cmd/go: link error when building net/http on macOS

[nicolas42]

What version of Go are you using (go version)?

$ go version

go version go1.14.2 darwin/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

macos 10.13.6

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/nick2/Library/Caches/go-build"
GOENV="/Users/nick2/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/nick2/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="/Users/nick2/opt/miniconda3/bin/x86_64-apple-darwin13.4.0-ar"
CC="x86_64-apple-darwin13.4.0-clang"
CXX="x86_64-apple-darwin13.4.0-clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/dm/2w2btgwj4f38934mhkm7w4700000gp/T/go-build530020094=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Ran this very simple script which uses the net/http package

package main

import (
"flag"
"log"
"net/http"
)

func main() {
port := flag.String("p", "8080", "port to serve on")
directory := flag.String("d", ".", "the directory of static file to host")
flag.Parse()

http.Handle("/", http.FileServer(http.Dir(*directory)))

log.Printf("Serving %s on HTTP port: %s\n", *directory, *port)
log.Fatal(http.ListenAndServe(":"+*port, nil))

}

What did you expect to see?

Serving on HTTP port 8080

What did you see instead?

runtime/cgo

ld: warning: ld: warning: ignoring file /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/lib/libpthread.tbd, file was built for unsupported file format ( 0x2D 0x2D 0x2D 0x20 0x21 0x74 0x61 0x70 0x69 0x2D 0x74 0x62 0x64 0x2D 0x76 0x33 ) which is not the architecture being linked (x86_64): /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/lib/libpthread.tbdignoring file /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/lib/libSystem.tbd, file was built for unsupported file format ( 0x2D 0x2D 0x2D 0x20 0x21 0x74 0x61 0x70 0x69 0x2D 0x74 0x62 0x64 0x2D 0x76 0x33 ) which is not the architecture being linked (x86_64): /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/lib/libSystem.tbd

Undefined symbols for architecture x86_64:
"___stack_chk_fail", referenced from:
_x_cgo_init in _x004.o
__cgo_sys_thread_start in _x004.o
"___stack_chk_guard", referenced from:
_x_cgo_init in _x004.o
__cgo_sys_thread_start in _x004.o
"___stderrp", referenced from:
__cgo_sys_thread_start in _x004.o
_x_cgo_sys_thread_create in _x005.o
_x_cgo_thread_start in _x008.o
"_abort", referenced from:
__cgo_sys_thread_start in _x004.o
_x_cgo_sys_thread_create in _x005.o
_x_cgo_thread_start in _x008.o
"_fprintf", referenced from:
__cgo_sys_thread_start in _x004.o
_x_cgo_sys_thread_create in _x005.o
"_free", referenced from:
_threadentry in _x004.o
"_fwrite", referenced from:
_x_cgo_thread_start in _x008.o
"_malloc", referenced from:
_x_cgo_thread_start in _x008.o
"_nanosleep", referenced from:
_x_cgo_sys_thread_create in _x005.o
__cgo_try_pthread_create in _x005.o
"_pthread_attr_destroy", referenced from:
_x_cgo_init in _x004.o
"_pthread_attr_getstacksize", referenced from:
_x_cgo_init in _x004.o
__cgo_sys_thread_start in _x004.o
"_pthread_attr_init", referenced from:
_x_cgo_init in _x004.o
__cgo_sys_thread_start in _x004.o
"_pthread_cond_broadcast", referenced from:
_x_cgo_notify_runtime_init_done in _x005.o
"_pthread_cond_wait", referenced from:
__cgo_wait_runtime_init_done in _x005.o
"_pthread_create", referenced from:
_x_cgo_sys_thread_create in _x005.o
__cgo_try_pthread_create in _x005.o
(maybe you meant: __cgo_try_pthread_create)
"_pthread_detach", referenced from:
_x_cgo_sys_thread_create in _x005.o
__cgo_try_pthread_create in _x005.o
"_pthread_mutex_lock", referenced from:
__cgo_wait_runtime_init_done in _x005.o
_x_cgo_notify_runtime_init_done in _x005.o
_x_cgo_set_context_function in _x005.o
__cgo_get_context_function in _x005.o
"_pthread_mutex_unlock", referenced from:
__cgo_wait_runtime_init_done in _x005.o
_x_cgo_notify_runtime_init_done in _x005.o
_x_cgo_set_context_function in _x005.o
__cgo_get_context_function in _x005.o
"_pthread_sigmask", referenced from:
__cgo_sys_thread_start in _x004.o
"_setenv", referenced from:
_x_cgo_setenv in _x006.o
(maybe you meant: _x_cgo_setenv)
"_strerror", referenced from:
__cgo_sys_thread_start in _x004.o
_x_cgo_sys_thread_create in _x005.o
"_unsetenv", referenced from:
_x_cgo_unsetenv in _x006.o
(maybe you meant: _x_cgo_unsetenv)
ld: symbol(s) not found for architecture x86_64
clang-4.0: error: linker command failed with exit code 1 (use -v to see invocation)

=============================

It works if I disable CGO in the terminal.

CGO_ENABLED=0 go run serve.go

I'm confused because I don't use cgo in any of the code as far as I can tell.

[bcmills]

These sorts of failures on macOS typically indicate a corrupted or otherwise-broken C toolchain, typically something involving Anaconda

I note the following in your go env output, which indeed suggests a broken Anaconda toolchain:

AR="/Users/nick2/opt/miniconda3/bin/x86_64-apple-darwin13.4.0-ar"
CC="x86_64-apple-darwin13.4.0-clang"
CXX="x86_64-apple-darwin13.4.0-clang++"

What happens if you uninstall miniconda3 and/or reinstall the default macOS clang toolchain?

What happens if you explicitly set CC=/usr/bin/clang (as described in #32559 (comment))?

[bcmills]

(This looks like a duplicate of #29597.)

[gopherbot]

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