cmd/go: error: pointer is missing a nullability type specifier when building on catalina

[Tochemey]

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

$ go version
go version go1.13.3 darwin/amd64

Does this issue reproduce with the latest release?

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/arsenegandote/Library/Caches/go-build"
GOENV="/Users/arsenegandote/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/arsenegandote/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/Cellar/go/1.13.3/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.13.3/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="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/_9/v2g8jyjj051bj38hln17lchw0000gn/T/go-build584306134=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

go test -mod=vendor

What did you expect to see?

At least the test should run

What did you see instead?

runtime/cgo

In file included from _cgo_export.c:3:
/usr/local/include/stdlib.h:134:25: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:134:25: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:134:25: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:135:22: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:135:22: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:135:22: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:136:23: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:136:23: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:136:23: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:139:20: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:139:20: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:139:20: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:141:26: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:141:26: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:141:26: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:141:45: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:141:45: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:141:45: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:142:59: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:142:59: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:142:59: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:142:73: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:142:73: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:142:73: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:141:6: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:141:6: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:141:6: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:147:25: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:147:25: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:147:25: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:147:6: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:147:6: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:147:6: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:156:23: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:156:23: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:156:23: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:157:26: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:157:26: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:157:26: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:157:52: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:157:52: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:157:52: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:158:21: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:158:21: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:158:21: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:158:46: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:158:46: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:158:46: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:160:18: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:160:18: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:160:18: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:161:43: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:161:43: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:161:43: note: insert '_Nonnull' if the pointer should never be null
/usr/local/include/stdlib.h:161:57: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
/usr/local/include/stdlib.h:161:57: note: insert '_Nullable' if the pointer may be null
/usr/local/include/stdlib.h:161:57: note: insert '_Nonnull' if the pointer should never be null
fatal error: too many errors emitted, stopping now [-ferror-limit=]

Compilation finished with exit code 2

[ianlancetaylor]

Has clang really decided to enable the -Wnullability-completeness warning by default, as suggested by https://bcain-llvm.readthedocs.io/projects/clang/en/latest/DiagnosticsReference/#wnullability-completeness ? That seems designed to break all existing code. I must be missing something.

[ianlancetaylor]

Note that these warnings are for /usr/local/include/stdlib.h, which does not come from Go. Is that the version of stdlib.h that corresponds to the C compiler that you are using?

[Tochemey]

@ianlancetaylor I cannot really tell. I just did an upgrade to catalina and installed golang. So when I try to build I got the error. During the installation I did not get any errors that could have given a hint.

[ianlancetaylor]

Unless someone else is seeing this problem on catalina, I suspect this is a problem with the installation on your system.

[ianlancetaylor]

Sorry, I mean a problem with the XCode installation. I don't see a reason to think that there is anything wrong with the Go installation.

[42yeah]

Had the same problem. Upgraded to catalina and this appears:

# runtime/cgo
In file included from _cgo_export.c:3:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdlib.h:134:25: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
...

Also tried using clang to compile some random source including stdlib.h, and it did it gave out bunches of warnings almost identical to the above, however those weren't error, only warnings:

❯ clang a.c
In file included from a.c:1:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdlib.h:134:25: warning: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Wnullability-completeness]
double   atof(const char *);
...

[dust347]

I also have same problem after upgrade to catalina

export CGO_CPPFLAGS="-Wno-error -Wno-nullability-completeness -Wno-expansion-to-defined"

Maybe it can be solved

[ianlancetaylor]

I don't understand how XCode could possibly be shipping a <stdlib.h> that cannot be compiled without warnings in the default compiler setting. Can somebody investigate that? What happens if you simply compile the C program

#include <stdlib.h>

? Do you get warnings?