warnings for local-recipes-index

[memsharded]

No description provided.

[jcar87]

I would probably tweak wording to make it more "generic" in terms of explaining the pitfalls, but more specific in terms of what happens with Conan Center.

Some suggestions:

• Mention explicity that the git repository at conan-center-index's main purpose is to feed into the conancenter remote, and the ability to use it as a local-recipes-index is not a goal.
• Remove "building binaries from a private conan-center-index fork" from the paragraph above - and instead mention something like "test changes in multiple recipes together without exporting them before hand" (which from memory, I believe was one of the intended uses of local-recipes-index when it comes to operating a fork)
• Clarify, very explicitly, that unlike a remote Conan server, local-recipes-index does not support recipe revisions, but instead the current branch is a snapshot of all versions and revisions visible. This is already mentioned down below, but may be good to mention it here again
• Reword, that when using a local-recipes-index with a fork of conan-center-index, users must be careful in the two following scenarios:
  • bringing changes from upstream (git pull, git merge master, git rebase master etc) - because versions they rely on may no longer be exportable from master. Here the best mitigation is just to ensure the versions needed by the user are always in the repo, for example, they can always add their versions to a different subfolder (e.g. something other than "all") - which will minimise merge conflicts as the only potential change is "config.yml" in this scenario
• when using the conancenter remote alongside local-recipes-index, you have two repositories that potentially export the same versions. This may be intentional or not - users need exercise care.

[jcar87]

Since it is not possible to upload binary packages to a remote without also uploading the recipes, I would probably just leave this whole section out, as it essential boils down to "if you need binaries, you need a server" therefore, using local-recipes-index AND needing to configure a remote, it is not entirely clear in which scenario local-recipes-index offers an advantage.