`spack develop`: convert to config (#35273)

Convert the 'develop' section of an environment to a dedicated configuration section.
This means for example that instead of having to define `develop` specs in the
`spack.yaml`, the environment can `include:` another `develop.yaml` configuration
which specifies which specs should be developed in the environment.

This change is not expected to be disruptive given that existing environment `spack.yaml`
files will conform to the new schema.

(Update 11/28/2023) I have implemented the `develop`/`undevelop` commands in terms
of more-generic modification functions added to the `config` module: `change_or_add`
and `update_all`. It is assumed that the semantics added here (described in 11/18 update)
would be desirable to extend to other config update actions (e.g. adding compilers, 
changing package requirements, adding mirrors).

(Update 11/18/2023) I have updated this such that `spack develop`, and
`spack undevelop` to potentially modify all writable scopes, like 
https://github.com/spack/spack/pull/41147. https://github.com/spack/spack/pull/35307
will be useful for modifying included scopes, but generally speaking specifying a 
`--scope` will not be required for `spack develop`: `spack develop` will add new 
develop specs to whatever scope already has develop specs defined, or to the
highest-priority writable scope (which should be the env scope).

TODOs:

- [x] If you `spack undevelop` a package which is mentioned at multiple layers of
      configuration, then currently this would only modify one of them. That's not
      technically a new issue (has always existed for configuration modification), but
      may be confusing to users when presented via an interface other than `spack config set`
- [x] Need to add (or confirm) the ability to modify individual config files by providing
      a path (rather than using a scope identifier as a key to retrieve associated config).
- [x] `spack develop` adds new develop specs to the scope that defines them
      (potentially skipping higher priority scopes to e.g. augment included scope files)

---------

Co-authored-by: scheibelp <scheibelp@users.noreply.github.com>
Co-authored-by: Todd Gamblin <tgamblin@llnl.gov>

1 files changed, 3 insertions, 3 deletions

diff --git a/share/spack/spack-completion.fish b/share/spack/spack-completion.fish
index 090f725fa1..a05cb6c658 100755
--- a/share/spack/spack-completion.fish
+++ b/share/spack/spack-completion.fish
@@ -1173,19 +1173,19 @@ complete -c spack -n '__fish_spack_using_command config' -l scope -r -d 'configu
 
 # spack config get
 set -g __fish_spack_optspecs_spack_config_get h/help
-complete -c spack -n '__fish_spack_using_command_pos 0 config get' -f -a 'bootstrap cdash ci compilers concretizer config definitions mirrors modules packages repos upstreams'
+complete -c spack -n '__fish_spack_using_command_pos 0 config get' -f -a 'bootstrap cdash ci compilers concretizer config definitions develop mirrors modules packages repos upstreams'
 complete -c spack -n '__fish_spack_using_command config get' -s h -l help -f -a help
 complete -c spack -n '__fish_spack_using_command config get' -s h -l help -d 'show this help message and exit'
 
 # spack config blame
 set -g __fish_spack_optspecs_spack_config_blame h/help
-complete -c spack -n '__fish_spack_using_command_pos 0 config blame' -f -a 'bootstrap cdash ci compilers concretizer config definitions mirrors modules packages repos upstreams'
+complete -c spack -n '__fish_spack_using_command_pos 0 config blame' -f -a 'bootstrap cdash ci compilers concretizer config definitions develop mirrors modules packages repos upstreams'
 complete -c spack -n '__fish_spack_using_command config blame' -s h -l help -f -a help
 complete -c spack -n '__fish_spack_using_command config blame' -s h -l help -d 'show this help message and exit'
 
 # spack config edit
 set -g __fish_spack_optspecs_spack_config_edit h/help print-file
-complete -c spack -n '__fish_spack_using_command_pos 0 config edit' -f -a 'bootstrap cdash ci compilers concretizer config definitions mirrors modules packages repos upstreams'
+complete -c spack -n '__fish_spack_using_command_pos 0 config edit' -f -a 'bootstrap cdash ci compilers concretizer config definitions develop mirrors modules packages repos upstreams'
 complete -c spack -n '__fish_spack_using_command config edit' -s h -l help -f -a help
 complete -c spack -n '__fish_spack_using_command config edit' -s h -l help -d 'show this help message and exit'
 complete -c spack -n '__fish_spack_using_command config edit' -l print-file -f -a print_file