yq crashes when piping a yaml file with another yaml file as input

[hickersonj]

Describe the bug
When piping a file to yq as one input with another file as the other input there is a runtime error. However, providing the two files as arguments works.

Version of yq: 4.24.5
Operating system: Linux (Fedora 33)
Installed via: binary release

Input Yaml
Concise yaml document(s) (as simple as possible to show the bug, please keep it to 10 lines or less)
namespace.yml

---
apiVersion: v1
kind: Namespace
metadata:
  name: namespace

app.yml

---
apiVersion: v1
kind: Deployment
metadata:
  name: deploy-app
  labels:
    app: deploy-label
---
apiVersion: v1
kind: Daemonset
metadata:
  name: daemonset-app
  labels:
    app: daemonset-label

Command

cat namespace.yml | yq eval-all 'with(select(fi == 0); .metadata.name = env(Namespace)) | with(select(fi != 0); .metadata += {"namespace": env(Namespace)})' app.yml -

Actual behavior

panic: runtime error: index out of range [2] with length 2

goroutine 1 [running]:
github.com/mikefarah/yq/v4/pkg/yqlib.addMaps(0xc0003eb9d0, 0xc0003feba0?, 0xc0003e1a80?)
	/home/runner/work/yq/yq/pkg/yqlib/operator_add.go:193 +0x3af
github.com/mikefarah/yq/v4/pkg/yqlib.add(0xc0000a1800?, {0xc0004020c0, 0xc000397860, 0x1, {0x0, 0x0}}, 0xc0003eb500, 0xc0003eb960)
	/home/runner/work/yq/yq/pkg/yqlib/operator_add.go:63 +0x539
github.com/mikefarah/yq/v4/pkg/yqlib.resultsForRHS(0x19?, {0xc0004020c0, 0xc000397860, 0x1, {0x0, 0x0}}, 0x203000?, {0x0, 0x0, 0x7d7740}, ...)
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:88 +0x503
github.com/mikefarah/yq/v4/pkg/yqlib.doCrossFunc(0x22?, {0xc0004020c0, 0xc000397860, 0x1, {0x0, 0x0}}, 0xc00037e7c8, {0x0, 0x0, 0x7d7740})
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:125 +0x413
github.com/mikefarah/yq/v4/pkg/yqlib.crossFunctionWithPrefs(0x1?, {0xc0004020c0, 0xc000397860, 0x1, {0x0, 0x0}}, 0xc000397f50?, {0x0, 0x0, 0x7d7740})
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:152 +0x212
github.com/mikefarah/yq/v4/pkg/yqlib.crossFunction(0xc0000a1800?, {0xc0004020c0, 0xc000397860, 0x1, {0x0, 0x0}}, 0x0?, 0xaeb540?, 0x0?)
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:136 +0x9f
github.com/mikefarah/yq/v4/pkg/yqlib.addOperator(0xc0000a1800?, {0xc000397da0, 0xc000397860, 0x1, {0x0, 0x0}}, 0x0?)
	/home/runner/work/yq/yq/pkg/yqlib/operator_add.go:46 +0x1c5
github.com/mikefarah/yq/v4/pkg/yqlib.(*dataTreeNavigator).GetMatchingNodes(0xc000397860?, {0xc000397da0, 0xc000397860, 0x1, {0x0, 0x0}}, 0xc00037e7c8)
	/home/runner/work/yq/yq/pkg/yqlib/data_tree_navigator.go:37 +0x25c
github.com/mikefarah/yq/v4/pkg/yqlib.resultsForRHS(0x19?, {0xc000397da0, 0xc000397860, 0x1, {0x0, 0x0}}, 0x203000?, {0x0, 0x0, 0xc0003e1980}, ...)
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:69 +0x1fc
github.com/mikefarah/yq/v4/pkg/yqlib.doCrossFunc(0x22?, {0xc000397da0, 0xc000397860, 0x1, {0x0, 0x0}}, 0xc00037e7e0, {0x0, 0x0, 0xc0003e1980})
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:125 +0x413
github.com/mikefarah/yq/v4/pkg/yqlib.crossFunctionWithPrefs(0x1?, {0xc000397da0, 0xc000397860, 0x1, {0x0, 0x0}}, 0x7f82cdaf95b8?, {0x0, 0x0, 0xc0003e1980})
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:152 +0x212
github.com/mikefarah/yq/v4/pkg/yqlib.crossFunction(0xc0003d2df8?, {0xc000397da0, 0xc000397860, 0x1, {0x0, 0x0}}, 0xc00037e7b0?, 0xc0003d2e60?, 0xf?)
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:136 +0x9f
github.com/mikefarah/yq/v4/pkg/yqlib.assignUpdateOperator(0xc0000a1800?, {0xc0003977d0, 0xc000397860, 0x0, {0x0, 0x0}}, 0xc00037e7e0)
	/home/runner/work/yq/yq/pkg/yqlib/operator_assign.go:31 +0x305
github.com/mikefarah/yq/v4/pkg/yqlib.(*dataTreeNavigator).GetMatchingNodes(0xc00037e798?, {0xc0003977d0, 0xc000397860, 0x0, {0x0, 0x0}}, 0xc00037e7e0)
	/home/runner/work/yq/yq/pkg/yqlib/data_tree_navigator.go:37 +0x25c
github.com/mikefarah/yq/v4/pkg/yqlib.compoundAssignFunction(0x4cf825?, {0xc0003977d0, 0xc000397860, 0x0, {0x0, 0x0}}, 0xc00037e5d0, 0x7d7820)
	/home/runner/work/yq/yq/pkg/yqlib/operators.go:35 +0x3ba
github.com/mikefarah/yq/v4/pkg/yqlib.addAssignOperator(0xc0000a1800?, {0xc0003977d0, 0xc000397860, 0x0, {0x0, 0x0}}, 0x0?)
	/home/runner/work/yq/yq/pkg/yqlib/operator_add.go:19 +0x94
github.com/mikefarah/yq/v4/pkg/yqlib.(*dataTreeNavigator).GetMatchingNodes(0xc0000a1800?, {0xc0003977d0, 0xc000397860, 0x0, {0x0, 0x0}}, 0xc00037e5d0)
	/home/runner/work/yq/yq/pkg/yqlib/data_tree_navigator.go:37 +0x25c
github.com/mikefarah/yq/v4/pkg/yqlib.withOperator(0xc0000a1800?, {0xc0002f7080, 0x0, 0x0, {0x0, 0x0}}, 0xc00037e600)
	/home/runner/work/yq/yq/pkg/yqlib/operator_with.go:25 +0x34c
github.com/mikefarah/yq/v4/pkg/yqlib.(*dataTreeNavigator).GetMatchingNodes(0x46af9e?, {0xc0002f7080, 0x0, 0x0, {0x0, 0x0}}, 0xc00037e600)
	/home/runner/work/yq/yq/pkg/yqlib/data_tree_navigator.go:37 +0x25c
github.com/mikefarah/yq/v4/pkg/yqlib.pipeOperator(0xc0000a1800?, {0xc0002f7080, 0x0, 0x0, {0x0, 0x0}}, 0xc00037e618)
	/home/runner/work/yq/yq/pkg/yqlib/operator_pipe.go:13 +0x147
github.com/mikefarah/yq/v4/pkg/yqlib.(*dataTreeNavigator).GetMatchingNodes(0xc0003902a0?, {0xc0002f7080, 0x0, 0x0, {0x0, 0x0}}, 0xc00037e618)
	/home/runner/work/yq/yq/pkg/yqlib/data_tree_navigator.go:37 +0x25c
github.com/mikefarah/yq/v4/pkg/yqlib.(*allAtOnceEvaluator).EvaluateCandidateNodes(0xc0003d3ca8, {0x7fffa10a18cf?, 0x7fffa10a1952?}, 0xc0002f7080)
	/home/runner/work/yq/yq/pkg/yqlib/all_at_once_evaluator.go:42 +0xba
github.com/mikefarah/yq/v4/pkg/yqlib.(*allAtOnceEvaluator).EvaluateFiles(0x7b1cdb?, {0x7fffa10a18cf, 0x7a}, {0xc0000a1cc0, 0x2, 0xc0000c4f28?}, {0x838cb0, 0xc00038e180}, 0x1, {0x838220, ...})
	/home/runner/work/yq/yq/pkg/yqlib/all_at_once_evaluator.go:85 +0x35d
github.com/mikefarah/yq/v4/cmd.evaluateAll(0xc0000cb680?, {0xc0000a1cb0?, 0x3, 0x3})
	/home/runner/work/yq/yq/cmd/evaluate_all_command.go:144 +0x137e
github.com/spf13/cobra.(*Command).execute(0xc0000cb680, {0xc0000a1c80, 0x3, 0x3})
	/home/runner/go/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:856 +0x67c
github.com/spf13/cobra.(*Command).ExecuteC(0xc0000cb180)
	/home/runner/go/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:974 +0x3b4
github.com/spf13/cobra.(*Command).Execute(...)
	/home/runner/go/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:902
main.main()
	/home/runner/work/yq/yq/yq.go:22 +0x1f1

Expected behavior

---
apiVersion: v1
kind: Namespace
metadata:
  name: app-test
---
apiVersion: v1
kind: Deployment
metadata:
  name: deploy-app
  labels:
    app: deploy-label
  namespace: app-test
---
apiVersion: v1
kind: Daemonset
metadata:
  name: daemonset-app
  labels:
    app: daemonset-label
  namespace: app-test

Additional context
The goal is to append the Namespace resource to the app.yml without needing to have seperate files, i.e. the namespace.yml would be piped into yq inside of a bash script.

[mikefarah]

Ok I found the bug - it's with appending to a map when the new key entry matches a value in an existing map (in this case namespace). I'll have a fix in the next release, till then, as a workaround, instead of .metadata += {"namespace": env(Namespace)} just do .metadata.namespace = env(Namespace)

[hickersonj]

Glad you found the bug quickly! Also I didn't know that syntax .metadata.namespace = env(Namespace) would add a key value pair, glad to have learned that.

It is now working with the suggestions thanks.

[mikefarah]

Fixed in 4.25.1