fix(pypi): expose pypi packages only common to all python versions

CHANGELOG.md

@@ -91,6 +91,8 @@ END_UNRELEASED_TEMPLATE
 * Multi-line python imports (e.g. with escaped newlines) are now correctly processed by Gazelle.
 * (toolchains) `local_runtime_repo` works with multiarch Debian with Python 3.8
   ([#3099](https://github.com/bazel-contrib/rules_python/issues/3099)).
+* (pypi) Expose pypi packages only common to all Python versions in `all_requirements`
+  ([#2921](https://github.com/bazel-contrib/rules_python/issues/2921)).
 
 {#v0-0-0-added}
 ### Added

python/private/pypi/extension.bzl

@@ -601,7 +601,15 @@ You cannot use both the additive_build_content and additive_build_content_file a
             extra_aliases.setdefault(hub_name, {})
             for whl_name, aliases in out.extra_aliases.items():
                 extra_aliases[hub_name].setdefault(whl_name, {}).update(aliases)
-            exposed_packages.setdefault(hub_name, {}).update(out.exposed_packages)
+            if hub_name not in exposed_packages:
+                exposed_packages[hub_name] = out.exposed_packages
+            else:
+                intersection = {}
+                for pkg in out.exposed_packages:
+                    if pkg not in exposed_packages[hub_name]:
+                        continue
+                    intersection[pkg] = None
+                exposed_packages[hub_name] = intersection
             whl_libraries.update(out.whl_libraries)
 
             # TODO @aignas 2024-04-05: how do we support different requirement

tests/pypi/extension/extension_tests.bzl

@@ -285,6 +285,104 @@ def _test_simple_multiple_requirements(env):
 
 _tests.append(_test_simple_multiple_requirements)
 
+def _test_simple_multiple_python_versions(env):
+    pypi = _parse_modules(
+        env,
+        module_ctx = _mock_mctx(
+            _mod(
+                name = "rules_python",
+                parse = [
+                    _parse(
+                        hub_name = "pypi",
+                        python_version = "3.15",
+                        requirements_lock = "requirements_3_15.txt",
+                    ),
+                    _parse(
+                        hub_name = "pypi",
+                        python_version = "3.16",
+                        requirements_lock = "requirements_3_16.txt",
+                    ),
+                ],
+            ),
+            read = lambda x: {
+                "requirements_3_15.txt": """
+simple==0.0.1 --hash=sha256:deadbeef
+old-package==0.0.1 --hash=sha256:deadbaaf
+""",
+                "requirements_3_16.txt": """
+simple==0.0.2 --hash=sha256:deadb00f
+new-package==0.0.1 --hash=sha256:deadb00f2
+""",
+            }[x],
+        ),
+        available_interpreters = {
+            "python_3_15_host": "unit_test_interpreter_target",
+            "python_3_16_host": "unit_test_interpreter_target",
+        },
+        minor_mapping = {
+            "3.15": "3.15.19",
+            "3.16": "3.16.9",
+        },
+    )
+
+    pypi.exposed_packages().contains_exactly({"pypi": ["simple"]})
+    pypi.hub_group_map().contains_exactly({"pypi": {}})
+    pypi.hub_whl_map().contains_exactly({
+        "pypi": {
+            "new_package": {
+                "pypi_316_new_package": [
+                    whl_config_setting(
+                        version = "3.16",
+                    ),
+                ],
+            },
+            "old_package": {
+                "pypi_315_old_package": [
+                    whl_config_setting(
+                        version = "3.15",
+                    ),
+                ],
+            },
+            "simple": {
+                "pypi_315_simple": [
+                    whl_config_setting(
+                        version = "3.15",
+                    ),
+                ],
+                "pypi_316_simple": [
+                    whl_config_setting(
+                        version = "3.16",
+                    ),
+                ],
+            },
+        },
+    })
+    pypi.whl_libraries().contains_exactly({
+        "pypi_315_old_package": {
+            "dep_template": "@pypi//{name}:{target}",
+            "python_interpreter_target": "unit_test_interpreter_target",
+            "requirement": "old-package==0.0.1 --hash=sha256:deadbaaf",
+        },
+        "pypi_315_simple": {
+            "dep_template": "@pypi//{name}:{target}",
+            "python_interpreter_target": "unit_test_interpreter_target",
+            "requirement": "simple==0.0.1 --hash=sha256:deadbeef",
+        },
+        "pypi_316_new_package": {
+            "dep_template": "@pypi//{name}:{target}",
+            "python_interpreter_target": "unit_test_interpreter_target",
+            "requirement": "new-package==0.0.1 --hash=sha256:deadb00f2",
+        },
+        "pypi_316_simple": {
+            "dep_template": "@pypi//{name}:{target}",
+            "python_interpreter_target": "unit_test_interpreter_target",
+            "requirement": "simple==0.0.2 --hash=sha256:deadb00f",
+        },
+    })
+    pypi.whl_mods().contains_exactly({})
+
+_tests.append(_test_simple_multiple_python_versions)
+
 def _test_simple_with_markers(env):
     pypi = _parse_modules(
         env,