Add the --dry-run option

[alexandre-daubois]

Fix #18

Allows using the --dry-run option with both build and install command. This wasn't added the download command, as I'm not really sure it makes sense to have it.

[asgrim]

IMO this should be merged into configureDownloadBuildInstallOptions

[alexandre-daubois]

I'm not sure, because it would mean the download command could dry run. I'm not sure this really makes sense to dry run a download?

[asgrim]

I think that is the part that is confusing; whilst we do actually need to download to dry-run the build+install parts, we should be able to restore the PIE_WORKING_DIRECTORY to its previous state.

Running \Php\Pie\ComposerIntegration\ComposerIntegrationHandler::__invoke updates your ${PIE_WORKING_DIRECTORY}/pie.json (+${PIE_WORKING_DIRECTORY}/pie.lock) and subsequently updates {$PIE_WORKING_DIRECTORY}/vendor/... with the new install.

The correct approach for dry-run would be:

• Resolve dependency
• Back up pie.json+pie.lock+vendor
  • Run the Composer integration handler
  • If requested, run the build with dry run flag
  • If requested, run the install with dry run flag
• Restore the backups

BUT - perhaps a simpler way of doing this however, would be to sandbox the dry-run download by adding dry_run prefix or similar to $targetPlatformPath in \Php\Pie\Platform::getPieWorkingDirectory, so it is downloaded in isolation from someone's "real" PIE_WORKING_DIRECTORY; then after the dry-run download/build/install is complete, remove the pie working directory (checking it is only for a dry-run).

FWIW, this is one of the reasons I'd been avoiding implementing --dry-run; it is messy and non-trivial to implement correctly 😆

[alexandre-daubois]

Thank you for this complete insight! I think I'm going to close this PR. If we were to implement it, I think it should be started again from scratch, because the current implementation here is not what we want.

I'll link your comment in the issue for when I'll have a bit more time for this feature, or if someone wants to take over.

Thanks again!

[alexandre-daubois]

Thanks James, I addressed all your comments! I really like the dry-run:: and the fact it could be used later to check whether a dry run was launched or not.

[alexandre-daubois]

Closed as explained in #118 (comment)