optimisation: run CI only when code changes

[alexbassy]

problem:

CI is run for every change, e.g. README.md

solution:

check if out directory is different in CI

proposed solution/workflow

• build and export site

• generate hash of out directory

   find ./out -type f -print0 | xargs -0 sha1sum | sha1sum

  this:

  1. lists the files in the out directory as a long string
  2. generate hash for all files with sha1sum
  3. hash that output, to see if there were any changes

• compare this with the hash from the previous build

  • if it has changed, upload the hash as a new artifact and continue with the rest of the steps in the workflow
  • if it has not changed, do nothing

why i will not do this

• premature optimisation
• might introduce subtle bugs/conditions for deployment?
• i might want to periodically deploy new builds