defaultFlags is ignored

[rh-hemartin]

Hello! I'm trying to use defaultFlags but it looks like its ignored.

Here the reproducer:

mkdir ko-reproducer
cd ko-reproducer

cat <<EOF > main.go
package main

import "fmt"

func main() {
        fmt.Println("Hello World!")
}
EOF
go mod init example.com
go mod tidy
go build -cover .
GOCOVERDIR=hello ./example.com

This results in this error:

error: coverage meta-data emit failed: output directory "hello" inaccessible (err: stat hello: no such file or directory); no coverage data written
Hello World!
error: coverage counter data emit failed: output directory "hello" inaccessible (err: stat hello: no such file or directory); no coverage data written

Now with ko:

cat <<EOF > .ko.yaml
---
defaultFlags:
  - -cover
EOF

KOCACHE=kocache ko build . --push=false
GOCOVERDIR=hello ./kocache/bin/example.com/linux/amd64/out

Does not fail:

Hello World!

Now using "normal" flags:

cat <<EOF > .ko.yaml
---
builds:
- id: main
  main: ./
  flags:
    - -cover
EOF

rm -rf ./kocache
KOCACHE=kocache ko build . --push=false
GOCOVERDIR=hello ./kocache/bin/example.com/linux/amd64/out

error: coverage meta-data emit failed: output directory "hello" inaccessible (err: stat hello: no such file or directory); no coverage data written
Hello World!
error: coverage counter data emit failed: output directory "hello" inaccessible (err: stat hello: no such file or directory); no coverage data written

PD: I tested introducing a random string into defaultFlags and it does not fail, so its effectively ignored.
PD2: I can give it a go and try to fix it myself, but I want someone to confirm it first.