reverse dependencies

[tomberek]

Trying to understand some error cases i’m seeing during reviews using nix-review. Not sure exactly how --checkout commit/merge should be interpreted when there is a failure in one or the other.

For packages with many reverse dependencies, nix-review pr #### seem to fail often in this manner (see below). Not sure if this is yarn2nix specific or if there is an easy way to exclude that package to test if the failure is particular to it.

Same errors occur on Ubuntu/NixOS.

nix-review pr 58659
$ git fetch --force https://github.com/NixOS/nixpkgs staging:refs/nix-review/0 pull/58659/head:refs/nix-review/1
$ git worktree add /home/dev/.cache/nix-review/pr-58659-4/nixpkgs e82ef0841152c05b4abca0101a6033aa65472a9d
Preparing worktree (detached HEAD e82ef084115)
Checking out files: 100% (18773/18773), done.
HEAD is now at e82ef084115 btrbk: 0.27.1 -> 0.27.2 (#58651)
$ git merge --no-commit b62e1cd27e83922a6e82b6715530cebae3c1908f
Automatic merge went well; stopped before committing as requested
error: Use upstream https://github.com/moretea/yarn2nix
(use '--show-trace' to show detailed location information)
nix eval --json (import /nix/store/0gabypl11hzc11pj1ipq2rrdsb5k1xdc-nix-review-2.0.0/lib/python3.7/site-packages/nix_review/nix/evalAttrs.nix /tmp/tmpo81o_l63) failed to run, /tmp/tmpo81o_l63 was stored inspection
NixOS/nixpkgs#58659 failed to build
whereas, this seems better:

nix-review pr 58659 --checkout commit
$ git fetch --force https://github.com/NixOS/nixpkgs staging:refs/nix-review/0 pull/58659/head:refs/nix-review/1
$ git worktree add /home/dev/.cache/nix-review/pr-58659-5/nixpkgs b62e1cd27e83922a6e82b6715530cebae3c1908f
Preparing worktree (detached HEAD b62e1cd27e8)
Checking out files: 100% (18685/18685), done.
HEAD is now at b62e1cd27e8 curl: 7.64.0 -> 7.64.1
$ nix build --no-link --keep-going --max-jobs 8 --option build-use-sandbox true -f /home/dev/.cache/nix-review/pr-58659-5/build.nix
...

From Discourse (@timokau):
On a second look, the PR you mentioned targets staging. Probably
merge always tries to merge into nixpkgs master, not staging, which
is causing the issue and explains why commit works. I’m not sure if
Mic92 supports the staging use case, but please still create an issue to
find out