Implement webhook branch filter (#7791)

* Fix validate() function to handle errors in embedded anon structs

* Implement webhook branch filter

See #2025, #3998.

vendor/github.com/gobwas/glob/syntax/ast/ast.go

@@ -0,0 +1,122 @@
+package ast
+
+import (
+	"bytes"
+	"fmt"
+)
+
+type Node struct {
+	Parent   *Node
+	Children []*Node
+	Value    interface{}
+	Kind     Kind
+}
+
+func NewNode(k Kind, v interface{}, ch ...*Node) *Node {
+	n := &Node{
+		Kind:  k,
+		Value: v,
+	}
+	for _, c := range ch {
+		Insert(n, c)
+	}
+	return n
+}
+
+func (a *Node) Equal(b *Node) bool {
+	if a.Kind != b.Kind {
+		return false
+	}
+	if a.Value != b.Value {
+		return false
+	}
+	if len(a.Children) != len(b.Children) {
+		return false
+	}
+	for i, c := range a.Children {
+		if !c.Equal(b.Children[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+func (a *Node) String() string {
+	var buf bytes.Buffer
+	buf.WriteString(a.Kind.String())
+	if a.Value != nil {
+		buf.WriteString(" =")
+		buf.WriteString(fmt.Sprintf("%v", a.Value))
+	}
+	if len(a.Children) > 0 {
+		buf.WriteString(" [")
+		for i, c := range a.Children {
+			if i > 0 {
+				buf.WriteString(", ")
+			}
+			buf.WriteString(c.String())
+		}
+		buf.WriteString("]")
+	}
+	return buf.String()
+}
+
+func Insert(parent *Node, children ...*Node) {
+	parent.Children = append(parent.Children, children...)
+	for _, ch := range children {
+		ch.Parent = parent
+	}
+}
+
+type List struct {
+	Not   bool
+	Chars string
+}
+
+type Range struct {
+	Not    bool
+	Lo, Hi rune
+}
+
+type Text struct {
+	Text string
+}
+
+type Kind int
+
+const (
+	KindNothing Kind = iota
+	KindPattern
+	KindList
+	KindRange
+	KindText
+	KindAny
+	KindSuper
+	KindSingle
+	KindAnyOf
+)
+
+func (k Kind) String() string {
+	switch k {
+	case KindNothing:
+		return "Nothing"
+	case KindPattern:
+		return "Pattern"
+	case KindList:
+		return "List"
+	case KindRange:
+		return "Range"
+	case KindText:
+		return "Text"
+	case KindAny:
+		return "Any"
+	case KindSuper:
+		return "Super"
+	case KindSingle:
+		return "Single"
+	case KindAnyOf:
+		return "AnyOf"
+	default:
+		return ""
+	}
+}