opam pin + opam install discrepancy: failing to fetch (or cache) build-directory (and hence failing to build)

[chetmurthy]

I have some scripts that use opam commands to install/uninstall collections of related packages. In the process of using them, I found a bug in the fetching/caching of build-directories. Here are two scripts: the first produces an error, the second does not. I append first the two scripts, and then the error, and then the output of "opam config report". Also, if I uncomment the last line of DOIT.BAD (which runs the install command a second time), then it works the second time.

I suppose there is something wrong with the way "--working-dir" is working.

DOIT.BAD:

opam remove -y not-ocamlfind
opam pin -y -n add not-ocamlfind https://github.com/chetmurthy/not-ocamlfind.git
(cd not-ocamlfind && opam install -y --working-dir .)
# (cd not-ocamlfind && opam install -y --working-dir .)

DOIT.OK:

opam remove -y not-ocamlfind
opam pin -y -n add not-ocamlfind https://github.com/chetmurthy/not-ocamlfind.git
(cd not-ocamlfind && opam install -y .)

Failed output of DOIT.BAD:

+ opam remove -y not-ocamlfind
The following actions will be performed:
  ⊘ remove not-ocamlfind 0.07.02*

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
⊘ removed   not-ocamlfind.0.07.02
Done.
+ opam pin -y -n add not-ocamlfind https://github.com/chetmurthy/not-ocamlfind.git
[NOTE] Package not-ocamlfind is currently pinned to git+file:///home/chet/Hack/Camlp5/src/ALL/not-ocamlfind#master (version 0.07.02).
[not-ocamlfind.0.07.02] synchronised (git+https://github.com/chetmurthy/not-ocamlfind.git)
not-ocamlfind is now pinned to git+https://github.com/chetmurthy/not-ocamlfind.git (version 0.07.02)
+ cd not-ocamlfind
+ opam install -y --working-dir .
[NOTE] Package not-ocamlfind is currently pinned to git+https://github.com/chetmurthy/not-ocamlfind.git (version 0.07.02).
not-ocamlfind is now pinned to git+file:///home/chet/Hack/Camlp5/src/ALL/not-ocamlfind#master (version 0.07.02)
The following actions will be performed:
  ∗ install not-ocamlfind 0.07.02*

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>

#=== ERROR while compiling not-ocamlfind.0.07.02 ==============================#
/home/chet/Hack/Opam-2.1.0/bin/opam: "chdir" failed on /home/chet/Hack/Opam-2.1.0/GENERIC/4.12.0~alpha3/.opam-switch/sources/not-ocamlfind: No such file or directory


<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
┌─ The following actions failed
│ λ build not-ocamlfind 0.07.02
└─ 
╶─ No changes have been performed

============================================================================

# opam config report
# opam-version         2.1.0~beta3 (0fd7ab6b9fe419177bdd74e30841cfb71584e5c1) 
# self-upgrade         no
# system               arch=x86_64 os=linux os-distribution=ubuntu os-version=20.04
# solver               builtin-mccs+glpk
# install-criteria     -removed,-count[hidden-version,changed],-count[version-lag,request],-count[version-lag,changed],-count[missing-depexts,changed],-changed
# upgrade-criteria     -removed,-count[hidden-version,changed],-count[version-lag,solution],-count[missing-depexts,changed],-new
# jobs                 7
# repositories         1 (http), 1 (version-controlled) (default repo at 72d9d430)
# pinned               9 (git)
# current-switch       4.12.0~alpha3
# read-state           Not_found

[rjbou]

Thanks for the detailed report! I'm able to reproduce easily, I'll take a look