nim-digger: program to build nim at any revision (including forks/PRs) (cf D's digger); useful for git bisect

[timotheecour]

git bisect start badrev goodrev
git bisect run zsh -c "source ~/.zshrc && nim=$nim_0190_X d_nim_build_simple_local --skipusercfg && $nimb c -r --skipusercfg --skipparentcfg $timn_D/tests/nim/all/t11021.nim"

note

• this requires knowing which csources hash was used to build a particular commit
• future csources2 should have a commit hash version controlled in nim repo so we can programmatically access it (EDIT: indeed, see nimBuildCsourcesIfNeeded in 1.5.1)

EDIT

• for new nim versions, use . ci/funs.sh && nimBuildCsourcesIfNeeded (which also already handles caching)
• for older nim versions relying on csources, figure out which csources hash to checkout based on git fetch --tags and git tag and finding the latest tag, the using a table lookup to identify the appropriate csources hash. Sadly necessary because of lack of prior design but not very complicated (followup here for this: nim-digger: program to build nim at any revision (including forks/PRs) (cf D's digger); useful for git bisect #332)

links

in D: https://github.com/CyberShadow/Digger

Digger can:
build and test D from git
build older versions of D
build D plus forks and pending pull requests
bisect D's history to find where regressions are introduced (or bugs fixed)

links

• made easier after refactor all code that builds csources nim-lang/Nim#17815
• choosenim devel --latest fails build dom96/choosenim#256 (comment)