Pulsar: "incompatible pointer types" warnings building the Go (golang) pulsar client

[simoneau]

Describe the bug
When building with the Go Pulsar client, I always see about 10 warnings about incompatible pointer types. Is this a known issue?

To Reproduce
Steps to reproduce the behavior:

1. ❯ go get -u github.com/apache/pulsar/pulsar-client-go/pulsar
2. See warnings

Screenshots

GOROOT=/usr/local/Cellar/go/1.13.1/libexec #gosetup
GOPATH=/Users/matthew/go #gosetup
/usr/local/Cellar/go/1.13.1/libexec/bin/go build -o /private/var/folders/z0/f6_lcbw12y74t8hr_zfxr3zr0000gp/T/___ambassador github.com/ETMAInc/platform/services/ambassador #gosetup
# github.com/apache/pulsar/pulsar-client-go/pulsar
In file included from _cgo_export.c:4:
In file included from c_client.go:24:
../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_go_pulsar.h:75:51: warning: incompatible pointer types passing 'void (pulsar_result, pulsar_message_id_t *, void *)' (aka 'void (pulsar_result, struct _pulsar_message_id *, void *)') to parameter of type 'pulsar_send_callback' (aka 'void (*)(pulsar_result, struct _pulsar_message *, void *)') [-Wincompatible-pointer-types]
/usr/local/include/pulsar/c/producer.h:81:68: note: passing argument to parameter 'callback' here
# github.com/apache/pulsar/pulsar-client-go/pulsar
In file included from ../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_client.go:24:
../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_go_pulsar.h:75:51: warning: incompatible pointer types passing 'void (pulsar_result, pulsar_message_id_t *, void *)' (aka 'void (pulsar_result, struct _pulsar_message_id *, void *)') to parameter of type 'pulsar_send_callback' (aka 'void (*)(pulsar_result, struct _pulsar_message *, void *)') [-Wincompatible-pointer-types]
/usr/local/include/pulsar/c/producer.h:81:68: note: passing argument to parameter 'callback' here
# github.com/apache/pulsar/pulsar-client-go/pulsar
In file included from ../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_consumer.go:23:
../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_go_pulsar.h:75:51: warning: incompatible pointer types passing 'void (pulsar_result, pulsar_message_id_t *, void *)' (aka 'void (pulsar_result, struct _pulsar_message_id *, void *)') to parameter of type 'pulsar_send_callback' (aka 'void (*)(pulsar_result, struct _pulsar_message *, void *)') [-Wincompatible-pointer-types]
/usr/local/include/pulsar/c/producer.h:81:68: note: passing argument to parameter 'callback' here
# github.com/apache/pulsar/pulsar-client-go/pulsar
In file included from ../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_error.go:25:
../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_go_pulsar.h:75:51: warning: incompatible pointer types passing 'void (pulsar_result, pulsar_message_id_t *, void *)' (aka 'void (pulsar_result, struct _pulsar_message_id *, void *)') to parameter of type 'pulsar_send_callback' (aka 'void (*)(pulsar_result, struct _pulsar_message *, void *)') [-Wincompatible-pointer-types]
/usr/local/include/pulsar/c/producer.h:81:68: note: passing argument to parameter 'callback' here
# github.com/apache/pulsar/pulsar-client-go/pulsar
In file included from ../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_message.go:23:
../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_go_pulsar.h:75:51: warning: incompatible pointer types passing 'void (pulsar_result, pulsar_message_id_t *, void *)' (aka 'void (pulsar_result, struct _pulsar_message_id *, void *)') to parameter of type 'pulsar_send_callback' (aka 'void (*)(pulsar_result, struct _pulsar_message *, void *)') [-Wincompatible-pointer-types]
/usr/local/include/pulsar/c/producer.h:81:68: note: passing argument to parameter 'callback' here
# github.com/apache/pulsar/pulsar-client-go/pulsar
In file included from ../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_producer.go:23:
../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_go_pulsar.h:75:51: warning: incompatible pointer types passing 'void (pulsar_result, pulsar_message_id_t *, void *)' (aka 'void (pulsar_result, struct _pulsar_message_id *, void *)') to parameter of type 'pulsar_send_callback' (aka 'void (*)(pulsar_result, struct _pulsar_message *, void *)') [-Wincompatible-pointer-types]
/usr/local/include/pulsar/c/producer.h:81:68: note: passing argument to parameter 'callback' here
# github.com/apache/pulsar/pulsar-client-go/pulsar
In file included from ../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_reader.go:23:
../../../../go/pkg/mod/github.com/apache/pulsar/[email protected]/pulsar/c_go_pulsar.h:75:51: warning: incompatible pointer types passing 'void (pulsar_result, pulsar_message_id_t *, void *)' (aka 'void (pulsar_result, struct _pulsar_message_id *, void *)') to parameter of type 'pulsar_send_callback' (aka 'void (*)(pulsar_result, struct _pulsar_message *, void *)') [-Wincompatible-pointer-types]
/usr/local/include/pulsar/c/producer.h:81:68: note: passing argument to parameter 'callback' here

Desktop (please complete the following information):

• OS: macOS, LInux

[wolfstudy]

Is this a known issue?

Yes, this is a known issue. This does not affect normal use. The issue was caused by the introduction of the SendAndGetMsgID interface.

[fredczj]

Would it be possible to fix this known message, please?
This would clean the build message a lot !

[bschofield]

Workaround: edit pulsar/c_client.go and just before the line beginning #include, add:

#cgo CFLAGS: -Wno-incompatible-pointer-types