不是很明白，为什么内置的on_build还会再跑一遍

[PumpkinXD]

是这样的，我在rules/cosmocc.lua下仿照yacc的内置rule写了个 on_buildcmd_file
但是不知为何，内置流程的on_build仍然会再跑一遍(如下图)

清除了build以及删除了.xmake文件夹后的使用 ` xmake -vD ` 产生的输出

checking for platform ... linux
checking for architecture ... x86_64
checking for gcc ... /usr/bin/gcc
checkinfo: cannot runv(zig version), No such file or directory
checking for zig ... no
checkinfo: cannot runv(zig version), No such file or directory
checking for zig ... no
checking for cosmocc ... cosmocc/bin/cosmocc
rule:on_buildcmd_file
src/main.c
rule:on_buildcmd_file
src/another.c
checking for cosmocc ... cosmocc/bin/cosmocc
checking for the c compiler (cc) ... cosmocc
checking for the c compiler (cc) ... cosmocc
checking for cosmocc/bin/cosmocc ... ok
checking for flags (-fPIC) ... no
> cosmocc "-fPIC"
checkinfo: @programdir/core/sandbox/modules/os.lua:273: cosmocc: fatal error: -S flag not supported
compilation terminated.

stack traceback:
    [C]: in function 'error'
    [@programdir/core/base/os.lua:923]:
    [@programdir/core/sandbox/modules/os.lua:273]: in function 'runv'
    [@programdir/modules/detect/tools/gcc/has_flags.lua:42]:
[ 42%]: cache compiling.release src/main.c
cosmocc/bin/cosmocc -c -std=c11 -Iinclude -o build/.objs/main.com/unknown/unknown/release/src/main.c.o src/main.c
[ 42%]: cache compiling.release src/another.c
cosmocc/bin/cosmocc -c -std=c11 -Iinclude -o build/.objs/main.com/unknown/unknown/release/src/another.c.o src/another.c
checking for flags (-MMD -MF) ... no
> cosmocc "-MMD" "-MF" "/dev/null"
checkinfo: @programdir/core/sandbox/modules/os.lua:273: cosmocc: fatal error: -S flag not supported
compilation terminated.

stack traceback:
    [C]: in function 'error'
    [@programdir/core/base/os.lua:923]:
    [@programdir/core/sandbox/modules/os.lua:273]: in function 'runv'
    [@programdir/modules/detect/tools/gcc/has_flags.lua:42]:
checking for flags (-fdiagnostics-color=always) ... no
> cosmocc "-fdiagnostics-color=always"
checkinfo: @programdir/core/sandbox/modules/os.lua:273: cosmocc: fatal error: -S flag not supported
compilation terminated.

stack traceback:
    [C]: in function 'error'
    [@programdir/core/base/os.lua:923]:
    [@programdir/core/sandbox/modules/os.lua:273]: in function 'runv'
    [@programdir/modules/detect/tools/gcc/has_flags.lua:42]:
checking for flags (-fcolor-diagnostics) ... no
> cosmocc "-fcolor-diagnostics"
checkinfo: @programdir/core/sandbox/modules/os.lua:273: cosmocc: fatal error: -S flag not supported
compilation terminated.

stack traceback:
    [C]: in function 'error'
    [@programdir/core/base/os.lua:923]:
    [@programdir/core/sandbox/modules/os.lua:273]: in function 'runv'
    [@programdir/modules/detect/tools/gcc/has_flags.lua:42]:
checking for cosmocc ... cosmocc/bin/cosmocc
checking for the linker (ld) ... cosmocc
checking for flags (-fPIC) ... ok
> cosmocc "-fPIC"
[ 71%]: linking.release main.com
cosmocc/bin/cosmocc -o build/unknown/unknown/release/main.com build/.objs/main.com/unknown/unknown/release/src/main.c.o build/.objs/main.com/unknown/unknown/release/src/another.c.o

build cache stats:
cache directory: build/.build_cache
cache hit rate: 0%
cache hit: 0
cache miss: 2
new cached files: 2
remote cache hit: 0
remote new cached files: 0
preprocess failed: 0
compile fallback count: 2

[100%]: build ok, spent 0.881s

相关的文件:

rules/cosmocc.lua

-- rules/cosmocc.lua
rule("cosmolibc.c.binary")
    set_extensions(".c")
    -- set_sourcekinds("cosmocc")

    on_load(function (target)

        -- set default output binary
        target:set("kind", "binary") 
        
    end)




    on_buildcmd_file(function (target, batchcmds, sourcefile, opt)--?
        --print(target)
        cprint('${blue}rule:on_buildcmd_file')
        cprint('${yellow}'..sourcefile)
--         print(sourcefile)
--         local cosmocc="cosmocc/bin/cosmocc"
--         local objectfile = target:objectfile(sourcefile)
--         table.insert(target:objectfiles(), objectfile)
--         batchcmds:show_progress(opt.progress, "${color.build.object}compiling.cosmolibc.c %s", sourcefile)
--         -- local include=target.includes
--         -- print(include)
-- --         batchcmds:vrunv(cosmocc, {"-c","-std=c11","-o", objectfile,"-Iinclude", sourcefile},{shell=true})
-- --         batchcmds:compile(cosmocc, {"-c","-std=c11","-o", objectfile,"-Iinclude", sourcefile},{shell=true})
--         batchcmds:add_depfiles(sourcefile)
--         batchcmds:set_depmtime(os.mtime(objectfile))
--         batchcmds:set_depcache(target:dependfile(objectfile))
    end)

--     on_build_file(function (target, sourcefile, opt)
--             cprint('${blue}rule:on_build_file')
--             print(sourcefile)
--         end)

--
--     on_build(function (target)
--     cprint('${blue}rule:on_build')
--     end)



--     on_link(function (target)
--
--         cprint('${blue}rule:on_link')
--         import("core.base.option")
--         import("core.theme.theme")
--         import("core.project.config")
--         import("core.project.depend")
--         import("core.tool.compiler")
--         import("private.utils.progress")
--
--
--         -- print(target)
--         local cosmocc="cosmocc/bin/cosmocc"
--         print(target:objectfiles())
--
--         -- os.vrunv(cosmocc,{},{shell=true})
--         os.exit()
--     end)

rule_end()

toolchains/cosmocc.lua

--toolchains/cosmocc.lua
toolchain("cosmocc")
    set_homepage("https://justine.lol/cosmopolitan/index.html")
    set_description("Cosmopolitan Toolchain" )

    set_kind("standalone")

    set_toolset("cc", "gcc@cosmocc")
    set_toolset("cxx", "gcc@cosmocc", "gcc@cosmoc++" )
    set_toolset("ld", "gcc@cosmocc", "gcc@cosmoc++")
    set_toolset("sh", "gcc@cosmocc", "gcc@cosmoc++")
    set_toolset("ar", "gcc@cosmoarar")
    -- set_toolset("strip", "strip") -- aarch64-unknown-cosmo-strip or x86_64-unknown-cosmo-strip ?
    set_toolset("mm", "gcc@cosmocc")
    set_toolset("mxx", "gcc@cosmocc", "gcc@cosmoc++")
    set_toolset("as", "gcc@cosmocc")

    on_check(function (toolchain)
        import("lib.detect.find_tool")
        local cosmocc=find_tool("cosmocc", {paths={"cosmocc/bin"},check = function (tool) os.runv(tool,{"--version"},{shell= true }) end})
--         print(cosmocc)
        return cosmocc
    end)


    on_load(function (toolchain)
        local cc
        local ar

--      @see https://github.com/jart/cosmopolitan/tree/master/tool/cosmocc#gotchas
        if((is_host("windows"))and(is_subhost("windows")))then
            cprint('${bright red}I guess you should run it with WSL/MSYS/cygwin/mingw')
            os.exit()
        end

        toolchain:set("bindir","cosmocc/bin")

--         import("lib.detect.find_tool")
--         local toolchain_exist = find_tool("cosmocc", {paths={"cosmocc/bin"},check = function (tool) os.runv(tool,{"--version"},{shell=true}) end})
--         if(not toolchain_exist)
--             import("net.http")
--             import("utils.progress")



--             print("cosmocc not found, now downloading...")
--             http.download("https://cosmo.zip/pub/cosmocc/cosmocc.zip","cosmocc.zip")
--             import("utils.archive")
--             archive.extract("cosmocc.zip","cosmocc")
--             print("cosmocc downloaded.")
--         end



        if (os.arch()=="x86_64")then
            toolchain:set("strip","gcc@x86_64-unknown-cosmo-strip")
        elseif (os.arch()=="aarch64")then
            toolchain:set("strip","gcc@aarch64-unknown-cosmo-strip")
        end 

        -- copyed from gcc toolchain
        -- local march
        -- if march then
        --     toolchain:add("cxflags", march)
        --     toolchain:add("mxflags", march)
        --     toolchain:add("asflags", march)
        --     toolchain:add("ldflags", march)
        --     toolchain:add("shflags", march)
        --     end 
        

    end)

    -- on_build_file(function () 
        
    -- end)
    -- on_link(function (target) 
        
    -- end)

toolchain_end()

xmake.lua

-- xmake.lua
includes("toolchains/cosmocc.lua")
includes("rules/cosmocc.lua")

target("main.com")
    set_kind("binary")
    set_toolchains("cosmocc")
    set_plat("unknown")
    set_arch("unknown") -- for now(2023-12-26) APE supports amd64 and aarch64, remove this comment when riscv64 and loong64 are supported
--     set_extension("com") -- Causing "cosmocc: fatal error: build/.objs/main/unknown/unknown/release/src/main.c.o: linker input missing concomitant build/.objs/main/unknown/unknown/release/src/.aarch64/main.c.o file" Error
    set_languages("c11","cxx14") -- c11 and cpp14 https://xmake.io/#/manual/project_target?id=targetset_languages
    add_includedirs("include")
    add_files("src/*.c",{rule = "cosmolibc.c.binary"})
--     add_files("src/*.cpp") -- Causing "cannot match add_files("src/*.cpp") in target(main.com)" Warning if c++ source file(s) are not exist inside "src"

target_end()

[waruqi]

没有内置之分，多个 rule 存在 on_build 都会被执行，用户如果定义了多个 rule ，也是一样。。xmake内置的构建，也是 rule 。。等价的

[PumpkinXD]

那么 有办法可以阻止内置的构建跑起来么

[waruqi]

目前走 rule 没有，只有 target 的 on_build 可以完全重写内置的。