[build2] Failing to build packages in remote git repositories

[Klaim - Joël Lamotte]

Hi Karen,

On 16 July 2018 at 21:54, Karen Arutyunov <karen at codesynthesis.com> wrote:
> Hi Joël,
>
>> Am I missing something?
>
> Yeah, it seems that you miss '#master' URL fragment:
>
> $ bpkg build https://github.com/Klaim/test-build2-package-repo.git#master
>
> $ bpkg build kikoo at ../test-build2-package-repo#master
>
> The man page says:
>
> By default, only advertised tags in the refs/tags/v* form where the part
> after v is also a valid standard version (b#module-version) are considered
> to be sources of useful package versions. These commits normally correspond
> to released versions and are called the default set.
>

That explains it! Thanks!
I read that before but didn't link it to that issue in my mind.

In this case it seems that the message "nothing to build" is not very
helpful as it doesn't say why nothing was found (or what was looked
for).
After all, I attempted to explicitely "build" something, so the tools
can assume that it was my attempt and some info is missing.

Suggestion: make the message "Nothing to build:
<explains-why-depending-on-the-kind-of-uri>"

For git or maybe any potential kind of repository, I suggest
"No refs/tags/v* tags found matching the request, not branch specified."
for the why.

Side note: it looks a lot like the situation in C++ compilation where
the compiler says it didn't found an overload
matching the arguments, but didn't say what it did. Now all compilers
give more info because it's helpful for the developer.
I'm pointing this because there might be interesting insights in error
reporting in the way the compilers evolved that could help build2
reports.
Although it's not a priority, a pass on the reports might help a lot
learning build2.

In any ways I can continue my experiments then, thanks again.

A. Joël Lamotte