Issue: failed to parse profiles: line...doesn't match expected format: couldn't find a before

[devplayerJoe]

Go version (go version)?

$ go version
go version go1.13.9 darwin/amd64

Details about the operating system and processor architecture (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="$HOME/Library/Caches/go-build"
GOENV="$HOME/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="$HOME/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="$HOME/go/project1/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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/nt/gc7658bs1132ttlcjdmlwwxm0000gn/T/go-build221587211=/tmp/go-build -gno-record-gcc-switches -fno-common"

Problem statement

I am generating respective coverage files for each _test.go file. However, I am getting an error while executing the gocovmerge command from last few days. I first encountered it on 25 March, then on 26-27 March, it worked fine. But again from 28-29 March, I am facing the same issue again.

Executed below command to generate merged coverage profile file

gocovmerge ${coverageDir}/myTest-*-coverage.profile

Expected outcome?

Merged coverage profile file being generated without any error

Observed output?

2021/03/30 01:43:34 failed to parse profiles: line "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" doesn't match expected format: couldn't find a   before Count

Kindly assist in nailing down the issue.

[devplayerJoe]

@wadey, could you please assist?

[wadey]

Check all of your myTest-*-coverage.profile files, it looks like one of them has invalid binary data in it (zero bytes). These should all be text files and not contain zero bytes.

[devplayerJoe]

Got one coverage file having binary data. There are 40 ish test patterns for unit tests and all of them are creating separate coverage profile file ${profileName}.profile with command:
go test -p 1 -cover -v ./${pkgName} -run ${pattern} -coverprofile=${profileName}.profile ./${pkgName}
All other files are 1M in size and only file containing binary data in end has size 148K.
Any pointers on why it could happen?

[wadey]

Perhaps the go test run is failing or calling os.Exit incorrectly? I would regenerate all of your .profile files to see which one is the issue and then investigate that test suite to see why it's being generated incorrectly.