Improve error messages, esp. when the server is running

* Add file context to minifier errors when publishing
* Misc fixes (see issues)
* Allow custom server error template in layouts/server/error.html

To get to this, this commit also cleans up and simplifies the code surrounding errors and files. This also removes the usage of `github.com/pkg/errors`, mostly because of https://github.com/pkg/errors/issues/223 -- but also because most of this is now built-in to Go.

Fixes #9852
Fixes #9857
Fixes #9863

tpl/collections/collections.go

@@ -24,12 +24,13 @@ import (
 	"strings"
 	"time"
 
+	"errors"
+
 	"github.com/gohugoio/hugo/common/collections"
 	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/common/types"
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/helpers"
-	"github.com/pkg/errors"
 	"github.com/spf13/cast"
 )
 
@@ -736,7 +737,7 @@ func (ns *Namespace) Uniq(seq any) (any, error) {
 	case reflect.Array:
 		slice = reflect.MakeSlice(reflect.SliceOf(v.Type().Elem()), 0, 0)
 	default:
-		return nil, errors.Errorf("type %T not supported", seq)
+		return nil, fmt.Errorf("type %T not supported", seq)
 	}
 
 	seen := make(map[any]bool)

tpl/collections/merge.go

@@ -14,13 +14,14 @@
 package collections
 
 import (
+	"fmt"
 	"reflect"
 	"strings"
 
 	"github.com/gohugoio/hugo/common/hreflect"
 	"github.com/gohugoio/hugo/common/maps"
 
-	"github.com/pkg/errors"
+	"errors"
 )
 
 // Merge creates a copy of the final parameter and merges the preceding
@@ -49,7 +50,7 @@ func (ns *Namespace) merge(src, dst any) (any, error) {
 	vdst, vsrc := reflect.ValueOf(dst), reflect.ValueOf(src)
 
 	if vdst.Kind() != reflect.Map {
-		return nil, errors.Errorf("destination must be a map, got %T", dst)
+		return nil, fmt.Errorf("destination must be a map, got %T", dst)
 	}
 
 	if !hreflect.IsTruthfulValue(vsrc) {
@@ -57,11 +58,11 @@ func (ns *Namespace) merge(src, dst any) (any, error) {
 	}
 
 	if vsrc.Kind() != reflect.Map {
-		return nil, errors.Errorf("source must be a map, got %T", src)
+		return nil, fmt.Errorf("source must be a map, got %T", src)
 	}
 
 	if vsrc.Type().Key() != vdst.Type().Key() {
-		return nil, errors.Errorf("incompatible map types, got %T to %T", src, dst)
+		return nil, fmt.Errorf("incompatible map types, got %T to %T", src, dst)
 	}
 
 	return mergeMap(vdst, vsrc).Interface(), nil

tpl/collections/reflect_helpers.go

@@ -18,8 +18,9 @@ import (
 	"reflect"
 	"time"
 
+	"errors"
+
 	"github.com/mitchellh/hashstructure"
-	"github.com/pkg/errors"
 )
 
 var (
@@ -103,7 +104,7 @@ func convertValue(v reflect.Value, to reflect.Type) (reflect.Value, error) {
 	case isNumber(kind):
 		return convertNumber(v, kind)
 	default:
-		return reflect.Value{}, errors.Errorf("%s is not assignable to %s", v.Type(), to)
+		return reflect.Value{}, fmt.Errorf("%s is not assignable to %s", v.Type(), to)
 	}
 }
 

tpl/collections/symdiff.go

@@ -16,8 +16,6 @@ package collections
 import (
 	"fmt"
 	"reflect"
-
-	"github.com/pkg/errors"
 )
 
 // SymDiff returns the symmetric difference of s1 and s2.
@@ -54,7 +52,7 @@ func (ns *Namespace) SymDiff(s2, s1 any) (any, error) {
 				if ids1[key] != ids2[key] {
 					v, err := convertValue(ev, sliceElemType)
 					if err != nil {
-						return nil, errors.WithMessage(err, "symdiff: failed to convert value")
+						return nil, fmt.Errorf("symdiff: failed to convert value: %w", err)
 					}
 					slice = reflect.Append(slice, v)
 				}