feat: add the zig_configure* rule family to support transitioning on the Zig build mode

.bazelrc

@@ -7,8 +7,8 @@ import %workspace%/.bazelrc.flags
 # Deleted packages for integration tests.
 # To update these lines, execute
 # `bazel run @contrib_rules_bazel_integration_test//tools:update_deleted_packages`
-build --deleted_packages=e2e/workspace,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace
-query --deleted_packages=e2e/workspace,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace
+build --deleted_packages=e2e/workspace,e2e/workspace/configure-mode,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace
+query --deleted_packages=e2e/workspace,e2e/workspace/configure-mode,e2e/workspace/multiple-sources-and-packages-test,e2e/workspace/multiple-sources-binary,e2e/workspace/simple-binary,e2e/workspace/simple-library,e2e/workspace/simple-test,e2e/workspace/transitive-zig-packages-binary,e2e/workspace/transitive-zig-packages-binary/hello-world,e2e/workspace/transitive-zig-packages-binary/hello-world/data,e2e/workspace/transitive-zig-packages-binary/hello-world/data/hello,e2e/workspace/transitive-zig-packages-binary/hello-world/data/world,e2e/workspace/transitive-zig-packages-binary/hello-world/io,e2e/workspace/zig-package-binary,e2e/workspace/zig-package-binary/data,e2e/workspace/zig-package-binary/io,zig/tests/integration_tests/workspace
 
 # Load any settings specific to the current user.
 # .bazelrc.user should appear in .gitignore so that settings are not shared with team members

e2e/workspace/configure-mode/BUILD.bazel

@@ -0,0 +1,124 @@
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
+load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
+load(
+    "@rules_zig//zig:defs.bzl",
+    "zig_binary",
+    "zig_configure",
+    "zig_configure_binary",
+    "zig_configure_test",
+    "zig_library",
+    "zig_test",
+)
+load(":defs.bzl", "run")
+
+zig_library(
+    name = "library",
+    main = "library.zig",
+    tags = ["manual"],
+)
+
+zig_configure(
+    name = "library_debug",
+    actual = ":library",
+    mode = "debug",
+)
+
+zig_configure(
+    name = "library_release_safe",
+    actual = ":library",
+    mode = "release_safe",
+)
+
+genrule(
+    name = "library_debug_symbol",
+    srcs = [":library_debug"],
+    outs = ["library_debug_symbol.txt"],
+    cmd = "$(NM) -j --defined-only $(SRCS) | grep Debug > $(OUTS)",
+    toolchains = ["@bazel_tools//tools/cpp:current_cc_toolchain"],
+)
+
+genrule(
+    name = "library_release_safe_symbol",
+    srcs = [":library_release_safe"],
+    outs = ["library_release_safe_symbol.txt"],
+    cmd = "$(NM) -j --defined-only $(SRCS) | grep ReleaseSafe > $(OUTS)",
+    toolchains = ["@bazel_tools//tools/cpp:current_cc_toolchain"],
+)
+
+build_test(
+    name = "library_test",
+    targets = [
+        ":library_debug_symbol",
+        ":library_release_safe_symbol",
+    ],
+)
+
+zig_binary(
+    name = "binary",
+    main = "binary.zig",
+    tags = ["manual"],
+)
+
+zig_configure_binary(
+    name = "binary_debug",
+    actual = ":binary",
+    mode = "debug",
+)
+
+zig_configure_binary(
+    name = "binary_release_safe",
+    actual = ":binary",
+    mode = "release_safe",
+)
+
+# NOTE using genrule instead of run fails with Bazel version 5.3.2.
+#   It seems that the configuration transition is not handled correctly by
+#   genrule in Bazel version 5.3.2.
+
+run(
+    name = "binary_debug_output",
+    out = "binary_debug_output.actual",
+    tool = ":binary_debug",
+)
+
+run(
+    name = "binary_release_safe_output",
+    out = "binary_release_safe_output.actual",
+    tool = ":binary_release_safe",
+)
+
+diff_test(
+    name = "binary_debug_output_test",
+    file1 = ":binary_debug_output.expected",
+    file2 = ":binary_debug_output.actual",
+)
+
+diff_test(
+    name = "binary_release_safe_output_test",
+    file1 = ":binary_release_safe_output.expected",
+    file2 = ":binary_release_safe_output.actual",
+)
+
+zig_test(
+    name = "_test_debug",
+    main = "test_debug.zig",
+    tags = ["manual"],
+)
+
+zig_configure_test(
+    name = "test_debug",
+    actual = "_test_debug",
+    mode = "debug",
+)
+
+zig_test(
+    name = "_test_release_safe",
+    main = "test_release_safe.zig",
+    tags = ["manual"],
+)
+
+zig_configure_test(
+    name = "test_release_safe",
+    actual = "_test_release_safe",
+    mode = "release_safe",
+)

e2e/workspace/configure-mode/binary.zig

@@ -0,0 +1,9 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+pub fn main() void {
+    std.io.getStdOut().writer().print(
+        "{s}\n",
+        .{std.meta.tagName(builtin.mode)},
+    ) catch unreachable;
+}

e2e/workspace/configure-mode/binary_debug_output.expected

@@ -0,0 +1 @@
+Debug

e2e/workspace/configure-mode/binary_release_safe_output.expected

@@ -0,0 +1 @@
+ReleaseSafe

e2e/workspace/configure-mode/defs.bzl

@@ -0,0 +1,19 @@
+"""Implements a rule to run a binary and write its output to a file."""
+
+def _run_impl(ctx):
+    ctx.actions.run_shell(
+        outputs = [ctx.outputs.out],
+        tools = [ctx.executable.tool],
+        mnemonic = "RunBinary",
+        command = "{} > {}".format(ctx.executable.tool.path, ctx.outputs.out.path),
+        progress_message = "Running binary to create %{output}",
+    )
+    return [DefaultInfo(files = depset([ctx.outputs.out]))]
+
+run = rule(
+    _run_impl,
+    attrs = {
+        "out": attr.output(),
+        "tool": attr.label(executable = True, cfg = "exec"),
+    },
+)

e2e/workspace/configure-mode/library.zig

@@ -0,0 +1,8 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+comptime {
+    @export(internalName, .{ .name = @tagName(builtin.mode), .linkage = .Strong });
+}
+
+fn internalName() callconv(.C) void {}

e2e/workspace/configure-mode/test_debug.zig

@@ -0,0 +1,6 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+test "mode is Debug" {
+    try std.testing.expectEqual(std.builtin.Mode.Debug, builtin.mode);
+}

e2e/workspace/configure-mode/test_release_safe.zig

@@ -0,0 +1,6 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+test "mode is ReleaseSafe" {
+    try std.testing.expectEqual(std.builtin.Mode.ReleaseSafe, builtin.mode);
+}

zig/BUILD.bazel

@@ -38,6 +38,7 @@ bzl_library(
     visibility = ["//visibility:public"],
     deps = [
         "//zig/private:zig_binary",
+        "//zig/private:zig_configure",
         "//zig/private:zig_library",
         "//zig/private:zig_package",
         "//zig/private:zig_test",

zig/defs.bzl

@@ -4,8 +4,17 @@ load("//zig/private:zig_binary.bzl", _zig_binary = "zig_binary")
 load("//zig/private:zig_library.bzl", _zig_library = "zig_library")
 load("//zig/private:zig_package.bzl", _zig_package = "zig_package")
 load("//zig/private:zig_test.bzl", _zig_test = "zig_test")
+load(
+    "//zig/private:zig_configure.bzl",
+    _zig_configure = "zig_configure",
+    _zig_configure_binary = "zig_configure_binary",
+    _zig_configure_test = "zig_configure_test",
+)
 
 zig_binary = _zig_binary
 zig_library = _zig_library
 zig_package = _zig_package
 zig_test = _zig_test
+zig_configure = _zig_configure
+zig_configure_binary = _zig_configure_binary
+zig_configure_test = _zig_configure_test

zig/private/BUILD.bazel

@@ -48,6 +48,16 @@ bzl_library(
     ],
 )
 
+bzl_library(
+    name = "zig_configure",
+    srcs = ["zig_configure.bzl"],
+    visibility = ["//zig:__subpackages__"],
+    deps = [
+        ":settings",
+        "@bazel_skylib//lib:paths",
+    ],
+)
+
 bzl_library(
     name = "resolved_toolchain",
     srcs = ["resolved_toolchain.bzl"],
@@ -76,6 +86,7 @@ filegroup(
         ":toolchains_repo.bzl",
         ":versions.bzl",
         ":zig_binary.bzl",
+        ":zig_configure.bzl",
         ":zig_library.bzl",
         ":zig_package.bzl",
         ":zig_test.bzl",

zig/private/settings.bzl

@@ -20,6 +20,8 @@ MODE_ARGS = {
     "release_fast": ["-O", "ReleaseFast"],
 }
 
+MODE_VALUES = ["debug", "release_safe", "release_small", "release_fast"]
+
 def _settings_impl(ctx):
     args = []