Support constant values of enum aliased types (#79)

This adds support for extracting information about constant values
of alias types used to simulate enumerations.

processor/processor.go

@@ -19,6 +19,8 @@ package processor
 
 import (
 	"fmt"
+	"go/ast"
+	"go/token"
 	gotypes "go/types"
 	"regexp"
 	"sort"
@@ -327,6 +329,9 @@ func (p *processor) processType(pkg *loader.Package, parentType *types.Type, t g
 		if info != nil {
 			underlying = pkg.TypesInfo.TypeOf(info.RawSpec.Type)
 		}
+		if underlying.String() == "string" {
+			typeDef.EnumValues = lookupConstantValuesForAliasedType(pkg, typeDef.Name)
+		}
 		typeDef.UnderlyingType = p.processType(pkg, typeDef, underlying, depth+1)
 		p.addReference(typeDef, typeDef.UnderlyingType)
 
@@ -570,3 +575,37 @@ func (p *processor) parseMarkers() {
 		}
 	}
 }
+
+func lookupConstantValuesForAliasedType(pkg *loader.Package, aliasTypeName string) []types.EnumValue {
+	values := []types.EnumValue{}
+	for _, file := range pkg.Syntax {
+		for _, decl := range file.Decls {
+			node, ok := decl.(*ast.GenDecl)
+			if !ok || node.Tok != token.CONST {
+				continue
+			}
+			for _, spec := range node.Specs {
+				// look for constant declaration
+				v, ok := spec.(*ast.ValueSpec)
+				if !ok {
+					continue
+				}
+				// value type must match the alias type name and have exactly one value
+				if id, ok := v.Type.(*ast.Ident); !ok || id.String() != aliasTypeName || len(v.Values) != 1 {
+					continue
+				}
+				// convert to a basic type to access to the value
+				b, ok := v.Values[0].(*ast.BasicLit)
+				if !ok {
+					continue
+				}
+				values = append(values, types.EnumValue{
+					// remove the '"' signs from the start and end of the value
+					Name: b.Value[1 : len(b.Value)-1],
+					Doc:  v.Doc.Text(),
+				})
+			}
+		}
+	}
+	return values
+}

templates/markdown/type.tpl

@@ -36,5 +36,13 @@ _Appears in:_
 
 {{ end -}}
 
+{{ if $type.EnumValues -}} 
+| Field | Description |
+{{ range $type.EnumValues -}}
+| `{{ .Name }}` | {{ markdownRenderFieldDoc .Doc }} |
+{{ end -}}
+{{ end -}}
+
+
 {{- end -}}
 {{- end -}}

test/api/v1/guestbook_types.go

@@ -98,8 +98,20 @@ type GuestbookSpec struct {
 	// CertificateRef is a reference to a secret containing a certificate
 	CertificateRef gwapiv1b1.SecretObjectReference `json:"certificateRef"`
 	String         common.CommonString             `json:"str"`
+	// Enumeration is an example of an aliased enumeration type
+	Enumeration MyEnum `json:"enum"`
 }
 
+// +kubebuilder:validation:Enum=MyFirstValue;MySecondValue
+type MyEnum string
+
+const (
+	// MyFirstValue is an interesting value to use
+	MyFirstValue MyEnum = "MyFirstValue"
+	// MySecondValue is what you use when you can't use MyFirstValue
+	MySecondValue MyEnum = "MySecondValue"
+)
+
 // +kubebuilder:validation:Minimum=1
 type PositiveInt int
 

test/expected.asciidoc

@@ -243,11 +243,30 @@ UniqueItems: true +
 
 | *`certificateRef`* __link:https://gateway-api.sigs.k8s.io/references/spec/#gateway.networking.k8s.io/v1beta1.SecretObjectReference[$$SecretObjectReference$$]__ | CertificateRef is a reference to a secret containing a certificate + |  | 
 | *`str`* __xref:{anchor_prefix}-github-com-elastic-crd-ref-docs-api-common-commonstring[$$CommonString$$]__ |  |  | 
+| *`enum`* __xref:{anchor_prefix}-github-com-elastic-crd-ref-docs-api-v1-myenum[$$MyEnum$$]__ | Enumeration is an example of an aliased enumeration type + |  | Enum: [MyFirstValue MySecondValue] +
+
 |===
 
 
 
 
+[id="{anchor_prefix}-github-com-elastic-crd-ref-docs-api-v1-myenum"]
+==== MyEnum
+
+_Underlying type:_ _string_
+
+
+
+.Validation:
+- Enum: [MyFirstValue MySecondValue]
+
+.Appears In:
+****
+- xref:{anchor_prefix}-github-com-elastic-crd-ref-docs-api-v1-guestbookspec[$$GuestbookSpec$$]
+****
+
+
+
 [id="{anchor_prefix}-github-com-elastic-crd-ref-docs-api-v1-positiveint"]
 ==== PositiveInt
 

test/expected.md

@@ -180,10 +180,28 @@ _Appears in:_
 | `headers` _[GuestbookHeader](#guestbookheader) array_ | Headers contains a list of header items to include in the page |  | MaxItems: 10 <br />UniqueItems: true <br /> |
 | `certificateRef` _[SecretObjectReference](https://gateway-api.sigs.k8s.io/references/spec/#gateway.networking.k8s.io/v1beta1.SecretObjectReference)_ | CertificateRef is a reference to a secret containing a certificate |  |  |
 | `str` _[CommonString](#commonstring)_ |  |  |  |
+| `enum` _[MyEnum](#myenum)_ | Enumeration is an example of an aliased enumeration type |  | Enum: [MyFirstValue MySecondValue] <br /> |
 
 
 
 
+#### MyEnum
+
+_Underlying type:_ _string_
+
+
+
+_Validation:_
+- Enum: [MyFirstValue MySecondValue]
+
+_Appears in:_
+- [GuestbookSpec](#guestbookspec)
+
+| Field | Description |
+| `MyFirstValue` | MyFirstValue is an interesting value to use<br /> |
+| `MySecondValue` | MySecondValue is what you use when you can't use MyFirstValue<br /> |
+
+
 #### PositiveInt
 
 _Underlying type:_ _integer_

test/hide.md

@@ -52,11 +52,8 @@ Package v1 contains API Schema definitions for the webapp v1 API group
 | --- | --- | --- | --- |
 | `apiVersion` _string_ | `webapp.test.k8s.elastic.co/v1` | | |
 | `kind` _string_ | `Embedded` | | |
-
 | `metadata` _[ObjectMeta](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.25/#objectmeta-v1-meta)_ | Refer to Kubernetes API documentation for fields of `metadata`. |  |  |
-
 | `a` _string_ |  |  |  |
-
 | `x` _string_ |  |  |  |
 
 
@@ -73,7 +70,6 @@ _Appears in:_
 
 | Field | Description | Default | Validation |
 | --- | --- | --- | --- |
-
 | `x` _string_ |  |  |  |
 
 
@@ -91,7 +87,6 @@ _Appears in:_
 
 | Field | Description | Default | Validation |
 | --- | --- | --- | --- |
-
 | `x` _string_ |  |  |  |
 
 
@@ -110,9 +105,7 @@ _Appears in:_
 | --- | --- | --- | --- |
 | `apiVersion` _string_ | `webapp.test.k8s.elastic.co/v1` | | |
 | `kind` _string_ | `Guestbook` | | |
-
 | `metadata` _[ObjectMeta](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.25/#objectmeta-v1-meta)_ | Refer to Kubernetes API documentation for fields of `metadata`. |  |  |
-
 | `spec` _[GuestbookSpec](#guestbookspec)_ |  | \{ page:1 \} |  |
 
 
@@ -129,13 +122,9 @@ _Appears in:_
 
 | Field | Description | Default | Validation |
 | --- | --- | --- | --- |
-
 | `name` _string_ | Name of the guest (pipe \| should be escaped) |  | MaxLength: 80 <br />Pattern: `0*[a-z0-9]*[a-z]*[0-9]` <br /> |
-
 | `time` _[Time](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.25/#time-v1-meta)_ | Time of entry |  |  |
-
 | `comment` _string_ | Comment by guest. This can be a multi-line comment.<br />Like this one.<br />Now let's test a list:<br />* a<br />* b<br /><br />Another isolated comment.<br /><br />Looks good? |  | Pattern: `0*[a-z0-9]*[a-z]*[0-9]*` <br /> |
-
 | `rating` _[Rating](#rating)_ | Rating provided by the guest |  | Maximum: 5 <br />Minimum: 1 <br /> |
 
 
@@ -166,9 +155,7 @@ GuestbookList contains a list of Guestbook.
 | --- | --- | --- | --- |
 | `apiVersion` _string_ | `webapp.test.k8s.elastic.co/v1` | | |
 | `kind` _string_ | `GuestbookList` | | |
-
 | `metadata` _[ListMeta](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.25/#listmeta-v1-meta)_ | Refer to Kubernetes API documentation for fields of `metadata`. |  |  |
-
 | `items` _[Guestbook](#guestbook) array_ |  |  |  |
 
 
@@ -185,21 +172,33 @@ _Appears in:_
 
 | Field | Description | Default | Validation |
 | --- | --- | --- | --- |
-
 | `page` _[PositiveInt](#positiveint)_ | Page indicates the page number | 1 | Minimum: 1 <br /> |
-
 | `entries` _[GuestbookEntry](#guestbookentry) array_ | Entries contain guest book entries for the page |  |  |
-
 | `selector` _[LabelSelector](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.25/#labelselector-v1-meta)_ | Selector selects something |  |  |
-
 | `headers` _[GuestbookHeader](#guestbookheader) array_ | Headers contains a list of header items to include in the page |  | MaxItems: 10 <br />UniqueItems: true <br /> |
-
 | `certificateRef` _[SecretObjectReference](https://gateway-api.sigs.k8s.io/references/spec/#gateway.networking.k8s.io/v1beta1.SecretObjectReference)_ | CertificateRef is a reference to a secret containing a certificate |  |  |
-
 | `str` _[CommonString](#commonstring)_ |  |  |  |
+| `enum` _[MyEnum](#myenum)_ | Enumeration is an example of an aliased enumeration type |  | Enum: [MyFirstValue MySecondValue] <br /> |
+
+
+
+
+#### MyEnum
+
+_Underlying type:_ _string_
 
 
 
+_Validation:_
+- Enum: [MyFirstValue MySecondValue]
+
+_Appears in:_
+- [GuestbookSpec](#guestbookspec)
+
+| Field | Description |
+| `MyFirstValue` | MyFirstValue is an interesting value to use<br /> |
+| `MySecondValue` | MySecondValue is what you use when you can't use MyFirstValue<br /> |
+
 
 #### PositiveInt
 
@@ -246,9 +245,7 @@ Underlying tests that Underlying1's underlying type is Underlying2 instead of st
 | --- | --- | --- | --- |
 | `apiVersion` _string_ | `webapp.test.k8s.elastic.co/v1` | | |
 | `kind` _string_ | `Underlying` | | |
-
 | `metadata` _[ObjectMeta](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.25/#objectmeta-v1-meta)_ | Refer to Kubernetes API documentation for fields of `metadata`. |  |  |
-
 | `a` _[Underlying1](#underlying1)_ |  | b | MaxLength: 10 <br /> |
 
 

test/templates/markdown/type.tpl

@@ -32,12 +32,18 @@ _Appears in:_
 
 {{ range $type.Members -}}
 {{ with .Markers.hidefromdoc -}}
-{{ else }}
+{{ else -}}
 | `{{ .Name  }}` _{{ markdownRenderType .Type }}_ | {{ template "type_members" . }} | {{ markdownRenderDefault .Default }} | {{ range .Validation -}} {{ . }} <br />{{ end }} |
 {{ end -}}
 {{ end -}}
 
 {{ end -}}
 
+{{ if $type.EnumValues -}}
+| Field | Description |
+{{ range $type.EnumValues -}}
+| `{{ .Name }}` | {{ markdownRenderFieldDoc .Doc }} |
+{{ end -}}
+{{ end -}}
 {{- end -}}
 {{- end -}}

types/types.go

@@ -110,6 +110,7 @@ type Type struct {
 	ValueType      *Type                    `json:"valueType"`      // for maps
 	Fields         Fields                   `json:"fields"`         // for structs
 	References     []*Type                  `json:"-"`              // other types that refer to this type
+	EnumValues     []EnumValue              `json:"enumValues"`     // for enum values of aliased string types
 }
 
 func (t *Type) IsBasic() bool {
@@ -369,3 +370,9 @@ func (gvd GroupVersionDetails) SortedKinds() []string {
 
 	return kindsList
 }
+
+// EnumValue describes a constant value for enumerations
+type EnumValue struct {
+	Name string
+	Doc  string
+}