defauls packages are always installed regardless of the channels option

I tipically use setup-miniconda to install packages from two or three channels, conda-forge, robotology or robostack. I never need/want to install packages from defaults. I tought that by using the channels options as shown in https://github.com/conda-incubator/setup-miniconda#example-4-conda-options the defaults channels should have low priority by default, but even in that case, if i try to install the compilers meta-package, packages from defaults are installed:

See https://github.com/traversaro/setup-miniconda-always-uses-default-mre/runs/3199430212 (related job: https://github.com/traversaro/setup-miniconda-always-uses-default-mre/blob/main/.github/workflows/install-compilers-only-conda-forge-based-on-ex4.yml) for an example of this:

2021-07-30T06:55:37.1491185Z   + _libgcc_mutex                      0.1  conda_forge    conda-forge/linux-64       3 KB
2021-07-30T06:55:37.1492319Z   + _openmp_mutex                      4.5  1_gnu          conda-forge/linux-64      22 KB
2021-07-30T06:55:37.1499003Z   + binutils                        2.36.1  hdd6e379_2     conda-forge/linux-64      27 KB
2021-07-30T06:55:37.1500414Z   + binutils_impl_linux-64          2.36.1  h193b22a_2     conda-forge/linux-64      10 MB
2021-07-30T06:55:37.1501953Z   + binutils_linux-64                 2.36  hf3e587d_33    conda-forge/linux-64      22 KB
2021-07-30T06:55:37.1503097Z   + bzip2                            1.0.8  h7f98852_4     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1504025Z   + c-ares                          1.17.1  h7f98852_1     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1505036Z   + c-compiler                       1.2.0  h7f98852_0     conda-forge/linux-64       6 KB
2021-07-30T06:55:37.1506366Z   + ca-certificates              2021.5.30  ha878542_0     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1507325Z   + cmake                           3.21.1  h8897547_0     conda-forge/linux-64      15 MB
2021-07-30T06:55:37.1508214Z   + compilers                        1.2.0  ha770c72_0     conda-forge/linux-64       5 KB
2021-07-30T06:55:37.1509182Z   + cxx-compiler                     1.2.0  h4bd325d_0     conda-forge/linux-64       6 KB
2021-07-30T06:55:37.1510125Z   + expat                            2.4.1  h9c3ff4c_0     conda-forge/linux-64     182 KB
2021-07-30T06:55:37.1512088Z   + fortran-compiler                 1.2.0  h1990efc_0     conda-forge/linux-64       6 KB
2021-07-30T06:55:37.1513160Z   + gcc_impl_linux-64                9.3.0  h6df7d76_17    pkgs/main/linux-64        45 MB
2021-07-30T06:55:37.1514070Z   + gcc_linux-64                     9.3.0  hf25ea35_33    conda-forge/linux-64      23 KB
2021-07-30T06:55:37.1515034Z   + gfortran_impl_linux-64           9.3.0  hc4a2995_19    conda-forge/linux-64      10 MB
2021-07-30T06:55:37.1516018Z   + gfortran_linux-64                9.3.0  hdc58fab_33    conda-forge/linux-64      23 KB
2021-07-30T06:55:37.1516956Z   + gxx_impl_linux-64                9.3.0  hbdd7822_17    pkgs/main/linux-64         9 MB
2021-07-30T06:55:37.1518070Z   + gxx_linux-64                     9.3.0  h3fbe746_33    conda-forge/linux-64      23 KB
2021-07-30T06:55:37.1519332Z   + kernel-headers_linux-64         2.6.32  he073ed8_14    conda-forge/noarch       708 KB
2021-07-30T06:55:37.1520397Z   + krb5                            1.19.2  hcc1bbae_0     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1521329Z   + ld_impl_linux-64                2.36.1  hea4e1c9_2     conda-forge/linux-64     667 KB
2021-07-30T06:55:37.1522274Z   + libcurl                         7.78.0  h2574ce0_0     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1523413Z   + libedit                   3.1.20191231  he28a2e2_2     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1524337Z   + libev                             4.33  h516909a_1     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1525294Z   + libgcc-devel_linux-64            9.3.0  hb95220a_17    pkgs/main/linux-64         3 MB
2021-07-30T06:55:37.1526240Z   + libgcc-ng                       11.1.0  hc902ee8_4     conda-forge/linux-64     909 KB
2021-07-30T06:55:37.1527208Z   + libgfortran-ng                   9.4.0  h69a702a_4     conda-forge/linux-64      18 KB
2021-07-30T06:55:37.1528163Z   + libgfortran5                     9.4.0  h62347ff_4     conda-forge/linux-64       2 MB
2021-07-30T06:55:37.1529096Z   + libgomp                         11.1.0  hc902ee8_4     conda-forge/linux-64     428 KB
2021-07-30T06:55:37.1530039Z   + libnghttp2                      1.43.0  h812cca2_0     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1530981Z   + libssh2                          1.9.0  ha56f1ee_6     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1531966Z   + libstdcxx-devel_linux-64         9.3.0  hf0c5c8d_17    pkgs/main/linux-64        11 MB
2021-07-30T06:55:37.1533138Z   + libstdcxx-ng                    11.1.0  h56837e0_4     conda-forge/linux-64       4 MB
2021-07-30T06:55:37.1534059Z   + libuv                           1.42.0  h7f98852_0     conda-forge/linux-64       1 MB
2021-07-30T06:55:37.1534951Z   + lz4-c                            1.9.3  h9c3ff4c_0     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1535858Z   + make                               4.3  hd18ef5c_1     conda-forge/linux-64     507 KB
2021-07-30T06:55:37.1536747Z   + ncurses                            6.2  h58526e2_4     conda-forge/linux-64     985 KB
2021-07-30T06:55:37.1537621Z   + ninja                           1.10.2  h4bd325d_0     conda-forge/linux-64       2 MB
2021-07-30T06:55:37.1538525Z   + openssl                         1.1.1k  h7f98852_0     conda-forge/linux-64     Cached
2021-07-30T06:55:37.1539449Z   + pkg-config                      0.29.2  h36c2ea0_1008  conda-forge/linux-64     120 KB
2021-07-30T06:55:37.1540355Z   + rhash                            1.4.1  h7f98852_0     conda-forge/linux-64     192 KB
2021-07-30T06:55:37.1541271Z   + sysroot_linux-64                  2.12  he073ed8_14    conda-forge/noarch        32 MB
2021-07-30T06:55:37.1542147Z   + tk                              8.6.10  h21135ba_1     conda-forge/linux-64       3 MB
2021-07-30T06:55:37.1542999Z   + xz                               5.2.5  h516909a_1     conda-forge/linux-64     343 KB
2021-07-30T06:55:37.1543834Z   + zlib                            1.2.11  h516909a_1010  conda-forge/linux-64     106 KB
2021-07-30T06:55:37.1544716Z   + zstd                             1.5.0  ha95c52a_0     conda-forge/linux-64     Cached

The workaround that I am using know is to directly remove the defaults in the CI script, adding:

conda config --remove channels defaults

See for example https://github.com/dic-iit/kindyn-vio/blob/eb6617cbac34bb19526a01d5e43efc5654174d7c/.github/workflows/conda-ci.yml#L40 .

[jaimergp]

The action is using conda config --add channels, so I guess that should put conda-forge above in priority, but it’s obviously not happening. We might need to add a clear-preconfigured-channels option or similar to work around this.

Other things we can try in the meantime:

• Have you tried using an environment file with some channels specified in the file itself? This might hit another code path in conda.
• You can also provide a custom .condarc with the exact configuration you need.

[jaimergp]

Thanks for the report! I’ll look into this.

In the meantime, you might want to try channel-priority: strict too. Sorry, just saw you are indeed using it already.