opam 2.0.10 • OCaml Changelog

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We are pleased to announce the release of opam 2.0.10.

Two subtle fixes are included in opam 2.0.10. These actually affect the ocaml package. Both of these are Heisenbugs - investigating what's going wrong on your system may well have fixed them, they were both found on Windows!

$(opam env --revert) is the reverse of the more familiar $(opam env) but it's effectively called by opam whenever you change switch. It has been wrong since 2.0.0 for the case where several values are added to an environment variable in one setenv update. For example, if a package included a setenv field of the form [PATH += "dir1:dir2"], then this would not be reverted, but [[PATH += "dir1"] [PATH += "dir2"]] would be reverted. As it happens, this bug affects the ocaml package, but it was masked by another setenv update in the same package.

The other fix is also to do with setenv. It can be seen immediately after creating a switch but before any additional packages are installed, as this Dockerfile shows:

FROM ocaml/opam@sha256:244b948376767fe91e2cd5caca3b422b2f8d332f105ef2c8e14fcc9a20b66e25
RUN sudo apt-get install -y ocaml-nox
RUN opam --version
RUN opam switch create show-issue ocaml-system
RUN eval $(opam env) ; echo $CAML_LD_LIBRARY_PATH
RUN opam install conf-which
RUN eval $(opam env) ; echo $CAML_LD_LIBRARY_PATH

Immediately after switch creation, $CAML_LD_LIBRARY_PATH was set to /home/opam/.opam/show-issue/lib/stublibs:, rather than /home/opam/.opam/show-issue/lib/stublibs:/usr/local/lib/ocaml/4.08.1/stublibs:/usr/lib/ocaml/stublibs

Opam installation instructions (unchanged):

From binaries: run
```
bash -c "sh <(curl -fsSL https://raw.githubusercontent.com/ocaml/opam/master/shell/install.sh) --version 2.0.10"
```
or download manually from the Github "Releases" page to your PATH. In this case, don't forget to run opam init --reinit -ni to enable sandboxing if you had version 2.0.0~rc manually installed or to update you sandbox script.
From source, using opam:
```
opam update; opam install opam-devel
```
(then copy the opam binary to your PATH as explained, and don't forget to run opam init --reinit -ni to enable sandboxing if you had version 2.0.0~rc manually installed or to update your sandbox script)
From source, manually: see the instructions in the README.

We hope you enjoy this new minor version, and remain open to bug reports and suggestions.

See full changelog

Fix reverting environment additions to PATH-like variables when several dirs added at once [#4861 @dra27]
Ensure setenv can use package variables defined during the build [#4841 @dra27]