cc @Ekleog

Are you sure this is correct? I just compiled before and after merging this, and get this diff, where result-2 is pre-diff and result is post-diff

$ diff -r result-2 result
diff -r result-2/bin/arc result/bin/arc
3c3
< exec /nix/store/5i9100265z0rdfvny48xz72kxnl141pc-php-with-extensions-7.4.8/bin/php /nix/store/bzvx97n5rjkvnj21gyiff1b4zx8knay1-arcanist-20200711/libexec/arcanist/bin/arc "$@"
---
> exec /nix/store/5i9100265z0rdfvny48xz72kxnl141pc-php-with-extensions-7.4.8/bin/php /nix/store/jj7qnd9dgwkin3kzhbqb29vxzqvl5f25-arcanist-20200711/libexec/arcanist/bin/arc "$@"
diff -r result-2/bin/phage result/bin/phage
3c3
< exec /nix/store/5i9100265z0rdfvny48xz72kxnl141pc-php-with-extensions-7.4.8/bin/php /nix/store/bzvx97n5rjkvnj21gyiff1b4zx8knay1-arcanist-20200711/libexec/arcanist/bin/phage "$@"
---
> exec /nix/store/5i9100265z0rdfvny48xz72kxnl141pc-php-with-extensions-7.4.8/bin/php /nix/store/jj7qnd9dgwkin3kzhbqb29vxzqvl5f25-arcanist-20200711/libexec/arcanist/bin/phage "$@"
Only in result/libexec/arcanist/src/parser/xhpast/bin: xhpast
Only in result/libexec/arcanist/support/xhpast: libxhpast.a
Only in result/libexec/arcanist/support/xhpast: node_names.hpp
Only in result/libexec/arcanist/support/xhpast: parser.yacc.o
Only in result/libexec/arcanist/support/xhpast: scanner.lex.o
Only in result/libexec/arcanist/support/xhpast: xhpast

This looks to me as though it were a regression, putting .o files in the nix store? as xhpast is, to the best of my understanding, a support tool for phab, that people don't have to manually call? But then, maybe I'm missing something :)

yeah xhpast is built and installed a line above. We def don't wanna intermediate build artifacts in the output.

Oh, I just understood the objective of this diff: to make .override work with a patches. If this is correct, maybe run make clean / make mrproper or similar for arcanist, and/or rm uninteresting files, before running the cp?

Darn, ok. I'll put up a fix later this evening.

@Ekleog Would you mind reviewing this again? I've removed the artifacts from the install output. Thanks!

Looks great to me! Actually, diff -r before/after this PR also shows it adds an executable (xhpast) though I'm not sure what exactly it is used for, and it now removes .hpp/.cpp yacc/lex files that were being leftover garbage, so it's a net plus even for people who don't use patches.

Thank you! :D

As for backports, this is along the fine line of whether it's a bug important enough to warrant backporting and the associated risks… I'd say it probably is not, and people who want it should probably import from unstable, so unless I hear an objecting voice I'm not going to backport to stable :)

IMO no urgent need for a backport.

Then again I live on unstable so perhaps I am not the best person to make that call