Use enumer to generate String() methods for most enums (#25705)

We have many hand-written String() methods (and similar) for enums.
These require more maintenance and are more error-prone than using
automatically generated methods. In addition, the auto-generated
versions can be more efficient.

Here, we switch to using https://github.com/loggerhead/enumer, itself
a fork of https://github.com/diegostamigni/enumer, no longer maintained,
and a fork of the mostly standard tool
https://pkg.go.dev/golang.org/x/tools/cmd/stringer.
We use this fork of enumer for Go 1.20+ compatibility and because
we require the `-transform` flag to be able to generate
constants that match our current code base.

Some enums were not targeted for this change:

api/lifetime_watcher.go

@@ -31,6 +31,7 @@ var (
 	DefaultRenewerRenewBuffer = 5
 )
 
+//go:generate enumer -type=RenewBehavior -trimprefix=RenewBehavior
 type RenewBehavior uint
 
 const (

api/plugin_runtime_types.go

@@ -9,11 +9,9 @@ package api
 
 import "fmt"
 
-var PluginRuntimeTypes = []PluginRuntimeType{
-	PluginRuntimeTypeUnsupported,
-	PluginRuntimeTypeContainer,
-}
+var PluginRuntimeTypes = _PluginRuntimeTypeValues
 
+//go:generate enumer -type=PluginRuntimeType -trimprefix=PluginRuntimeType -transform=snake
 type PluginRuntimeType uint32
 
 // This is a list of PluginRuntimeTypes used by Vault.
@@ -22,20 +20,11 @@ const (
 	PluginRuntimeTypeContainer
 )
 
-func (r PluginRuntimeType) String() string {
-	switch r {
-	case PluginRuntimeTypeContainer:
-		return "container"
-	default:
-		return "unsupported"
-	}
-}
-
+// ParsePluginRuntimeType is a wrapper around PluginRuntimeTypeString kept for backwards compatibility.
 func ParsePluginRuntimeType(PluginRuntimeType string) (PluginRuntimeType, error) {
-	switch PluginRuntimeType {
-	case "container":
-		return PluginRuntimeTypeContainer, nil
-	default:
+	t, err := PluginRuntimeTypeString(PluginRuntimeType)
+	if err != nil {
 		return PluginRuntimeTypeUnsupported, fmt.Errorf("%q is not a supported plugin runtime type", PluginRuntimeType)
 	}
+	return t, nil
 }

api/pluginruntimetype_enumer.go

@@ -0,0 +1,49 @@
+// Code generated by "enumer -type=PluginRuntimeType -trimprefix=PluginRuntimeType -transform=snake"; DO NOT EDIT.
+
+package api
+
+import (
+	"fmt"
+)
+
+const _PluginRuntimeTypeName = "unsupportedcontainer"
+
+var _PluginRuntimeTypeIndex = [...]uint8{0, 11, 20}
+
+func (i PluginRuntimeType) String() string {
+	if i >= PluginRuntimeType(len(_PluginRuntimeTypeIndex)-1) {
+		return fmt.Sprintf("PluginRuntimeType(%d)", i)
+	}
+	return _PluginRuntimeTypeName[_PluginRuntimeTypeIndex[i]:_PluginRuntimeTypeIndex[i+1]]
+}
+
+var _PluginRuntimeTypeValues = []PluginRuntimeType{0, 1}
+
+var _PluginRuntimeTypeNameToValueMap = map[string]PluginRuntimeType{
+	_PluginRuntimeTypeName[0:11]:  0,
+	_PluginRuntimeTypeName[11:20]: 1,
+}
+
+// PluginRuntimeTypeString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func PluginRuntimeTypeString(s string) (PluginRuntimeType, error) {
+	if val, ok := _PluginRuntimeTypeNameToValueMap[s]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to PluginRuntimeType values", s)
+}
+
+// PluginRuntimeTypeValues returns all values of the enum
+func PluginRuntimeTypeValues() []PluginRuntimeType {
+	return _PluginRuntimeTypeValues
+}
+
+// IsAPluginRuntimeType returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i PluginRuntimeType) IsAPluginRuntimeType() bool {
+	for _, v := range _PluginRuntimeTypeValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}

api/renewbehavior_enumer.go

@@ -0,0 +1,50 @@
+// Code generated by "enumer -type=RenewBehavior -trimprefix=RenewBehavior"; DO NOT EDIT.
+
+package api
+
+import (
+	"fmt"
+)
+
+const _RenewBehaviorName = "IgnoreErrorsRenewDisabledErrorOnErrors"
+
+var _RenewBehaviorIndex = [...]uint8{0, 12, 25, 38}
+
+func (i RenewBehavior) String() string {
+	if i >= RenewBehavior(len(_RenewBehaviorIndex)-1) {
+		return fmt.Sprintf("RenewBehavior(%d)", i)
+	}
+	return _RenewBehaviorName[_RenewBehaviorIndex[i]:_RenewBehaviorIndex[i+1]]
+}
+
+var _RenewBehaviorValues = []RenewBehavior{0, 1, 2}
+
+var _RenewBehaviorNameToValueMap = map[string]RenewBehavior{
+	_RenewBehaviorName[0:12]:  0,
+	_RenewBehaviorName[12:25]: 1,
+	_RenewBehaviorName[25:38]: 2,
+}
+
+// RenewBehaviorString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func RenewBehaviorString(s string) (RenewBehavior, error) {
+	if val, ok := _RenewBehaviorNameToValueMap[s]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to RenewBehavior values", s)
+}
+
+// RenewBehaviorValues returns all values of the enum
+func RenewBehaviorValues() []RenewBehavior {
+	return _RenewBehaviorValues
+}
+
+// IsARenewBehavior returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i RenewBehavior) IsARenewBehavior() bool {
+	for _, v := range _RenewBehaviorValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}