Implement test_package --build-test=missing for full control of test_package deps

[memsharded]

Changelog: Feature: conan create --build-test=missing new argument to control what is being built as dependencies of the test_package folder.
Docs: conan-io/docs#3336

Close #14314
Close #14352

[jcar87]

I have tested this flag with a test_package like this:

    def requirements(self):
        self.requires(self.tested_reference_str)

    def build_requirements(self):
        self.tool_requires(self.tested_reference_str)

while invoking conan create in a way that results in both of these being satisfied by two different package IDs of the same reference, and this flag works perfectly fine and builds the missing reference.

However I still find it a bit counter intuitive, or perhaps it may need to be better documented

conan create . --build=missing will fail for the code below if this results in two different package IDs being required:

    def requirements(self):
        self.requires(self.tested_reference_str)

    def build_requirements(self):
        self.tool_requires(self.tested_reference_str)

But the following scenario, where:

• foobar/123 is exported
• it is NOT a dependency of self.tested_reference_str and only appears as a requirement of the test package
• there is currently no package generated for it

    def requirements(self):
        self.requires(self.tested_reference_str)
        self.requires("foobar/123")

In this scenario,

conan create . --build=missing

will currently succeed (even before this PR), and will generate the missing package for foobar/1.2.3. So what is difficult to reason, on documentation alone, is why --build=missing works for some of the references required by the test package, but specifically not for the one being created. I am aware why, but perhaps it needs a clarification in the documentation.

This can create confusion as to why --build-test=missing does that --build=missing doesn't, when passed as an argument to Conan create. I only see two useful scenarios:

• when one knows beforehand that there are multiple requirements on self.tested_reference_str
  and perhaps the more unusual but also valid:
• when one wants conan create to force a build of the reference, rather than reuse an existing package, but still wants it to build any missing dependencies of the test_package

[memsharded]

Thanks very much for the thorough review and testing @jcar87

I think the self.requires("foobar/123") behavior might be an overlook, you are right, it doesn't look like the most intuitive behavior, I will add some tests and check it.

[memsharded]

I think it is working fine, adding an extra test to the PR that validates it:

    def test_build_test_package_dep(self):
        c = TestClient()
        c.save({"dep/conanfile.py": GenConanfile("dep", "0.1"),
                "pkg/conanfile.py": GenConanfile("pkg", "0.1"),
                "pkg/test_package/conanfile.py": GenConanfile().with_requires("dep/0.1")
                                                               .with_test("pass")})
        c.run("export dep")
        c.run("create pkg --build=missing", assert_error=True)
        c.assert_listed_binary({"pkg/0.1": ("da39a3ee5e6b4b0d3255bfef95601890afd80709", "Build")})
        c.assert_listed_binary({"dep/0.1": ("da39a3ee5e6b4b0d3255bfef95601890afd80709", "Missing"),
                                "pkg/0.1": ("da39a3ee5e6b4b0d3255bfef95601890afd80709", "Cache")},
                               test_package=True)

This works, and raise an error because the binary is missing.
Can you please double check? Is it possible that you got the binary in the cache built in a previous command?

[jcar87]

LGTM!

I think the behaviour changes makes sense, that is --build=missing now applies only to the graph of the reference being created, and --build-test missing applies to the graph of the test_package, which may contain additional references (if the test package has them).

I think this makes sense with the premise that conan create has a premise where for the tested reference it should only build what is requested