Incompatible Target Skipping breaks rules with custom providers

[philsc]

Description of the problem / feature request:

Consider the following Starlark rule:

DummyProvider = provider()

def _dummy_rule_impl(ctx):
    return [DummyProvider()]

dummy_rule = rule(
    implementation = _dummy_rule_impl,
    attrs = {
        "deps": attr.label_list(providers=[DummyProvider]),
    },
)

If you instantiate it like this:

load(":rules.bzl", "dummy_rule")

dummy_rule(
    name = "dummy1",
    target_compatible_with = ["@platforms//:incompatible"],
)

dummy_rule(
    name = "dummy2",
    deps = [
        ":dummy1",
    ],
)

then building fails with:

ERROR: /home/phil/.cache/bazel/_bazel_phil/b4868b516be4e3bea4d221937a55ced4/sandbox/linux-sandbox/2572/execroot/io_bazel/_tmp/c749fd38ac9a4ad6bd41e9653bbceab5/workspace/target_skipping/BUILD:112:11: in deps attribute of dummy_rule rule //target_skipping:dummy2: '//target_skipping:dummy1' does not have mandatory providers: 'DummyProvider'

This occurs because the incompatible target is assigned an IncompatiblePlatformProvider and not a DummyProvider.

The same thing happens when using Python targets:

ERROR: /home/phil/repos/971-Robot-Code/frc971/control_loops/python/BUILD:189:11: in deps attribute of py_library rule //frc971/control_loops/python:basic_window: '@python_gtk//:python_gtk' does not have mandatory providers: 'py' or 'PyInfo'

A quick hack to fix this is:

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
index 78ee802789..e094b7b529 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
@@ -43,6 +43,7 @@ import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.Artifact.SpecialArtifact;
 import com.google.devtools.build.lib.actions.ArtifactRoot;
 import com.google.devtools.build.lib.analysis.AliasProvider.TargetMode;
+import com.google.devtools.build.lib.analysis.IncompatiblePlatformProvider;
 import com.google.devtools.build.lib.analysis.actions.ActionConstructionContext;
 import com.google.devtools.build.lib.analysis.buildinfo.BuildInfoKey;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
@@ -2292,6 +2293,10 @@ public final class RuleContext extends TargetContext
         return true;
       }

+      if (prerequisite.getConfiguredTarget().getProvider(IncompatiblePlatformProvider.class) != null) {
+        return true;
+      }
+
       unfulfilledRequirements.add(
           String.format(
               "'%s' does not have mandatory providers: %s",

What operating system are you running Bazel on?

x86_64 Linux

What's the output of bazel info release?

Running off latest master (d0efd7b).

If bazel info release returns "development version" or "(@non-git)", tell us how you built Bazel.

$ bazel build -c opt //src:bazel

[philsc]

I'll try to figure out what a less hacky way of addressing this is.

/cc @gregestren , @AustinSchuh

[philsc]

Hmm. I discovered another bug while testing #12560. A filegroup that depends on an incompatible target is itself not incompatible.

[philsc]

Hmm. I discovered another bug while testing #12560. A filegroup that depends on an incompatible target is itself not incompatible.

Filed #12582 for this.

[philsc]

There may also be something similar going on with the checks for the extensions.

ERROR: /home/phil/repos/971-Robot-Code/third_party/gmp/BUILD:481:11: in srcs attribute of cc_library rule //third_party/gmp:mpn_core: '//third_party/gmp:dump' does not produce any cc_library srcs files (expected .cc, .cpp, .cxx, .c++, .C, .cu, .cl, .c, .h, .hh, .hpp, .ipp, .hxx, .h++, .inc, .inl, .tlh, .tli, .H, .tcc, .S, .s, .asm, .a, .lib, .pic.a, .lo,
 .lo.lib, .pic.lo, .so, .dylib, .dll, .o, .obj or .pic.o)