Segmentation fault when trying to create yaml out of a string

[bb-Ricardo]

Describe the bug
Hi,

I tried to generate a YAML file out of a string. Not sure if this command should work or not, but I assume it should not end in a SIGSEV.

Version of yq: 4.16.1
Operating system: OSX
Installed via: installed via homebrew

Command
The command you ran:

echo -e "a.a: a\na.b: b" | yq e -n  -s -

Actual behavior

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x124cdaf]

goroutine 1 [running]:
github.com/mikefarah/yq/v4/pkg/yqlib.(*resultsPrinter).PrintResults(0xc0001b6f50, 0xc0003f4e70)
	github.com/mikefarah/yq/v4/pkg/yqlib/printer.go:142 +0x42f
github.com/mikefarah/yq/v4/pkg/yqlib.(*streamEvaluator).Evaluate(0xc0002f5d88, {0x131f9ee, 0x1}, {0x1395780, 0xc000464660}, 0x15881c0, {0x139a3d0, 0xc0001b6f50}, {0x0, 0x0})
	github.com/mikefarah/yq/v4/pkg/yqlib/stream_evaluator.go:122 +0x446
github.com/mikefarah/yq/v4/pkg/yqlib.(*streamEvaluator).EvaluateFiles(0xc0002f5d88, {0x0, 0x0}, {0xc0002f5d48, 0x1, 0xc000141be0}, {0x139a3d0, 0xc0001b6f50}, 0x8)
	github.com/mikefarah/yq/v4/pkg/yqlib/stream_evaluator.go:72 +0x207
github.com/mikefarah/yq/v4/cmd.evaluateSequence(0xc000015680, {0xc0001138c0, 0x3, 0x3})
	github.com/mikefarah/yq/v4/cmd/evalute_sequence_command.go:116 +0x6da
github.com/spf13/cobra.(*Command).execute(0xc000015680, {0xc000113890, 0x3, 0x3})
	github.com/spf13/cobra@v1.2.1/command.go:856 +0x60e
github.com/spf13/cobra.(*Command).ExecuteC(0xc000015400)
	github.com/spf13/cobra@v1.2.1/command.go:974 +0x3bc
github.com/spf13/cobra.(*Command).Execute(...)
	github.com/spf13/cobra@v1.2.1/command.go:902
main.main()
	github.com/mikefarah/yq/v4/yq.go:11 +0x1e

Expected behavior

a:
  a: a
  b: b

Additional context
Add any other context about the problem here.

[mikefarah]

Please see this doc on syntax for creating yaml https://mikefarah.gitbook.io/yq/operators/create-collect-into-object#creating-yaml-from-scratch.

Though you have exposed a bug where yq isn't handling bad input well :)

[bb-Ricardo]

I assumed I was using it wrong, found some of this in the 2.x version doc. Solved my config creation in a different way.

But a SIGSEV was still a surprise 😀

[mikefarah]

Seg fault fixed in 4.18.1