feat: support Bazel 6 (#266)

aspect-build · Feb 21, 2024 · ddc4f3b · ddc4f3b
1 parent 76e1908
commit ddc4f3b
Show file tree

Hide file tree

Showing 9 changed files with 86 additions and 20 deletions.
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
@@ -21,6 +21,5 @@ jobs:
     uses: bazel-contrib/.github/.github/workflows/bazel.yaml@e76b9e5a1d91256e06b097c4470a22263969600b
     with:
       folders: '[".", "e2e/smoke"]'
-      # TODO: make the root folder work with bzlmod
-      # MAYBE: allow usage from Bazel 6 as well
-      exclude: '[{"bazelversion": "6.4.0"}, {"folder": ".", "bzlmodEnabled": true}]'
+      # TODO(alex): switch the root folder to bzlmod
+      exclude: '[{"folder": ".", "bazelversion": "6.4.0"}, {"folder": ".", "bzlmodEnabled": true}]'
diff --git a/e2e/smoke/.bazelrc b/e2e/smoke/.bazelrc
@@ -0,0 +1,2 @@
+# Under Bazel 7 or later, this flag is ignored as the PyRuntimeInfo gives this information.
+common --@aspect_rules_py//py:interpreter_version=3.9.18
diff --git a/py/BUILD.bazel b/py/BUILD.bazel
@@ -1,8 +1,18 @@
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
+load("@bazel_skylib//rules:common_settings.bzl", "string_flag")
 
 # For stardoc to reference the files
 exports_files(["defs.bzl"])
 
+# For Bazel 6.x compatibility, since 
+# PyRuntimeInfo shipped only with Bazel 7
+# Users can set, e.g. --@aspect_rules_py//py:interpreter_version=3.9.18
+string_flag(
+    name = "interpreter_version",
+    build_setting_default = "",
+    visibility = ["//visibility:public"],
+)
+
 bzl_library(
     name = "repositories",
     srcs = ["repositories.bzl"],

diff --git a/py/private/BUILD.bazel b/py/private/BUILD.bazel
@@ -62,7 +62,10 @@ bzl_library(
     name = "py_semantics",
     srcs = ["py_semantics.bzl"],
     visibility = ["//py:__subpackages__"],
-    deps = ["//py/private/toolchain:types"],
+    deps = [
+        "//py/private/toolchain:types",
+        "@bazel_skylib//rules:common_settings",
+    ],
 )
 
 bzl_library(

diff --git a/py/private/py_binary.bzl b/py/private/py_binary.bzl
@@ -74,15 +74,15 @@ def _py_binary_rule_impl(ctx):
             "{{ARG_PYTHON}}": to_rlocation_path(ctx, py_toolchain.python),
             "{{ARG_VENV_NAME}}": ".{}.venv".format(ctx.attr.name),
             "{{ARG_VENV_PYTHON_VERSION}}": "{}.{}.{}".format(
-                py_toolchain.toolchain.interpreter_version_info.major,
-                py_toolchain.toolchain.interpreter_version_info.minor,
-                py_toolchain.toolchain.interpreter_version_info.micro,
+                py_toolchain.interpreter_version_info.major,
+                py_toolchain.interpreter_version_info.minor,
+                py_toolchain.interpreter_version_info.micro,
             ),
             "{{ARG_PTH_FILE}}": to_rlocation_path(ctx, site_packages_pth_file),
             "{{ENTRYPOINT}}": to_rlocation_path(ctx, ctx.file.main),
             "{{PYTHON_ENV}}": "\n".join(_dict_to_exports(env)).strip(),
             "{{EXEC_PYTHON_BIN}}": "python{}".format(
-                py_toolchain.toolchain.interpreter_version_info.major,
+                py_toolchain.interpreter_version_info.major,
             ),
         },
         is_executable = True,
@@ -146,6 +146,10 @@ _attrs = dict({
     "_runfiles_lib": attr.label(
         default = "@bazel_tools//tools/bash/runfiles",
     ),
+    # NB: this is read by _resolve_toolchain in py_semantics.
+    "_interpreter_version_flag": attr.label(
+        default = "//py:interpreter_version",
+    ),
 })
 
 _attrs.update(**_py_library.attrs)

diff --git a/py/private/py_semantics.bzl b/py/private/py_semantics.bzl
@@ -1,8 +1,32 @@
 """Functions to determine which Python toolchain to use"""
 
 load("//py/private/toolchain:types.bzl", "PY_TOOLCHAIN")
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 
-_INTERPRETER_FLAGS = ["-B", "-I"]
+_INTERPRETER_FLAGS = [
+    # -B     Don't write .pyc files on import. See also PYTHONDONTWRITEBYTECODE.
+    "-B",
+    # -I     Run Python in isolated mode. This also implies -E and -s.
+    #        In isolated mode sys.path contains neither the script's directory nor the user's site-packages directory.
+    #        All PYTHON* environment variables are ignored, too.
+    #        Further restrictions may be imposed to prevent the user from injecting malicious code.
+    "-I",
+]
+
+_MUST_SET_INTERPRETER_VERSION_FLAG = """\
+ERROR: Prior to Bazel 7.x, the python interpreter version must be explicitly provided.
+
+For example in `.bazelrc` with Bazel 6.4, add
+        
+    common --@aspect_rules_py//py:interpreter_version=3.9.18
+
+Bazel 6.3 and earlier didn't handle the `common` verb for custom flags.
+Repeat the flag to avoid discarding the analysis cache:
+
+    build --@aspect_rules_py//py:interpreter_version=3.9.18
+    fetch --@aspect_rules_py//py:interpreter_version=3.9.18
+    query --@aspect_rules_py//py:interpreter_version=3.9.18
+"""
 
 def _resolve_toolchain(ctx):
     """Resolves the Python toolchain to a simple struct.
@@ -36,10 +60,27 @@ def _resolve_toolchain(ctx):
         files = depset([])
         uses_interpreter_path = True
 
+    # Bazel 7 has this field on the PyRuntimeInfo
+    if "interpreter_version_info" in dir(py3_toolchain):
+        interpreter_version_info = py3_toolchain.interpreter_version_info
+    elif ctx.attr._interpreter_version_flag[BuildSettingInfo].value:
+        # Back-compat for Bazel 6.
+        # Same code as rules_python:
+        # https://github.com/bazelbuild/rules_python/blob/76f1c76f60ccb536d3b3e2c9f023d8063f40bcd5/python/repositories.bzl#L109
+        major, minor, micro = ctx.attr._interpreter_version_flag[BuildSettingInfo].value.split(".")
+        interpreter_version_info = struct(
+            major = major,
+            minor = minor,
+            micro = micro,
+        )
+    else:
+        fail(_MUST_SET_INTERPRETER_VERSION_FLAG)
+
     return struct(
         toolchain = py3_toolchain,
         files = files,
         python = interpreter,
+        interpreter_version_info = interpreter_version_info,
         uses_interpreter_path = uses_interpreter_path,
         flags = _INTERPRETER_FLAGS,
     )

diff --git a/py/private/py_unpacked_wheel.bzl b/py/private/py_unpacked_wheel.bzl
@@ -21,9 +21,9 @@ def _py_unpacked_wheel_impl(ctx):
         py_toolchain.python,
         "--python-version",
         "{}.{}.{}".format(
-            py_toolchain.toolchain.interpreter_version_info.major,
-            py_toolchain.toolchain.interpreter_version_info.minor,
-            py_toolchain.toolchain.interpreter_version_info.micro,
+            py_toolchain.interpreter_version_info.major,
+            py_toolchain.interpreter_version_info.minor,
+            py_toolchain.interpreter_version_info.micro,
         ),
         "--package-name",
         ctx.attr.py_package_name,
@@ -44,8 +44,8 @@ def _py_unpacked_wheel_impl(ctx):
         unpack_directory.basename,
         "lib",
         "python{}.{}".format(
-            py_toolchain.toolchain.interpreter_version_info.major,
-            py_toolchain.toolchain.interpreter_version_info.minor,
+            py_toolchain.interpreter_version_info.major,
+            py_toolchain.interpreter_version_info.minor,
         ),
         "site-packages",
     )
@@ -74,6 +74,10 @@ _attrs = {
     "py_package_name": attr.string(
         mandatory = True,
     ),
+    # NB: this is read by _resolve_toolchain in py_semantics.
+    "_interpreter_version_flag": attr.label(
+        default = "//py:interpreter_version",
+    ),
 }
 
 py_unpacked_wheel = rule(

diff --git a/py/private/py_venv.bzl b/py/private/py_venv.bzl
@@ -48,13 +48,13 @@ def _py_venv_rule_imp(ctx):
             "{{ARG_PYTHON}}": to_rlocation_path(ctx, py_toolchain.python),
             "{{ARG_VENV_LOCATION}}": paths.join(ctx.attr.location, ctx.attr.venv_name),
             "{{ARG_VENV_PYTHON_VERSION}}": "{}.{}.{}".format(
-                py_toolchain.toolchain.interpreter_version_info.major,
-                py_toolchain.toolchain.interpreter_version_info.minor,
-                py_toolchain.toolchain.interpreter_version_info.micro,
+                py_toolchain.interpreter_version_info.major,
+                py_toolchain.interpreter_version_info.minor,
+                py_toolchain.interpreter_version_info.micro,
             ),
             "{{ARG_PTH_FILE}}": to_rlocation_path(ctx, site_packages_pth_file),
             "{{EXEC_PYTHON_BIN}}": "python{}".format(
-                py_toolchain.toolchain.interpreter_version_info.major,
+                py_toolchain.interpreter_version_info.major,
             ),
         },
         is_executable = True,
@@ -115,6 +115,10 @@ _py_venv = rule(
         "_runfiles_lib": attr.label(
             default = "@bazel_tools//tools/bash/runfiles",
         ),
+        # NB: this is read by _resolve_toolchain in py_semantics.
+        "_interpreter_version_flag": attr.label(
+            default = "//py:interpreter_version",
+        ),
     },
     toolchains = [
         SH_TOOLCHAIN,

diff --git a/py/private/toolchain/autodetecting.bzl b/py/private/toolchain/autodetecting.bzl
@@ -1,5 +1,4 @@
 # buildifier: disable=module-docstring
-load("//py/private:py_semantics.bzl", _py_semantics = "semantics")
 
 def _autodetecting_py_wrapper_impl(rctx):
     which_python = rctx.which("python3")
@@ -8,7 +7,7 @@ def _autodetecting_py_wrapper_impl(rctx):
 
     # Check if `which_python` ends up being the final binary, or it's actually a wrapper itself.
     exec_result = rctx.execute(
-        [which_python] + _py_semantics.interpreter_flags + ["-c", "import sys; import os; print(os.path.realpath(sys.executable))"],
+        [which_python] + ["-B", "-I", "-c", "import sys; import os; print(os.path.realpath(sys.executable))"],
     )
 
     if exec_result.return_code == 0: