Inconsistent Variable Expansion When Using {{.VAR}} in .env Files with Nested Variables

[WinkelCode]

When using a .env file to define environment variables that rely on other variables using {{.VAR}} template syntax, the variables sometimes expand inconsistently across task runs. The issue becomes more apparent as the variables become more deeply nested.

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Steps to Reproduce:

1. Create a Taskfile.yml:

   version: "3"
   
   dotenv: [".env"]
   
   vars:
     BASE_DIR_VAR: "/home/user"
     MID_DIR_VAR: "{{.BASE_DIR_VAR}}/nested"
     FINAL_DIR_VAR: "{{.MID_DIR_VAR}}/deeper"
     FULL_PATH_VAR: "{{.FINAL_DIR_VAR}}/file.txt"
   
   env:
     BASE_DIR_ENV: "/home/user"
     MID_DIR_ENV: "{{.BASE_DIR_ENV}}/nested"
     FINAL_DIR_ENV: "{{.MID_DIR_ENV}}/deeper"
     FULL_PATH_ENV: "{{.FINAL_DIR_ENV}}/file.txt"
   
   tasks:
     show_vars:
       cmds:
         - 'echo "FULL_PATH:     $FULL_PATH"'
         - 'echo "FULL_PATH2:    $FULL_PATH_2"'
         - 'echo "FULL_PATH_VAR: {{.FULL_PATH_VAR}}"'
         - 'echo "FULL_PATH_ENV: {{.FULL_PATH_ENV}}"'
       silent: true

2. Create a .env File:

   BASE_DIR=/home/user
   MID_DIR=$BASE_DIR/nested
   FINAL_DIR=$MID_DIR/deeper
   FULL_PATH=$FINAL_DIR/file.txt
   MID_DIR_2={{.BASE_DIR}}/nested
   FINAL_DIR_2={{.MID_DIR_2}}/deeper
   FULL_PATH_2={{.FINAL_DIR_2}}/file.txt

3. Run the task multiple times:

   task show_vars

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Sample Outputs:

$ task show_vars
FULL_PATH:     /home/user/nested/deeper/file.txt
FULL_PATH2:    /home/user/nested/deeper/file.txt
FULL_PATH_VAR: /home/user/nested/deeper/file.txt
FULL_PATH_ENV: /home/user/nested/deeper/file.txt

$ task show_vars
FULL_PATH:     /home/user/nested/deeper/file.txt
FULL_PATH2:    /nested/deeper/file.txt
FULL_PATH_VAR: /home/user/nested/deeper/file.txt
FULL_PATH_ENV: /home/user/nested/deeper/file.txt

$ task show_vars
FULL_PATH:     /home/user/nested/deeper/file.txt
FULL_PATH2:    /nested/deeper/file.txt
FULL_PATH_VAR: /home/user/nested/deeper/file.txt
FULL_PATH_ENV: /home/user/nested/deeper/file.txt

$ task show_vars
FULL_PATH:     /home/user/nested/deeper/file.txt
FULL_PATH2:    /deeper/file.txt
FULL_PATH_VAR: /home/user/nested/deeper/file.txt
FULL_PATH_ENV: /home/user/nested/deeper/file.txt

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• Task version:

$ task --version
Task version: 3.39.2 ()

• Operating system: macOS 15.1
• Experiments enabled: None