I am trying to wrap my head around how to make use of variables defined at different positions inside a Bitbucket pipeline.

I am using a Docker image based on python:3.8-slim-bookworm, because reasons. Except for installing some packages, e.g. awscli, the image is unmodified.

I separate the definition of steps from the actual pipelines, where the order of steps for different branches is outlined.

Inside a script block,

script:
 - FRUIT="banana"
 - echo $FRUIT
 - echo "$FRUIT"
 - echo "${FRUIT}"
 - echo "the ${FRUIT} is not an apple"

 - ALMOST_PI=3
 - echo $(($PI * 5))

I can define and use variables, even arithmetic expansion works.

I can export and use variables as well.

script:
  - export FUNCTION_NAME="do-stuff"
  - export EXTENSION"="zip"
  - export ZIP_FILE="${FUNCTION_NAME}.${EXTENSION}"
  - echo $ZIP_FILE

This gives do-stuff.zip

However, the following does not work!

I can export and use variables as well.

step:
  environment:
    VEGETABLE: "potato"
  script:
    - echo $VEGETABLE

This gives just nothing.

Moreover, variables can be declared in a variables block on the same indentation level than image, definitions, steps and pipelines.

variables:
   ARTIFACTS_DIR: &artifacts-dir "${BITBUCKET_CLONE_DIR}/artifacts"

However, so far I could not make use of this declaration inside a script block in a step. Instead, I declare the ARTIFACTS_DIR time and time again in each step. This works, but it is cumbersome.