crypto/tls: small inconsistency around error formatting on crypto/generate_cert

[fenos]

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

$ go version go1.12.5 darwin/amd64

Does this issue reproduce with the latest release?

Yes, the inconsistency lives on the master branch

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

go env Output

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/fenos/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/fenos/Documents/code/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/Cellar/go/1.12.5/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.12.5/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
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/hd/7fyxcyhn01x2pmdqrs892v4h0000gp/T/go-build120066066=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Going trough the source code and i've noticed small inconsistencies in the code around the error formatting.

What did you expect to see?

• All errors are consistently using %s for interpolating errors
• Have the error included in every fatal error report

What did you see instead?

• using %v instead of %s https://github.com/golang/go/blob/master/src/crypto/tls/generate_cert.go#L153

• not using the interpolation correctly using the %s https://github.com/golang/go/blob/master/src/crypto/tls/generate_cert.go#L148

[fenos]

I intend to work on a fix for this

[ianlancetaylor]

Thanks for the report. It's fine to use %v to print a value of type error. If anything %v is more common than %s.

The log.Fatalf line should probably just be log.Fatal.

[gopherbot]

Change https://golang.org/cl/200679 mentions this issue: crypto/tls: Fixes #34848

[fenos]

@iamoryanmoshe yes absolutely, i'm just trying to make things consistent across the file.
Would you be happy to change all the %s to %v?

On the second bit, I think it would still be good to have the error printed out within the message