errors: Misc improvements

* Redo the server error template
* Always add the content file context if relevant
* Remove some now superflous error string matching
* Move the server error template to _server/error.html
* Add file context (with position) to codeblock render blocks
* Improve JS build errors

Fixes #9892
Fixes #9891
Fixes #9893

tpl/tplimpl/template.go

@@ -61,6 +61,7 @@ const (
 
 // The identifiers may be truncated in the log, e.g.
 // "executing "main" at <$scaled.SRelPermalin...>: can't evaluate field SRelPermalink in type *resource.Image"
+// We need this to identify position in templates with base templates applied.
 var identifiersRe = regexp.MustCompile(`at \<(.*?)(\.{3})?\>:`)
 
 var embeddedTemplatesAliases = map[string][]string{
@@ -524,25 +525,27 @@ func (t *templateHandler) addFileContext(templ tpl.Template, inerr error) error
 		return inerr
 	}
 
+	identifiers := t.extractIdentifiers(inerr.Error())
+
 	//lint:ignore ST1008 the error is the main result
 	checkFilename := func(info templateInfo, inErr error) (error, bool) {
 		if info.filename == "" {
 			return inErr, false
 		}
 
-		lineMatcher := func(m herrors.LineMatcher) bool {
+		lineMatcher := func(m herrors.LineMatcher) int {
 			if m.Position.LineNumber != m.LineNumber {
-				return false
+				return -1
 			}
 
-			identifiers := t.extractIdentifiers(m.Error.Error())
-
 			for _, id := range identifiers {
 				if strings.Contains(m.Line, id) {
-					return true
+					// We found the line, but return a 0 to signal to
+					// use the column from the error message.
+					return 0
 				}
 			}
-			return false
+			return -1
 		}
 
 		f, err := t.layoutsFs.Open(info.filename)
@@ -551,7 +554,13 @@ func (t *templateHandler) addFileContext(templ tpl.Template, inerr error) error
 		}
 		defer f.Close()
 
-		return herrors.NewFileError(info.realFilename, inErr).UpdateContent(f, lineMatcher), true
+		fe := herrors.NewFileError(info.realFilename, inErr)
+		fe.UpdateContent(f, lineMatcher)
+
+		if !fe.ErrorContext().Position.IsValid() {
+			return inErr, false
+		}
+		return fe, true
 	}
 
 	inerr = fmt.Errorf("execute of template failed: %w", inerr)
@@ -565,6 +574,15 @@ func (t *templateHandler) addFileContext(templ tpl.Template, inerr error) error
 	return err
 }
 
+func (t *templateHandler) extractIdentifiers(line string) []string {
+	m := identifiersRe.FindAllStringSubmatch(line, -1)
+	identifiers := make([]string, len(m))
+	for i := 0; i < len(m); i++ {
+		identifiers[i] = m[i][1]
+	}
+	return identifiers
+}
+
 func (t *templateHandler) addShortcodeVariant(ts *templateState) {
 	name := ts.Name()
 	base := templateBaseName(templateShortcode, name)
@@ -721,18 +739,9 @@ func (t *templateHandler) applyTemplateTransformers(ns *templateNamespace, ts *t
 	return c, err
 }
 
-func (t *templateHandler) extractIdentifiers(line string) []string {
-	m := identifiersRe.FindAllStringSubmatch(line, -1)
-	identifiers := make([]string, len(m))
-	for i := 0; i < len(m); i++ {
-		identifiers[i] = m[i][1]
-	}
-	return identifiers
-}
-
 //go:embed embedded/templates/*
 //go:embed embedded/templates/_default/*
-//go:embed embedded/templates/server/*
+//go:embed embedded/templates/_server/*
 var embededTemplatesFs embed.FS
 
 func (t *templateHandler) loadEmbedded() error {
@@ -755,7 +764,7 @@ func (t *templateHandler) loadEmbedded() error {
 		// For the render hooks and the server templates it does not make sense to preseve the
 		// double _indternal double book-keeping,
 		// just add it if its now provided by the user.
-		if !strings.Contains(path, "_default/_markup") && !strings.HasPrefix(name, "server/") {
+		if !strings.Contains(path, "_default/_markup") && !strings.HasPrefix(name, "_server/") {
 			templateName = internalPathPrefix + name
 		}