Error with make when switch from Zeronet to Alphanet (tezos-node)

Question

How to downgrade the version in: /home/chainacc/tezos/_opam/lib/js_of_ocaml-compiler/dune-package (manual fixing don't fix :) )

The error: (no warning before the make)

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
[ERROR] The compilation of cppo_ocamlbuild failed at "/home/chainacc/.opam/opam-init/hooks/sandbox.sh build jbuilder build -p cppo_ocamlbuild -j 15".
[ERROR] The compilation of cstruct failed at "/home/chainacc/.opam/opam-init/hooks/sandbox.sh build dune build -p cstruct -j 15".
[ERROR] The compilation of ocaml-migrate-parsetree failed at "/home/chainacc/.opam/opam-init/hooks/sandbox.sh build dune build -p ocaml-migrate-parsetree -j 15".

#=== ERROR while compiling ocaml-migrate-parsetree.1.2.0 ======================#
# context     2.0.1 | linux/x86_64 | ocaml-base-compiler.4.07.1 | git+https://gitlab.com/tezos/opam-repository.git#a0ce95cd2089a4d5e8ec9771a15b88a11a44f8ed
# path        ~/tezos/_opam/.opam-switch/build/ocaml-migrate-parsetree.1.2.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p ocaml-migrate-parsetree -j 15
# exit-code   1
# env-file    ~/.opam/log/ocaml-migrate-parsetree-19210-2628a0.env
# output-file ~/.opam/log/ocaml-migrate-parsetree-19210-2628a0.out
### output ###
# File "

> /home/chainacc/tezos/_opam/lib/js_of_ocaml-compiler/dune-package

", line 1, characters 11-15:
# 1 | (lang dune 1.10)
#                ^^^^
# Error: Version 1.10 of dune is not supported.
# Supported versions:
# - 0.0
# - 1.0 to 1.8


#=== ERROR while compiling cstruct.3.3.0 ======================================#
# context     2.0.1 | linux/x86_64 | ocaml-base-compiler.4.07.1 | git+https://gitlab.com/tezos/opam-repository.git#a0ce95cd2089a4d5e8ec9771a15b88a11a44f8ed
# path        ~/tezos/_opam/.opam-switch/build/cstruct.3.3.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p cstruct -j 15
# exit-code   1
# env-file    ~/.opam/log/cstruct-19210-e9cea8.env
# output-file ~/.opam/log/cstruct-19210-e9cea8.out
### output ###
# File "/home/chainacc/tezos/_opam/lib/sexplib/dune-package", line 1, characters 11-15:
# 1 | (lang dune 1.10)
#                ^^^^
# Error: Version 1.10 of dune is not supported.
# Supported versions:
# - 0.0
# - 1.0 to 1.8


#=== ERROR while compiling cppo_ocamlbuild.1.6.0 ==============================#
# context     2.0.1 | linux/x86_64 | ocaml-base-compiler.4.07.1 | git+https://gitlab.com/tezos/opam-repository.git#a0ce95cd2089a4d5e8ec9771a15b88a11a44f8ed
# path        ~/tezos/_opam/.opam-switch/build/cppo_ocamlbuild.1.6.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build jbuilder build -p cppo_ocamlbuild -j 15
# exit-code   1
# env-file    ~/.opam/log/cppo_ocamlbuild-19210-40fffe.env
# output-file ~/.opam/log/cppo_ocamlbuild-19210-40fffe.out
### output ###
# [...]
# File "test/jbuild", line 96, characters 26-39:
# 96 |   (action (with-stdout-to test.cppo.out (run ${bin:cppo} ${<})))))
#                                ^^^^^^^^^^^^^
# Warning: Aliases must not have targets, this target will be ignored.
# This will become an error in the future.
# File "/home/chainacc/tezos/_opam/lib/js_of_ocaml-compiler/dune-package", line 1, characters 11-15:
# 1 | (lang dune 1.10)
#                ^^^^
# Error: Version 1.10 of dune is not supported.
# Supported versions:
# - 0.0
# - 1.0 to 1.8



<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
┌─ The following actions failed
│ λ build cppo_ocamlbuild         1.6.0
│ λ build cstruct                 3.3.0
│ λ build ocaml-migrate-parsetree 1.2.0

Answer 1

As zeronet aims to be a testing network (that could be based on experimental branches) it may uses packages which are not (yet) used in the mainnet/alphanet/master branches.

To avoid packages conflicts, a convenient solution is to use an opam switch dedicated to zeronet (in addition to git worktree).

After removing the _opam directory at the root of the repository, you should run the make build-deps command. A new opam switch with all the dependencies will be automatically built. Dont't forget to run eval $(opam env) before running make.