shell completion --format: support maps and functions

Currently we only support structs in a template string like this:
`{{.var1.test.` -> this meams that test must be a struct field on var1.

Now with this var1 and test could also be either a map or function which
returns a struct.

A actual example:
`podman container inspect  --format {{.NetworkSettings.Networks.netname.`
Now we can complete the struct fileds after netname. Note that this
cannot complete map keys since they are empty by default, so it is
impossible to get them in the completion logic.

Also this fixes a panic with embeeded nil structs
Fixes #14223

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

1 files changed, 33 insertions, 7 deletions

diff --git a/cmd/podman/common/completion_test.go b/cmd/podman/common/completion_test.go
index 34ec9b6a5..ae23b02e2 100644
--- a/cmd/podman/common/completion_test.go
+++ b/cmd/podman/common/completion_test.go
@@ -14,7 +14,14 @@ type Car struct {
 		HP           *int
 		Displacement int
 	}
-	Extras map[string]string
+	Extras map[string]Extra
+	// also ensure it will work with pointers
+	Extras2 map[string]*Extra
+}
+
+type Extra struct {
+	Name1 string
+	Name2 string
 }
 
 type Anonymous struct {
@@ -52,6 +59,10 @@ func (c Car) TwoOut() (string, string) {
 	return "", ""
 }
 
+func (c Car) Struct() Car {
+	return Car{}
+}
+
 func TestAutocompleteFormat(t *testing.T) {
 	testStruct := struct {
 		Name string
@@ -63,7 +74,6 @@ func TestAutocompleteFormat(t *testing.T) {
 	}{}
 
 	testStruct.Car = &Car{}
-	testStruct.Car.Extras = map[string]string{"test": "1"}
 
 	tests := []struct {
 		name       string
@@ -118,7 +128,7 @@ func TestAutocompleteFormat(t *testing.T) {
 		{
 			"second level struct field name",
 			"{{ .Car.",
-			[]string{"{{ .Car.Color}}", "{{ .Car.Type}}", "{{ .Car.Brand}}", "{{ .Car.Stats.", "{{ .Car.Extras}}"},
+			[]string{"{{ .Car.Color}}", "{{ .Car.Struct.", "{{ .Car.Type}}", "{{ .Car.Brand}}", "{{ .Car.Stats.", "{{ .Car.Extras.", "{{ .Car.Extras2."},
 		},
 		{
 			"second level struct field name",
@@ -128,7 +138,7 @@ func TestAutocompleteFormat(t *testing.T) {
 		{
 			"second level nil struct field name",
 			"{{ .Car2.",
-			[]string{"{{ .Car2.Color}}", "{{ .Car2.Type}}", "{{ .Car2.Brand}}", "{{ .Car2.Stats.", "{{ .Car2.Extras}}"},
+			[]string{"{{ .Car2.Color}}", "{{ .Car2.Struct.", "{{ .Car2.Type}}", "{{ .Car2.Brand}}", "{{ .Car2.Stats.", "{{ .Car2.Extras.", "{{ .Car2.Extras2."},
 		},
 		{
 			"three level struct field name",
@@ -156,20 +166,36 @@ func TestAutocompleteFormat(t *testing.T) {
 			[]string{},
 		},
 		{
+			"map values work",
+			"{{ .Car.Extras.somekey.",
+			[]string{"{{ .Car.Extras.somekey.Name1}}", "{{ .Car.Extras.somekey.Name2}}"},
+		},
+		{
+			"map values work with ptr",
+			"{{ .Car.Extras2.somekey.",
+			[]string{"{{ .Car.Extras2.somekey.Name1}}", "{{ .Car.Extras2.somekey.Name2}}"},
+		},
+		{
 			"two variables struct field name",
 			"{{ .Car.Brand }} {{ .Car.",
-			[]string{"{{ .Car.Brand }} {{ .Car.Color}}", "{{ .Car.Brand }} {{ .Car.Type}}", "{{ .Car.Brand }} {{ .Car.Brand}}",
-				"{{ .Car.Brand }} {{ .Car.Stats.", "{{ .Car.Brand }} {{ .Car.Extras}}"},
+			[]string{"{{ .Car.Brand }} {{ .Car.Color}}", "{{ .Car.Brand }} {{ .Car.Struct.", "{{ .Car.Brand }} {{ .Car.Type}}",
+				"{{ .Car.Brand }} {{ .Car.Brand}}", "{{ .Car.Brand }} {{ .Car.Stats.", "{{ .Car.Brand }} {{ .Car.Extras.",
+				"{{ .Car.Brand }} {{ .Car.Extras2."},
 		},
 		{
 			"only dot without variable",
 			".",
 			nil,
 		},
+		{
+			"access embedded nil struct field",
+			"{{.Hello.",
+			[]string{},
+		},
 	}
 
 	for _, test := range tests {
-		completion, directive := common.AutocompleteFormat(testStruct)(nil, nil, test.toComplete)
+		completion, directive := common.AutocompleteFormat(&testStruct)(nil, nil, test.toComplete)
 		// directive should always be greater than ShellCompDirectiveNoFileComp
 		assert.GreaterOrEqual(t, directive, cobra.ShellCompDirectiveNoFileComp, "unexpected ShellCompDirective")
 		assert.Equal(t, test.expected, completion, test.name)