staticcheck: SA5011 believes logrus.Fatal returns

[tendervittles]

$ staticcheck -debug.version
staticcheck (devel, v0.0.0-20191107024926-a9480a3ec3bc)

Compiled with Go version: go1.13.4
Main module:
    honnef.co/go/tools@v0.0.0-20191107024926-a9480a3ec3bc (sum: h1:G3KJU7T3tdNpGfKsED8OHHsQozNxEW0rDS785ks+feY=)
Dependencies:
    github.com/BurntSushi/toml@v0.3.1 (sum: h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=)
    golang.org/x/tools@v0.0.0-20191114222411-4191b8cbba09 (sum: h1:f3ZhcxGnJxVhcsQgKPvfAg2pjdeWBBgDuO5XfmGnoU0=)
$ go version
go version go1.13.4 linux/amd64
$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/tendervittles/.cache/go-build"
GOENV="/home/tendervittles/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/tendervittles/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/tendervittles/SA/go.mod"
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 -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build470499691=/tmp/go-build -gno-record-gcc-switches"

Ran staticcheck ./... against:

package main

import (
	"fmt"

	"github.com/sirupsen/logrus"
)

func main() {
	var x *int
	if x == nil {
		logrus.Fatal("Uh-oh")
	}
	fmt.Println(*x)
}

Staticcheck returned:

sa.go:14:14: possible nil pointer dereference (SA5011)
	sa.go:11:5: this check suggests that the pointer can be nil

This version does not trigger the warning:

package main

import (
	"fmt"
	"log"
)

func main() {
	var x *int
	if x == nil {
		log.Fatal("Uh-oh")
	}
	fmt.Println(*x)
}

[dominikh]

The issue is that logrus.Fatal does not unconditionally terminate the process, as it relies on logrus.Logger.ExitFunc – which may be any function.

I think my only choice is to add a special case for logrus.

[mpictor]

It'd be nice to have some sort of annotation we could add to functions to tell the analyzer to treat them as non-returning. I'm seeing the same linter error, SA5011, with a call to an in-house logging package's Fatal() function. As with logrus, the actual behavior depends on a function variable.

Clang-analyzer uses __attribute__((analyzer_noreturn)) to emphasize that the attribute impacts analysis only and not compilation, as opposed to the GCC attribute noreturn.

Would it be possible to detect a comment line like // analyzer_noreturn when it's the last (or only) line of a function's block comment, then mark the function as noreturn?

[dominikh]

I'm thinking about it.