Bazel - “：target”没有强制提供者：“TemplateVariableInfo”

Question

我想在 bazel 中为我的 genrule 创建一个工具链。我创建了一个名为 toolchain.bzl 的文件，该文件中的源代码是这样的：

BarInfo = provider(
    fields = {
        "bar": "path to bar executable",
    },
    doc = "Defines a Bar toolchain based on an SDK",
)

def _bar_toolchain_impl(ctx):
    bar_info = ctx.attr.path
    platform_bar_info = platform_common.ToolchainInfo(
        bar_info = BarInfo(bar = bar_info),
    )
    return [platform_bar_info]

bar_toolchain = rule(
    implementation = _bar_toolchain_impl,
    attrs = {
        "path": attr.string(
            doc = "path to bar executable",
            mandatory = False,
        ),
    },
)

我把这个写在 BUILD 文件中。

load(":toolchain.bzl", "bar_toolchain")

toolchain_type(
    name = "toolchain_type",
    visibility = ["//visibility:public"],
)

bar_toolchain(
    name = "bar_toolchain",
    path = "/usr/local/bin/bar",
    visibility = ["//visibility:public"],
)

toolchain(
    name = "bar_linux",
    target_compatible_with = [
        "@platforms//os:linux",
        "@platforms//cpu:x86_64",
    ],
    toolchain = "//:bar_toolchain",
    toolchain_type = "//:toolchain_type",
    visibility = ["//visibility:public"],
)

genrule(
    name = "build_bar",
    srcs = glob(["**/*.bar"]),
    outs = ["a.sh"],
    cmd = """
        touch a.sh
    """,
    toolchains = ["//:toolchain_type"],
)

但当我跑步时

巴泽尔构建 //:build_bar

我收到这个错误

'//:toolchain_type' 没有强制提供程序：'TemplateVariableInfo'。

我可以做什么来解决这个问题？

Answer 1

genrule的toolchains属性只能用于访问特定于工具链的“make 变量”，这些变量被替换到 的genrule命令字符串中。由于您的工具链未声明任何 make 变量，因此 Bazel 会出错。make 变量文档中描述了定义工具链make 变量。