Shell function variables not properly scoped in background jobs

[techbiz-sadakane-kazuma]

Shell function variables not properly scoped in background jobs

Description

When using shell functions with background jobs (&) in Taskfile, variables appear to be shared/overwritten across parallel executions, leading to incorrect values being processed.

Expected Behavior

Each background job should receive and process its unique loop variable:

Processing 1
Processing 2
Processing 3
Processing 4

Actual Behavior

All background jobs process the same (final) value:

Processing 4
Processing 4
Processing 4
Processing 4

Minimal Reproduction Case

Taskfile.yml:

version: '3'

tasks:
  test_parallel:
    cmds:
      - |
        myfunc() {
          local val="$1"
          echo "Processing $val"
          # ... further processing
        }
        for v in 1 2 3 4; do
          sleep 1
          myfunc "$v" &
        done
        wait

Run: task test_parallel

Working Comparison

The same code works correctly when executed as a standalone shell script:

test.sh:

#!/bin/bash
myfunc() {
  local val="$1"
  echo "Processing $val"
  # ... further processing
}
for v in 1 2 3 4; do
  sleep 1
  myfunc "$v" &
done
wait

Output: Correctly shows "Processing 1", "Processing 2", etc.

Environment

• Taskfile version: 3
• Shell: bash

Additional Context

This appears to be related to how Taskfile handles shell execution context and variable scoping in background processes. The workaround is to call the external script (bash test.sh), but it would be helpful to understand if this is expected behavior or if there's a way to make inline shell functions work correctly with background jobs.

Question

Is this expected behavior due to how Taskfile executes shell commands, or is there a recommended way to achieve proper variable scoping for background jobs within Taskfile?

[trulede]

You could try to do this with the commands you want to run in the "background":
https://taskfile.dev/usage/#looping-over-dependencies
which because deps (i.e. your background conmmands) are run in parallel, it would achieve the same effect.

Otherwise, interesting problem.