使用Bazel构建ncurses代码时出错：'unctrl'类型冲突

问题描述 #

基于Bazel构建的ncurses项目，迁移至Bazel 8.0.0 LTS的bzlmod后，使用Bazel中央仓库的ncurses模块构建时出现编译错误，提示conflicting types for 'unctrl'。具体错误如下：

$ bazel build //foo:color --verbose_failures
INFO: Analyzed target //foo:color (0 packages loaded, 0 targets configured).
ERROR: /Users/dzc/Projects/davidzchen/bazel-ncurses-example/foo/BUILD:3:11: Compiling foo/color.cc failed: (Exit 1): cc_wrapper.sh failed: error executing CppCompile command (from target //foo:color)
  (cd /private/var/tmp/_bazel_dzc/87450ce08cbc0c792b19d6253d30d152/sandbox/darwin-sandbox/143/execroot/_main && \
  exec env - \
    PATH='/Users/dzc/Library/Caches/bazelisk/downloads/sha256/ea529c3c03d6981e13e25af126b63b41435c9a42bf28435bbabbe3b11542ddcf/bin:/opt/homebrew/opt/ruby/bin:/opt/homebrew/opt/llvm/bin:/opt/local/bin:/opt/local/sbin:/Users/dzc/.bin:/Users/dzc/.local/bin:/usr/local/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Library/Apple/usr/bin:/Library/TeX/texbin:/Applications/VMware Fusion.app/Contents/Public:~/.dotnet/tools:/Library/Frameworks/Mono.framework/Versions/Current/Commands:/opt/homebrew/opt/ruby/bin:/opt/homebrew/opt/llvm/bin:/Applications/iTerm.app/Contents/Resources/utilities:/Users/dzc/go/bin:/opt/homebrew/opt/go/libexec/bin:/Library/Frameworks/Mono.framework/Commands:/Users/dzc/.antigen/bundles/robbyrussell/oh-my-zsh/lib:/Users/dzc/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/history-substring-search:/Users/dzc/.antigen/bundles/zsh-users/zsh-syntax-highlighting:/Users/dzc/.antigen/bundles/zsh-users/zsh-completions:/Users/dzc/.antigen/bundles/zsh-users/zsh-autosuggestions' \
    PWD=/proc/self/cwd \
  external/rules_cc++cc_configure_extension+local_config_cc/cc_wrapper.sh -U_FORTIFY_SOURCE -fstack-protector -Wall -Wthread-safety -Wself-assign -Wunused-but-set-parameter -Wno-free-nonheap-object -fcolor-diagnostics -fno-omit-frame-pointer '-std=c++17' '-frandom-seed=bazel-out/darwin_arm64-fastbuild/bin/foo/_objs/color/color.o' -iquote . -iquote bazel-out/darwin_arm64-fastbuild/bin -iquote external/ncurses+ -iquote bazel-out/darwin_arm64-fastbuild/bin/external/ncurses+ -isystem external/ncurses+/include -isystem bazel-out/darwin_arm64-fastbuild/bin/external/ncurses+/include -isystem external/ncurses+/ncurses -isystem bazel-out/darwin_arm64-fastbuild/bin/external/ncurses+/ncurses '-mmacosx-version-min=15.2' -MD -MF bazel-out/darwin_arm64-fastbuild/bin/foo/_objs/color/color.d '-std=c++20' -c foo/color.cc -o bazel-out/darwin_arm64-fastbuild/bin/foo/_objs/color/color.o -no-canonical-prefixes -Wno-builtin-macro-redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"' '-D__TIME__="redacted"' -Xclang '-fmodule-name=//foo:color' -Xclang '-fmodule-map-file=bazel-out/darwin_arm64-fastbuild/bin/foo/color.cppmap' -Xclang -fno-cxx-modules -fmodules-strict-decluse -Wprivate-header -Xclang '-fmodule-map-file=external/rules_cc++cc_configure_extension+local_config_cc/module.modulemap' -Xclang '-fmodule-map-file=bazel-out/darwin_arm64-fastbuild/bin/external/ncurses+/ncurses.cppmap')
# Configuration: 9b382b18c38178c86436d40b630070f6a7b54b2d54b8541e3a8dda9e825538d4
# Execution platform: @@platforms//host:host

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
In file included from foo/color.cc:3:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ncurses.h:2918:
bazel-out/darwin_arm64-fastbuild/bin/external/ncurses+/include/unctrl.h:61:54: error: conflicting types for 'unctrl'
   61 | NCURSES_EXPORT(NCURSES_CONST char *) NCURSES_SP_NAME(unctrl) (SCREEN*, chtype);
      |                                                      ^
bazel-out/darwin_arm64-fastbuild/bin/external/ncurses+/include/unctrl.h:58:38: note: previous declaration is here
   58 | NCURSES_EXPORT(NCURSES_CONST char *) unctrl (chtype);
      |                                      ^
1 error generated.
Target //foo:color failed to build
INFO: Elapsed time: 2.201s, Critical Path: 0.91s
INFO: 97 processes: 11 internal, 86 darwin-sandbox.
ERROR: Build did NOT complete successfully

已知bazel build @ncurses可成功执行，但构建项目目标时Bazel加载系统ncurses.h而非远程归档文件，添加common --incompatible_strict_action_env至.bazelrc后问题未解决。环境为Bazel 8.0.0、macOS Sequoia 15.2。

原因分析 #

1. 头文件冲突：macOS SDK自带的ncurses.h会包含系统版本的unctrl.h，而Bazel中央仓库的ncurses模块也提供了自己的unctrl.h，两者对unctrl函数的声明不一致（系统版本无SCREEN*参数，远程版本有该参数），导致类型冲突。
2. include路径优先级：Bazel默认编译配置中，系统SDK的头文件路径优先级高于远程ncurses模块的include路径，使得编译器优先找到系统的ncurses.h，进而引入冲突的头文件。

解决方法 #

方法1：调整头文件包含顺序，优先使用远程ncurses头文件 #

修改项目中目标的BUILD配置，强制编译器先查找远程ncurses的include目录，覆盖系统头文件：

cc_binary(
    name = "color",
    srcs = ["color.cc"],
    deps = ["@ncurses//:ncurses"],
    # 确保远程ncurses的头文件路径优先级最高
    copts = ["-isystem $(execpath @ncurses//:include)"],
    includes = ["external/ncurses/include"],
)

方法2：通过bzlmod配置增强依赖隔离 #

在MODULE.bazel中确保ncurses模块正确引入，并添加额外配置强化隔离：

bazel_dep(name = "ncurses", version = "6.4.20240210")

# 禁用系统ncurses的自动检测
build_setting(
    name = "ncurses_disable_system",
    build_setting_default = "true",
    visibility = ["//visibility:public"],
)

方法3：定义宏避免头文件重复包含 #

在编译选项中添加宏定义，阻止系统ncurses头文件的部分内容加载：

cc_binary(
    name = "color",
    srcs = ["color.cc"],
    deps = ["@ncurses//:ncurses"],
    copts = [
        "-D NCURSES_NOMACROS",
        "-D NCURSES_INCLUDED",
    ],
)

验证 #

修改配置后重新执行构建命令：

bazel build //foo:color --verbose_failures

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