fix(PyRuntimeInfo): use builtin PyRuntimeInfo unless pystar is enable…

…d. (#1748)

This fixes the bug where the PyRuntimeInfo symbol rules_python exported
wasn't matching the provider identity that `py_binary` actually
provided.

The basic problem was, when pystar is disabled:
 * PyRuntimeInfo is the rules_python defined provider
* py_binary is `native.py_binary`, which provides only the builtin
PyRuntimeInfo provider.

Thus, when users loaded the rules_python PyRuntimeInfo symbol, it was
referring to a provider that the underlying py_binary didn't actually
provide. Pystar is always disabled on Bazel 6.4,
and enabling it for Bazel 7 will happen eminently.

This typically showed up when users had a custom rule with an attribute
definition that used the rules_python PyRuntimeInfo.

To fix, only use the rules_python define PyRuntimeInfo if pystar is
enabled. This ensures the providers the underlying rules are providing
match the symbols that rules_python is exported.

* Also fixes `py_binary` and `py_test` to also return the builtin
PyRuntimeInfo. This
should make the transition from the builtin symbols to the rules_python
symbols a bit
  easier.

Fixes #1732

CHANGELOG.md

@@ -48,6 +48,11 @@ A brief description of the categories of changes:
 * (toolchain) Changed the `host_toolchain` to symlink all files to support
   Windows host environments without symlink support.
 
+* (PyRuntimeInfo) Switch back to builtin PyRuntimeInfo for Bazel 6.4 and when
+  pystar is disabled. This fixes an error about `target ... does not have ...
+  PyRuntimeInfo`.
+  ([#1732](https://github.com/bazelbuild/rules_python/issues/1732))
+
 ### Added
 
 * (py_wheel) Added `requires_file` and `extra_requires_files` attributes.

python/private/common/py_executable.bzl

@@ -14,6 +14,7 @@
 """Common functionality between test/binary executables."""
 
 load("@bazel_skylib//lib:dicts.bzl", "dicts")
+load("//python/private:reexports.bzl", "BuiltinPyRuntimeInfo")
 load(
     ":attributes.bzl",
     "AGNOSTIC_EXECUTABLE_ATTRS",
@@ -771,7 +772,28 @@ def _create_providers(
     # TODO(b/265840007): Make this non-conditional once Google enables
     # --incompatible_use_python_toolchains.
     if runtime_details.toolchain_runtime:
-        providers.append(runtime_details.toolchain_runtime)
+        py_runtime_info = runtime_details.toolchain_runtime
+        providers.append(py_runtime_info)
+
+        # Re-add the builtin PyRuntimeInfo for compatibility to make
+        # transitioning easier, but only if it isn't already added because
+        # returning the same provider type multiple times is an error.
+        # NOTE: The PyRuntimeInfo from the toolchain could be a rules_python
+        # PyRuntimeInfo or a builtin PyRuntimeInfo -- a user could have used the
+        # builtin py_runtime rule or defined their own. We can't directly detect
+        # the type of the provider object, but the rules_python PyRuntimeInfo
+        # object has an extra attribute that the builtin one doesn't.
+        if hasattr(py_runtime_info, "interpreter_version_info"):
+            providers.append(BuiltinPyRuntimeInfo(
+                interpreter_path = py_runtime_info.interpreter_path,
+                interpreter = py_runtime_info.interpreter,
+                files = py_runtime_info.files,
+                coverage_tool = py_runtime_info.coverage_tool,
+                coverage_files = py_runtime_info.coverage_files,
+                python_version = py_runtime_info.python_version,
+                stub_shebang = py_runtime_info.stub_shebang,
+                bootstrap_template = py_runtime_info.bootstrap_template,
+            ))
 
     # TODO(b/163083591): Remove the PyCcLinkParamsProvider once binaries-in-deps
     # are cleaned up.

python/py_runtime_info.bzl

@@ -14,8 +14,8 @@
 
 """Public entry point for PyRuntimeInfo."""
 
+load("@rules_python_internal//:rules_python_config.bzl", "config")
 load("//python/private:reexports.bzl", "BuiltinPyRuntimeInfo")
-load("//python/private:util.bzl", "IS_BAZEL_6_OR_HIGHER")
 load("//python/private/common:providers.bzl", _starlark_PyRuntimeInfo = "PyRuntimeInfo")
 
-PyRuntimeInfo = _starlark_PyRuntimeInfo if IS_BAZEL_6_OR_HIGHER else BuiltinPyRuntimeInfo
+PyRuntimeInfo = _starlark_PyRuntimeInfo if config.enable_pystar else BuiltinPyRuntimeInfo

tests/base_rules/py_executable_base_tests.bzl

@@ -13,6 +13,7 @@
 # limitations under the License.
 """Tests common to py_binary and py_test (executable rules)."""
 
+load("@rules_python//python:py_runtime_info.bzl", RulesPythonPyRuntimeInfo = "PyRuntimeInfo")
 load("@rules_python_internal//:rules_python_config.bzl", rp_config = "config")
 load("@rules_testing//lib:analysis_test.bzl", "analysis_test")
 load("@rules_testing//lib:truth.bzl", "matching")
@@ -21,6 +22,8 @@ load("//tests/base_rules:base_tests.bzl", "create_base_tests")
 load("//tests/base_rules:util.bzl", "WINDOWS_ATTR", pt_util = "util")
 load("//tests/support:test_platforms.bzl", "WINDOWS")
 
+_BuiltinPyRuntimeInfo = PyRuntimeInfo
+
 _tests = []
 
 def _test_basic_windows(name, config):
@@ -275,6 +278,28 @@ def _test_name_cannot_end_in_py_impl(env, target):
         matching.str_matches("name must not end in*.py"),
     )
 
+def _test_py_runtime_info_provided(name, config):
+    rt_util.helper_target(
+        config.rule,
+        name = name + "_subject",
+        srcs = [name + "_subject.py"],
+    )
+    analysis_test(
+        name = name,
+        impl = _test_py_runtime_info_provided_impl,
+        target = name + "_subject",
+    )
+
+def _test_py_runtime_info_provided_impl(env, target):
+    # Make sure that the rules_python loaded symbol is provided.
+    env.expect.that_target(target).has_provider(RulesPythonPyRuntimeInfo)
+
+    # For compatibility during the transition, the builtin PyRuntimeInfo should
+    # also be provided.
+    env.expect.that_target(target).has_provider(_BuiltinPyRuntimeInfo)
+
+_tests.append(_test_py_runtime_info_provided)
+
 # Can't test this -- mandatory validation happens before analysis test
 # can intercept it
 # TODO(#1069): Once re-implemented in Starlark, modify rule logic to make this