Add a page template func

Fixes #9339

37 files changed, 350 insertions, 78 deletions

diff --git a/tpl/cast/init.go b/tpl/cast/init.go
index f1badf993..84211a00b 100644
--- a/tpl/cast/init.go
+++ b/tpl/cast/init.go
@@ -14,6 +14,8 @@
 package cast
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.ToInt,
diff --git a/tpl/collections/apply.go b/tpl/collections/apply.go
index 74ecc5b19..1dc09c8e5 100644
--- a/tpl/collections/apply.go
+++ b/tpl/collections/apply.go
@@ -40,7 +40,7 @@ func (ns *Namespace) Apply(ctx context.Context, c any, fname string, args ...any
 		return nil, errors.New("can't iterate over a nil value")
 	}
 
-	fnv, found := ns.lookupFunc(fname)
+	fnv, found := ns.lookupFunc(ctx, fname)
 	if !found {
 		return nil, errors.New("can't find function " + fname)
 	}
@@ -106,7 +106,7 @@ func applyFnToThis(ctx context.Context, fn, this reflect.Value, args ...any) (re
 	return reflect.ValueOf(nil), res[1].Interface().(error)
 }
 
-func (ns *Namespace) lookupFunc(fname string) (reflect.Value, bool) {
+func (ns *Namespace) lookupFunc(ctx context.Context, fname string) (reflect.Value, bool) {
 	namespace, methodName, ok := strings.Cut(fname, ".")
 	if !ok {
 		templ := ns.deps.Tmpl().(tpl.TemplateFuncGetter)
@@ -114,16 +114,16 @@ func (ns *Namespace) lookupFunc(fname string) (reflect.Value, bool) {
 	}
 
 	// Namespace
-	nv, found := ns.lookupFunc(namespace)
+	nv, found := ns.lookupFunc(ctx, namespace)
 	if !found {
 		return reflect.Value{}, false
 	}
 
-	fn, ok := nv.Interface().(func(...any) (any, error))
+	fn, ok := nv.Interface().(func(context.Context, ...any) (any, error))
 	if !ok {
 		return reflect.Value{}, false
 	}
-	v, err := fn()
+	v, err := fn(ctx)
 	if err != nil {
 		panic(err)
 	}
diff --git a/tpl/collections/init.go b/tpl/collections/init.go
index c992d3fb2..8801422ac 100644
--- a/tpl/collections/init.go
+++ b/tpl/collections/init.go
@@ -14,6 +14,8 @@
 package collections
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.After,
diff --git a/tpl/compare/init.go b/tpl/compare/init.go
index 98c07f41b..f080647b1 100644
--- a/tpl/compare/init.go
+++ b/tpl/compare/init.go
@@ -14,6 +14,8 @@
 package compare
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/langs"
 	"github.com/gohugoio/hugo/tpl/internal"
@@ -31,7 +33,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Default,
diff --git a/tpl/crypto/init.go b/tpl/crypto/init.go
index dddc5585a..418fbd9fb 100644
--- a/tpl/crypto/init.go
+++ b/tpl/crypto/init.go
@@ -14,6 +14,8 @@
 package crypto
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.MD5,
diff --git a/tpl/css/css.go b/tpl/css/css.go
index e1783334e..5fc613011 100644
--- a/tpl/css/css.go
+++ b/tpl/css/css.go
@@ -1,6 +1,8 @@
 package css
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/common/types/css"
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
@@ -31,7 +33,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		return ns
diff --git a/tpl/data/init.go b/tpl/data/init.go
index 22e685fc8..507e0d43e 100644
--- a/tpl/data/init.go
+++ b/tpl/data/init.go
@@ -14,6 +14,8 @@
 package data
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.GetCSV,
diff --git a/tpl/debug/init.go b/tpl/debug/init.go
index 12a99783d..796a34bfc 100644
--- a/tpl/debug/init.go
+++ b/tpl/debug/init.go
@@ -14,6 +14,8 @@
 package debug
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Dump,
diff --git a/tpl/diagrams/init.go b/tpl/diagrams/init.go
index 1ed308c57..e6356ce9c 100644
--- a/tpl/diagrams/init.go
+++ b/tpl/diagrams/init.go
@@ -15,6 +15,8 @@
 package diagrams
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -29,7 +31,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		return ns
diff --git a/tpl/encoding/init.go b/tpl/encoding/init.go
index 1d42b4e37..1c3322d6e 100644
--- a/tpl/encoding/init.go
+++ b/tpl/encoding/init.go
@@ -14,6 +14,8 @@
 package encoding
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Base64Decode,
diff --git a/tpl/fmt/init.go b/tpl/fmt/init.go
index b0683f061..8000627e2 100644
--- a/tpl/fmt/init.go
+++ b/tpl/fmt/init.go
@@ -14,6 +14,8 @@
 package fmt
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Print,
diff --git a/tpl/hugo/init.go b/tpl/hugo/init.go
index e2b4ae7af..ad589722c 100644
--- a/tpl/hugo/init.go
+++ b/tpl/hugo/init.go
@@ -15,6 +15,8 @@
 package hugo
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -27,7 +29,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return h, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return h, nil },
 		}
 
 		// We just add the Hugo struct as the namespace here. No method mappings.
diff --git a/tpl/images/init.go b/tpl/images/init.go
index d9b9af4e7..a350d5b9d 100644
--- a/tpl/images/init.go
+++ b/tpl/images/init.go
@@ -14,6 +14,8 @@
 package images
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Config,
diff --git a/tpl/inflect/init.go b/tpl/inflect/init.go
index a2d28f6bf..736e9fbd6 100644
--- a/tpl/inflect/init.go
+++ b/tpl/inflect/init.go
@@ -14,6 +14,8 @@
 package inflect
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Humanize,
diff --git a/tpl/internal/go_templates/texttemplate/hugo_template.go b/tpl/internal/go_templates/texttemplate/hugo_template.go
index 96f526005..23bc18e42 100644
--- a/tpl/internal/go_templates/texttemplate/hugo_template.go
+++ b/tpl/internal/go_templates/texttemplate/hugo_template.go
@@ -60,29 +60,29 @@ func NewExecuter(helper ExecHelper) Executer {
 }
 
 type (
-	dataContextKeyType    string
+	pageContextKeyType    string
 	hasLockContextKeyType string
 	stackContextKeyType   string
 )
 
 const (
-	// The data object passed to Execute or ExecuteWithContext gets stored with this key if not already set.
-	DataContextKey = dataContextKeyType("data")
+	// The data page passed to ExecuteWithContext gets stored with this key.
+	PageContextKey = pageContextKeyType("page")
 	// Used in partialCached to signal to nested templates that a lock is already taken.
 	HasLockContextKey = hasLockContextKeyType("hasLock")
 )
 
 // Note: The context is currently not fully implemeted in Hugo. This is a work in progress.
 func (t *executer) ExecuteWithContext(ctx context.Context, p Preparer, wr io.Writer, data any) error {
+	if ctx == nil {
+		panic("nil context")
+	}
+
 	tmpl, err := p.Prepare()
 	if err != nil {
 		return err
 	}
 
-	if v := ctx.Value(DataContextKey); v == nil {
-		ctx = context.WithValue(ctx, DataContextKey, data)
-	}
-
 	value, ok := data.(reflect.Value)
 	if !ok {
 		value = reflect.ValueOf(data)
@@ -102,28 +102,6 @@ func (t *executer) ExecuteWithContext(ctx context.Context, p Preparer, wr io.Wri
 	return tmpl.executeWithState(state, value)
 }
 
-func (t *executer) Execute(p Preparer, wr io.Writer, data any) error {
-	tmpl, err := p.Prepare()
-	if err != nil {
-		return err
-	}
-
-	value, ok := data.(reflect.Value)
-	if !ok {
-		value = reflect.ValueOf(data)
-	}
-
-	state := &state{
-		helper: t.helper,
-		prep:   p,
-		tmpl:   tmpl,
-		wr:     wr,
-		vars:   []variable{{"$", value}},
-	}
-
-	return tmpl.executeWithState(state, value)
-}
-
 // Prepare returns a template ready for execution.
 func (t *Template) Prepare() (*Template, error) {
 	return t, nil
diff --git a/tpl/internal/templatefuncsRegistry.go b/tpl/internal/templatefuncsRegistry.go
index 84e0e25fa..363f6d82f 100644
--- a/tpl/internal/templatefuncsRegistry.go
+++ b/tpl/internal/templatefuncsRegistry.go
@@ -17,6 +17,7 @@ package internal
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"go/doc"
@@ -49,7 +50,7 @@ type TemplateFuncsNamespace struct {
 	Name string
 
 	// This is the method receiver.
-	Context func(v ...any) (any, error)
+	Context func(ctx context.Context, v ...any) (any, error)
 
 	// Additional info, aliases and examples, per method name.
 	MethodMappings map[string]TemplateFuncMethodMapping
@@ -172,7 +173,7 @@ func (namespaces TemplateFuncsNamespaces) MarshalJSON() ([]byte, error) {
 		if i != 0 {
 			buf.WriteString(",")
 		}
-		b, err := ns.toJSON()
+		b, err := ns.toJSON(context.TODO())
 		if err != nil {
 			return nil, err
 		}
@@ -188,7 +189,7 @@ var ignoreFuncs = map[string]bool{
 	"Reset": true,
 }
 
-func (t *TemplateFuncsNamespace) toJSON() ([]byte, error) {
+func (t *TemplateFuncsNamespace) toJSON(ctx context.Context) ([]byte, error) {
 	var buf bytes.Buffer
 
 	godoc := getGetTplPackagesGoDoc()[t.Name]
@@ -197,11 +198,11 @@ func (t *TemplateFuncsNamespace) toJSON() ([]byte, error) {
 
 	buf.WriteString(fmt.Sprintf(`%q: {`, t.Name))
 
-	ctx, err := t.Context()
+	tctx, err := t.Context(ctx)
 	if err != nil {
 		return nil, err
 	}
-	ctxType := reflect.TypeOf(ctx)
+	ctxType := reflect.TypeOf(tctx)
 	for i := 0; i < ctxType.NumMethod(); i++ {
 		method := ctxType.Method(i)
 		if ignoreFuncs[method.Name] {
diff --git a/tpl/js/init.go b/tpl/js/init.go
index d57e0fdcb..16e6c7efa 100644
--- a/tpl/js/init.go
+++ b/tpl/js/init.go
@@ -14,6 +14,8 @@
 package js
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		return ns
diff --git a/tpl/lang/init.go b/tpl/lang/init.go
index 3f7b57ffc..62c3a56a0 100644
--- a/tpl/lang/init.go
+++ b/tpl/lang/init.go
@@ -14,6 +14,8 @@
 package lang
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/langs"
 	"github.com/gohugoio/hugo/tpl/internal"
@@ -27,7 +29,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Translate,
diff --git a/tpl/math/init.go b/tpl/math/init.go
index 19905fd3a..67aa95f41 100644
--- a/tpl/math/init.go
+++ b/tpl/math/init.go
@@ -14,6 +14,8 @@
 package math
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Add,
diff --git a/tpl/openapi/openapi3/init.go b/tpl/openapi/openapi3/init.go
index 8597e3294..4d88e148e 100644
--- a/tpl/openapi/openapi3/init.go
+++ b/tpl/openapi/openapi3/init.go
@@ -14,6 +14,8 @@
 package openapi3
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Unmarshal,
diff --git a/tpl/os/init.go b/tpl/os/init.go
index cd9e370cd..d7afba16f 100644
--- a/tpl/os/init.go
+++ b/tpl/os/init.go
@@ -14,6 +14,8 @@
 package os
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 )
@@ -26,7 +28,7 @@ func init() {
 
 		ns := &internal.TemplateFuncsNamespace{
 			Name:    name,
-			Context: func(args ...any) (any, error) { return ctx, nil },
+			Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
 		}
 
 		ns.AddMethodMapping(ctx.Getenv,
diff --git a/tpl/page/init.go b/tpl/page/init.go
new file mode 100644
index 000000000..52aeaafd6
--- /dev/null
+++ b/tpl/page/init.go
@@ -0,0 +1,49 @@
+// Copyright 2022 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package page provides template functions for accessing the current Page object,
+// the entry level context for the current template.
+package page
+
+import (
+	"context"
+
+	"github.com/gohugoio/hugo/deps"
+	"github.com/gohugoio/hugo/resources/page"
+	"github.com/gohugoio/hugo/tpl"
+
+	"github.com/gohugoio/hugo/tpl/internal"
+)