Understanding why I am seeing precompilation on github actions. Cache partial miss

General Usage
1

I am seeing this message in my github actions logs:

  julia scripts/julia_dev_tooling/format.jl
  shell: /usr/bin/bash -e {0}
  env:
    JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
  Activating project at `~/work/biohaus/biohaus/scripts/julia_dev_tooling`
Precompiling project...
    863.3 ms  ✓ Glob
   1097.5 ms  ✓ Preferences
    510.4 ms  ✓ PrecompileTools
  25113.2 ms  ✓ CommonMark
    918.3 ms  ✓ CommonMark → CommonMarkMarkdownExt
  32835.5 ms  ✓ JuliaSyntax
  46553.2 ms  ✓ JuliaFormatter
  7 dependencies successfully precompiled in 79 seconds. 10 already precompiled.
[ Info: <messages from my script>

full logs

So I am seeing

7 dependencies successfully precompiled in 79 seconds. 10 already precompiled.

So it is at least partially hitting my cache since 10 were already precompiled.
Why is it not fully hitting it? Why are 7 being precompiled?
I can’t see any messages further up about new versions being installed,
and I shouldn’t since i have a manifest checked in, and i haven’t touched my dependencies at all in this PR.

I am using the standard julia-actions/cache action.

2

Setting the environment variable

JULIA_DEBUG=loading

will tell you why existing cache can’t be hit.