynamic variable: "echo c" result: "c"
task: "inc:test" started
task: [inc:test] echo "B is c"
B is c
task: [inc:test] echo "C is c"
C is c
task: "inc:test" finished