blob: dfecf2c27eec5b8613285aae109725e8b3feb6d8 [file] [log] [blame]
This file contains a way to set flags from BUILD.bazel instead of requiring users to set them from
the CLI. This allows us to have tests that build with a specific set of features (e.g. the pdf
backend or the codecs) without having a large number of flags to set (easier to forget).
It uses the same core implementation as cc_binary_with_flags.
It is based off of:
load("@skia_user_config//:copts.bzl", "DEFAULT_COPTS")
load("@skia_user_config//:linkopts.bzl", "DEFAULT_LINKOPTS")
load("//bazel:cc_binary_with_flags.bzl", "with_flags_transition")
def _transition_rule_impl(ctx):
executable_src = ctx.executable.actual_test
executable_dst = ctx.actions.declare_file(
tools = [executable_src],
outputs = [executable_dst],
command = "cp %s %s" % (executable_src.path, executable_dst.path),
runfiles = ctx.attr.actual_test[0][DefaultInfo].default_runfiles
return [DefaultInfo(runfiles = runfiles, executable = executable_dst)]
# This rule must end with a _test suffix or Bazel doesn't allow the test attribute to be true.
transition_test = rule(
implementation = _transition_rule_impl,
attrs = {
# set_flags is a dictionary with the keys being the short-form of a flag name
# (e.g. the part that comes after the colon) and the value being a list of values
# that the flag should be set to, regardless of the relevant CLI flags.
"set_flags": attr.string_list_dict(),
# This is the cc_test that should be made with the flags being set.
# Note specifically how it is modified using with_flags_transition, which
# ensures that the flags propagates down the graph. Must be executable
# so the _transition_rule_impl can use it as an executable.
"actual_test": attr.label(cfg = with_flags_transition, executable = True),
# This is a stock Bazel requirement for any rule that uses Starlark
# transitions. It's okay to copy the below verbatim for all such rules.
# The purpose of this requirement is to give the ability to restrict
# which packages can invoke these rules, since Starlark transitions
# make much larger graphs possible that can have memory and performance
# consequences for your build. The allowlist defaults to "everything".
# But you can redefine it more strictly if you feel that's prudent.
"_allowlist_function_transition": attr.label(
default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
# Means it works with "$ bazel test".
test = True,
def cc_test_with_flags(name, set_flags = {}, copts = DEFAULT_COPTS, linkopts = DEFAULT_LINKOPTS, args = [], **kwargs):
"""Builds a cc_test as if set_flags were set on the CLI.
name: string, the name for the rule that is the binary, but with the flags changed via
a transition. Any dependents should use this name.
set_flags: dictionary of string to list of strings. The keys should be the name of the
flag, and the values should be the desired valid settings for that flag.
copts: a list of strings or select statements that control the compiler flags.
It has a sensible list of defaults.
linkopts: a list of strings or select statements that control the linker flags.
It has a sensible list of defaults.
args: A list of strings with any command-line arguments to pass to the binary.
**kwargs: Any flags that a cc_binary normally takes.
cc_test_name = name + "_native_test"
name = name,
actual_test = ":%s" % cc_test_name,
set_flags = set_flags,
args = args,
testonly = True,
tags = kwargs.get("tags", [])
tags.append("manual") # We want to exclude this helper test from bazel test foo/...
kwargs["tags"] = tags
name = cc_test_name,
copts = copts,
linkopts = linkopts,