如何用Bazel为C++项目添加wxWidgets依赖及编译错误排查

问题背景 #

我正在开发一个依赖wxWidgets的C++项目，原本通过wxWidgets文档中的Makefile可以正常编译。改用Bazel作为构建系统后，运行bazel build //src:app --verbose_failures出现编译错误：找不到wx/setup.h头文件。

错误信息 #

In file included from external/wx/wx/defs.h:45,
                 from external/wx/wx/memory.h:14,
                 from external/wx/wx/object.h:19,
                 from external/wx/wx/utils.h:18,
                 from external/wx/wx/thrimpl.cpp:344:
external/wx/wx/platform.h:159:10: fatal error: wx/setup.h: No such file or directory
  159 | #include "wx/setup.h"
      |          ^~~~~~~~~~~~

当前配置文件 #

WORKSPACE文件 #

new_local_repository(
  name="wx",
  path="/usr/include/wx-3.2",

  build_file_content = """
package(default_visibility = ["//visibility:public"])
cc_library(
    name = "headers",
    hdrs = glob(["**/*.h"]),
    srcs = glob(["**/*.cpp"]),
    includes = ["/usr/include/wx-3.2"],
)
"""
)

new_local_repository(
  name="gtk-unicode",
  path="/usr/lib/wx/include/gtk3-unicode-3.2",

  build_file_content = """
package(default_visibility = ["//visibility:public"])
cc_library(
    name = "headers",
    hdrs = glob(["**/*.h"])
)
"""
)

src/BUILD文件 #

cc_library(
  name="agent",
  srcs=["Agent.cpp"],
  hdrs=["Agent.h"],
  deps=[":game"]
)

cc_library(
  name="game",
  srcs=["Game.cpp"],
  hdrs=["Game.h"],
)

cc_binary(
  name="app",
  srcs=["App.cpp"],
  deps=[":agent", ":game", "@wx//:headers", "@gtk-unicode//:headers"],
  copts=[
    "-Iexternal/wx",
    "-Iexternal/gtk-unicode",
    "-DWXUSINGDLL",
    "-D__WXGTK3__",
    "-D__WXGTK__",
    "-pthread",
    "-lwx_gtk3u_xrc-3.2",
    "-lwx_gtk3u_html-3.2",
    "-lwx_gtk3u_qa-3.2",
    "-lwx_gtk3u_core-3.2",
    "-lwx_baseu_xml-3.2",
    "-lwx_baseu_net-3.2",
    "-lwx_baseu-3.2"
  ]
)

解决方案 #

1. 修正WORKSPACE的include路径配置 #

wx/setup.h实际位于/usr/lib/wx/include/gtk3-unicode-3.2/wx/路径下，原配置未让Bazel正确识别该路径。修改两个仓库的includes为相对路径：

new_local_repository(
  name="wx",
  path="/usr/include/wx-3.2",
  build_file_content = """
package(default_visibility = ["//visibility:public"])
cc_library(
    name = "headers",
    hdrs = glob(["**/*.h"]),
    srcs = glob(["**/*.cpp"]),
    includes = ["."],
)
"""
)

new_local_repository(
  name="gtk-unicode",
  path="/usr/lib/wx/include/gtk3-unicode-3.2",
  build_file_content = """
package(default_visibility = ["//visibility:public"])
cc_library(
    name = "headers",
    hdrs = glob(["**/*.h"]),
    includes = ["."],
)
"""
)

2. 优化BUILD文件的编译与链接选项 #

• 移除冗余的-Iexternal/wx和-Iexternal/gtk-unicode，依赖库已通过includes提供头文件路径
• 将链接库参数从copts移至linkopts（copts用于编译选项，linkopts用于链接选项）

修改后的src/BUILD：

cc_library(
  name="agent",
  srcs=["Agent.cpp"],
  hdrs=["Agent.h"],
  deps=[":game"]
)

cc_library(
  name="game",
  srcs=["Game.cpp"],
  hdrs=["Game.h"],
)

cc_binary(
  name="app",
  srcs=["App.cpp"],
  deps=[":agent", ":game", "@wx//:headers", "@gtk-unicode//:headers"],
  copts=[
    "-DWXUSINGDLL",
    "-D__WXGTK3__",
    "-D__WXGTK__",
    "-pthread"
  ],
  linkopts=[
    "-lwx_gtk3u_xrc-3.2",
    "-lwx_gtk3u_html-3.2",
    "-lwx_gtk3u_qa-3.2",
    "-lwx_gtk3u_core-3.2",
    "-lwx_baseu_xml-3.2",
    "-lwx_baseu_net-3.2",
    "-lwx_baseu-3.2"
  ]
)

3. 原理说明 #

• 给gtk-unicode仓库添加includes = ["."]后，Bazel会将该仓库根目录加入头文件搜索路径，#include "wx/setup.h"就能被正确定位
• wx仓库改用相对路径includes = ["."]，避免绝对路径导致的依赖定位问题
• 分离编译与链接选项，符合Bazel的构建规则，减少配置混淆

内容的提问来源于stack exchange，提问作者ToMmyDong Chen