feat: basic build data with stamping

CHANGELOG.md

@@ -59,6 +59,8 @@ END_UNRELEASED_TEMPLATE
 {#v0-0-0-changed}
 ### Changed
 * (binaries/tests) The `PYTHONBREAKPOINT` environment variable is automatically inherited
+* (binaries/tests) The {obj}`stamp` attribute now transitions the Bazel builtin
+  {obj}`--stamp` flag.
 
 {#v0-0-0-fixed}
 ### Fixed
@@ -69,6 +71,9 @@ END_UNRELEASED_TEMPLATE
 ### Added
 * (binaries/tests) {obj}`--debugger`: allows specifying an extra dependency
   to add to binaries/tests for custom debuggers.
+* (binaries/tests) Build information is now included in binaries and tests.
+  Use the `bazel_binary_info` module to access it. The {flag}`--stamp` flag will
+  add {flag}`--workspace_status` information.
 
 {#v1-8-0}
 ## [1.8.0] - 2025-12-19

python/private/BUILD.bazel

@@ -21,6 +21,7 @@ load(":print_toolchain_checksums.bzl", "print_toolchains_checksums")
 load(":py_exec_tools_toolchain.bzl", "current_interpreter_executable")
 load(":sentinel.bzl", "sentinel")
 load(":stamp.bzl", "stamp_build_setting")
+load(":uncachable_version_file.bzl", "define_uncachable_version_file")
 
 package(
     default_visibility = ["//:__subpackages__"],
@@ -99,6 +100,14 @@ bzl_library(
     ],
 )
 
+alias(
+    name = "build_data_writer",
+    actual = select({
+        "@platforms//os:windows": ":build_data_writer.ps1",
+        "//conditions:default": ":build_data_writer.sh",
+    }),
+)
+
 bzl_library(
     name = "builders_bzl",
     srcs = ["builders.bzl"],
@@ -683,6 +692,10 @@ bzl_library(
     ],
 )
 
+define_uncachable_version_file(
+    name = "uncachable_version_file",
+)
+
 bzl_library(
     name = "version_bzl",
     srcs = ["version.bzl"],

python/private/attributes.bzl

@@ -450,8 +450,20 @@ Whether to encode build information into the binary. Possible values:
 
 Stamped binaries are not rebuilt unless their dependencies change.
 
-WARNING: Stamping can harm build performance by reducing cache hits and should
+Stamped build information can accessed using the `bazel_binary_info` module.
+See the [Accessing build information docs] for more information.
+
+:::{warning}
+Stamping can harm build performance by reducing cache hits and should
 be avoided if possible.
+
+In addition, this transitions the {obj}`--stamp` flag, which can additional
+config state overhead.
+:::
+
+:::{note}
+Stamping of build data output is always disabled for the exec config.
+:::
 """,
             default = -1,
         ),

python/private/build_data_writer.ps1

@@ -0,0 +1,18 @@
+$OutputPath = $env:OUTPUT
+
+Add-Content -Path $OutputPath -Value "TARGET $env:TARGET"
+Add-Content -Path $OutputPath -Value "CONFIG_ID $env:CONFIG_ID"
+Add-Content -Path $OutputPath -Value "CONFIG_MODE $env:CONFIG_MODE"
+Add-Content -Path $OutputPath -Value "STAMPED $env:STAMPED"
+
+$VersionFilePath = $env:VERSION_FILE
+if (-not [string]::IsNullOrEmpty($VersionFilePath)) {
+    Get-Content -Path $VersionFilePath | Add-Content -Path $OutputPath
+}
+
+$InfoFilePath = $env:INFO_FILE
+if (-not [string]::IsNullOrEmpty($InfoFilePath)) {
+    Get-Content -Path $InfoFilePath | Add-Content -Path $OutputPath
+}
+
+exit 0

python/private/build_data_writer.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+echo "TARGET $TARGET" >> $OUTPUT
+echo "CONFIG_MODE $CONFIG_MODE" >> $OUTPUT
+echo "STAMPED $STAMPED" >> $OUTPUT
+if [ -n "$VERSION_FILE" ]; then
+  cat "$VERSION_FILE" >> "$OUTPUT"
+fi
+if [ -n "$INFO_FILE" ]; then
+  cat "$INFO_FILE" >> "$OUTPUT"
+fi
+exit 0

python/private/common.bzl

@@ -43,34 +43,25 @@ PYTHON_FILE_EXTENSIONS = [
 
 def create_binary_semantics_struct(
         *,
-        get_central_uncachable_version_file,
         get_native_deps_dso_name,
-        should_build_native_deps_dso,
-        should_include_build_data):
+        should_build_native_deps_dso):
     """Helper to ensure a semantics struct has all necessary fields.
 
     Call this instead of a raw call to `struct(...)`; it'll help ensure all
     the necessary functions are being correctly provided.
 
     Args:
-        get_central_uncachable_version_file: Callable that returns an optional
-            Artifact; this artifact is special: it is never cached and is a copy
-            of `ctx.version_file`; see py_builtins.copy_without_caching
         get_native_deps_dso_name: Callable that returns a string, which is the
             basename (with extension) of the native deps DSO library.
         should_build_native_deps_dso: Callable that returns bool; True if
             building a native deps DSO is supported, False if not.
-        should_include_build_data: Callable that returns bool; True if
-            build data should be generated, False if not.
     Returns:
         A "BinarySemantics" struct.
     """
     return struct(
         # keep-sorted
-        get_central_uncachable_version_file = get_central_uncachable_version_file,
         get_native_deps_dso_name = get_native_deps_dso_name,
         should_build_native_deps_dso = should_build_native_deps_dso,
-        should_include_build_data = should_include_build_data,
     )
 
 def create_cc_details_struct(