Add support for bzlmod (excluding Python bindings) (#1615)

* Migrate to bzlmod

* Update Python version to PY3, as indicated by the actual source file.

* Migrate more libraries & first draft of direct pywheel rule usage in Bazel

* Integrate with nanobind and libpfm

* Make Python toolchain a dev dependency

* Undo py_wheel usage until later

* Added support for bzlmod for C++ parts of google_benchmark.

* Make //tools:all buildable with --enable_bzlmod

---------

Co-authored-by: Andy Christiansen <achristiansen@google.com>

7 files changed, 51 insertions, 12 deletions

diff --git a/MODULE.bazel b/MODULE.bazel
new file mode 100644
index 0000000..0337ccc
--- /dev/null
+++ b/MODULE.bazel
@@ -0,0 +1,34 @@
+module(name = "com_github_google_benchmark", version="1.8.0")
+
+bazel_dep(name = "bazel_skylib", version = "1.4.1")
+bazel_dep(name = "platforms", version = "0.0.6")
+bazel_dep(name = "rules_foreign_cc", version = "0.9.0")
+bazel_dep(name = "rules_cc", version = "0.0.6")
+bazel_dep(name = "rules_python", version = "0.23.1")
+bazel_dep(name = "googletest", version = "1.12.1", repo_name = "com_google_googletest")
+bazel_dep(name = "libpfm", version = "4.11.0")
+
+# Register a toolchain for Python 3.9 to be able to build numpy. Python
+# versions >=3.10 are problematic.
+# A second reason for this is to be able to build Python hermetically instead
+# of relying on the changing default version from rules_python.
+
+python = use_extension("@rules_python//python/extensions:python.bzl", "python")
+python.toolchain(python_version = "3.9")
+
+# Extract the interpreter from the hermetic toolchain above, so we can use that
+# instead of the system interpreter for the pip compiplation step below.
+interpreter = use_extension("@rules_python//python/extensions:interpreter.bzl", "interpreter")
+interpreter.install(
+    name = "interpreter",
+    python_name = "python_3_9",
+)
+use_repo(interpreter, "interpreter")
+
+pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
+pip.parse(
+    name="tools_pip_deps",
+    incompatible_generate_aliases = True,
+    python_interpreter_target="@interpreter//:python",
+    requirements_lock="//tools:requirements.txt")
+use_repo(pip, "tools_pip_deps")
diff --git a/WORKSPACE b/WORKSPACE
index 74e7ebc..833590f 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -11,8 +11,8 @@ rules_foreign_cc_dependencies()
 load("@rules_python//python:pip.bzl", pip3_install="pip_install")
 
 pip3_install(
-   name = "py_deps",
-   requirements = "//:requirements.txt",
+   name = "tools_pip_deps",
+   requirements = "//tools:requirements.txt",
 )
 
 new_local_repository(
diff --git a/WORKSPACE.bzlmod b/WORKSPACE.bzlmod
new file mode 100644
index 0000000..9526376
--- /dev/null
+++ b/WORKSPACE.bzlmod
@@ -0,0 +1,2 @@
+# This file marks the root of the Bazel workspace.
+# See MODULE.bazel for dependencies and setup.
diff --git a/docs/releasing.md b/docs/releasing.md
index 6d3b613..cdf4159 100644
--- a/docs/releasing.md
+++ b/docs/releasing.md
@@ -8,13 +8,17 @@
     * `git log $(git describe --abbrev=0 --tags)..HEAD` gives you the list of
       commits between the last annotated tag and HEAD
     * Pick the most interesting.
-* Create one last commit that updates the version saved in `CMakeLists.txt` and the
-  `__version__` variable in `bindings/python/google_benchmark/__init__.py`to the release
-  version you're creating. (This version will be used if benchmark is installed from the
-  archive you'll be creating in the next step.)
+* Create one last commit that updates the version saved in `CMakeLists.txt`, `MODULE.bazel`
+  and the `__version__` variable in `bindings/python/google_benchmark/__init__.py`to the
+  release version you're creating. (This version will be used if benchmark is installed
+  from the archive you'll be creating in the next step.)
 
 ```
-project (benchmark VERSION 1.6.0 LANGUAGES CXX)
+project (benchmark VERSION 1.8.0 LANGUAGES CXX)
+```
+
+```
+module(name = "com_github_google_benchmark", version="1.8.0")
 ```
 
 ```python
@@ -22,7 +26,7 @@ project (benchmark VERSION 1.6.0 LANGUAGES CXX)
 
 # ...
 
-__version__ = "1.6.0"  # <-- change this to the release version you are creating
+__version__ = "1.8.0"  # <-- change this to the release version you are creating
 
 # ...
 ```
diff --git a/requirements.txt b/requirements.txt
deleted file mode 100644
index 1c8a4bd..0000000
--- a/requirements.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-numpy == 1.22
-scipy == 1.5.4
diff --git a/tools/BUILD.bazel b/tools/BUILD.bazel
index c0cbc64..d25caa7 100644
--- a/tools/BUILD.bazel
+++ b/tools/BUILD.bazel
@@ -1,4 +1,4 @@
-load("@py_deps//:requirements.bzl", "requirement")
+load("@tools_pip_deps//:requirements.bzl", "requirement")
 
 py_library(
     name = "gbench",
diff --git a/tools/requirements.txt b/tools/requirements.txt
index 3b3331b..afbc596 100644
--- a/tools/requirements.txt
+++ b/tools/requirements.txt
@@ -1 +1,2 @@
-scipy>=1.5.0
\ No newline at end of file
+numpy == 1.25
+scipy == 1.5.4