Fix empty buildinfo when using conan export-package

[getrostt]

When building a conan package using conan export-pkg, the resulting build-info when running conan art:build-info create is empty. This is caused by an unconditional removal of the 1st graph node in the resulting json file.

This fix only removes the 1st node when it is a ref of type conanfile.

[CLAassistant]

All committers have signed the CLA.

[memsharded]

Thanks very much for your contribution @getrostt

Adding @czoido so he might be able to help checking the potential issue (maybe the way to avoid it is checking the existing of the path field?

[memsharded]

I am concern about cases where the consumer might have defined a name and version, so the ref might not be "conanfile", but the actual name/version.

Maybe it would be necessary to add a test for that scenario.

[getrostt]

I tried to replay the scenario on the commandline using the following commands:

conan new cmake_lib -d name=mypkg -d version=1.0 --force
conan create . --format json -tf='' -s build_type=Release > create_release.json

That results in the following create_release.json (I only pasted the 1st lines):

{
    "graph": {
        "nodes": {
            "0": {
                "ref": "conanfile",
                "id": "0",

Is this the behavior you were thinking of for a test?

[czoido]

May we remove the node 0 in the case that "prev": null to differentiate both cases @memsharded ?

[czoido]

Hi @getrostt,
Thanks a lot for the contribution. I proposed some changes there to consider all cases. I'll have to open a separate PR for this because we can only run tests marked as requires_credentials if they run from a branch from the repo not from forks. I'll cherry-pick your changes so you still appear as contributor.

[czoido]

Closing this one in favor of #157