refactor: move all re-exports to private/reexports.bzl (#739)

Author: mattem

python/defs.bzl

@@ -12,35 +12,28 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Core rules for building Python projects.
-
-Currently the definitions here are re-exports of the native rules, "blessed" to
-work under `--incompatible_load_python_rules_from_bzl`. As the native rules get
-migrated to Starlark, their implementations will be moved here.
+"""
+Core rules for building Python projects.
 """
 
 load("@bazel_tools//tools/python:srcs_version.bzl", _find_requirements = "find_requirements")
 load("@bazel_tools//tools/python:toolchain.bzl", _py_runtime_pair = "py_runtime_pair")
-load("//python/private:reexports.bzl", "internal_PyInfo", "internal_PyRuntimeInfo")
+load(
+    "//python/private:reexports.bzl",
+    "internal_PyInfo",
+    "internal_PyRuntimeInfo",
+    _py_binary = "py_binary",
+    _py_library = "py_library",
+    _py_runtime = "py_runtime",
+    _py_test = "py_test",
+)
 
 # Exports of native-defined providers.
 
 PyInfo = internal_PyInfo
 
 PyRuntimeInfo = internal_PyRuntimeInfo
 
-# The implementation of the macros and tagging mechanism follows the example
-# set by rules_cc and rules_java.
-
-_MIGRATION_TAG = "__PYTHON_RULES_MIGRATION_DO_NOT_USE_WILL_BREAK__"
-
-def _add_tags(attrs):
-    if "tags" in attrs and attrs["tags"] != None:
-        attrs["tags"] = attrs["tags"] + [_MIGRATION_TAG]
-    else:
-        attrs["tags"] = [_MIGRATION_TAG]
-    return attrs
-
 def _current_py_toolchain_impl(ctx):
     toolchain = ctx.toolchains[ctx.attr._toolchain]
 
@@ -84,36 +77,6 @@ current_py_toolchain = rule(
     ],
 )
 
-def py_library(**attrs):
-    """See the Bazel core [py_library](https://docs.bazel.build/versions/master/be/python.html#py_library) documentation.
-
-    Args:
-      **attrs: Rule attributes
-    """
-
-    # buildifier: disable=native-python
-    native.py_library(**_add_tags(attrs))
-
-def py_binary(**attrs):
-    """See the Bazel core [py_binary](https://docs.bazel.build/versions/master/be/python.html#py_binary) documentation.
-
-    Args:
-      **attrs: Rule attributes
-    """
-
-    # buildifier: disable=native-python
-    native.py_binary(**_add_tags(attrs))
-
-def py_test(**attrs):
-    """See the Bazel core [py_test](https://docs.bazel.build/versions/master/be/python.html#py_test) documentation.
-
-    Args:
-      **attrs: Rule attributes
-    """
-
-    # buildifier: disable=native-python
-    native.py_test(**_add_tags(attrs))
-
 def _py_import_impl(ctx):
     # See https://github.com/bazelbuild/bazel/blob/0.24.0/src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPythonSemantics.java#L104 .
     import_paths = [
@@ -164,18 +127,16 @@ py_import = rule(
     },
 )
 
-def py_runtime(**attrs):
-    """See the Bazel core [py_runtime](https://docs.bazel.build/versions/master/be/python.html#py_runtime) documentation.
-
-    Args:
-      **attrs: Rule attributes
-    """
-
-    # buildifier: disable=native-python
-    native.py_runtime(**_add_tags(attrs))
-
 # Re-exports of Starlark-defined symbols in @bazel_tools//tools/python.
 
 py_runtime_pair = _py_runtime_pair
 
 find_requirements = _find_requirements
+
+py_library = _py_library
+
+py_binary = _py_binary
+
+py_test = _py_test
+
+py_runtime = _py_runtime

python/private/reexports.bzl

@@ -14,6 +14,10 @@
 
 """Internal re-exports of built-in symbols.
 
+Currently the definitions here are re-exports of the native rules, "blessed" to
+work under `--incompatible_load_python_rules_from_bzl`. As the native rules get
+migrated to Starlark, their implementations will be removed from here.
+
 We want to re-export a built-in symbol as if it were defined in a Starlark
 file, so that users can for instance do:
 
@@ -33,6 +37,18 @@ different name. Then we can load it from defs.bzl and export it there under
 the original name.
 """
 
+# The implementation of the macros and tagging mechanism follows the example
+# set by rules_cc and rules_java.
+
+_MIGRATION_TAG = "__PYTHON_RULES_MIGRATION_DO_NOT_USE_WILL_BREAK__"
+
+def _add_tags(attrs):
+    if "tags" in attrs and attrs["tags"] != None:
+        attrs["tags"] = attrs["tags"] + [_MIGRATION_TAG]
+    else:
+        attrs["tags"] = [_MIGRATION_TAG]
+    return attrs
+
 # Don't use underscore prefix, since that would make the symbol local to this
 # file only. Use a non-conventional name to emphasize that this is not a public
 # symbol.
@@ -41,3 +57,43 @@ internal_PyInfo = PyInfo
 
 # buildifier: disable=name-conventions
 internal_PyRuntimeInfo = PyRuntimeInfo
+
+def py_library(**attrs):
+    """See the Bazel core [py_library](https://docs.bazel.build/versions/master/be/python.html#py_library) documentation.
+
+    Args:
+      **attrs: Rule attributes
+    """
+
+    # buildifier: disable=native-python
+    native.py_library(**_add_tags(attrs))
+
+def py_binary(**attrs):
+    """See the Bazel core [py_binary](https://docs.bazel.build/versions/master/be/python.html#py_binary) documentation.
+
+    Args:
+      **attrs: Rule attributes
+    """
+
+    # buildifier: disable=native-python
+    native.py_binary(**_add_tags(attrs))
+
+def py_test(**attrs):
+    """See the Bazel core [py_test](https://docs.bazel.build/versions/master/be/python.html#py_test) documentation.
+
+    Args:
+      **attrs: Rule attributes
+    """
+
+    # buildifier: disable=native-python
+    native.py_test(**_add_tags(attrs))
+
+def py_runtime(**attrs):
+    """See the Bazel core [py_runtime](https://docs.bazel.build/versions/master/be/python.html#py_runtime) documentation.
+
+    Args:
+      **attrs: Rule attributes
+    """
+
+    # buildifier: disable=native-python
+    native.py_runtime(**_add_tags(attrs))