fine tune template error messages

modules/context/context.go

@@ -47,7 +47,7 @@ import (
 
 // Render represents a template render
 type Render interface {
-	TemplateLookup(tmpl string) *template.Template
+	TemplateLookup(tmpl string) (*template.Template, error)
 	HTML(w io.Writer, status int, name string, data interface{}) error
 }
 
@@ -228,7 +228,7 @@ func (ctx *Context) HTML(status int, name base.TplName) {
 	}
 	if err := ctx.Render.HTML(ctx.Resp, status, string(name), templates.BaseVars().Merge(ctx.Data)); err != nil {
 		if status == http.StatusInternalServerError && name == base.TplName("status/500") {
-			ctx.PlainText(http.StatusInternalServerError, "Unable to find status/500 template")
+			ctx.PlainText(http.StatusInternalServerError, "Unable to find HTML templates, the template system is not initialized, or Gitea can't find your template files")
 			return
 		}
 		if execErr, ok := err.(texttemplate.ExecError); ok {
@@ -247,7 +247,7 @@ func (ctx *Context) HTML(status int, name base.TplName) {
 				if errorTemplateName != string(name) {
 					filename += " (subtemplate of " + string(name) + ")"
 				}
-				err = fmt.Errorf("%w\nin template file %s:\n%s", err, filename, templates.GetLineFromTemplate(errorTemplateName, line, target, pos))
+				err = fmt.Errorf("failed to render %s, error: %w:\n%s", filename, err, templates.GetLineFromTemplate(errorTemplateName, line, target, pos))
 			} else {
 				filename, filenameErr := templates.GetAssetFilename("templates/" + execErr.Name + ".tmpl")
 				if filenameErr != nil {
@@ -256,7 +256,7 @@ func (ctx *Context) HTML(status int, name base.TplName) {
 				if execErr.Name != string(name) {
 					filename += " (subtemplate of " + string(name) + ")"
 				}
-				err = fmt.Errorf("%w\nin template file %s", err, filename)
+				err = fmt.Errorf("failed to render %s, error: %w", filename, err)
 			}
 		}
 		ctx.ServerError("Render failed", err)

modules/templates/htmlrenderer.go

@@ -6,6 +6,7 @@ package templates
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"html/template"
 	"io"
@@ -15,9 +16,11 @@ import (
 	"strconv"
 	"strings"
 	"sync/atomic"
+	texttemplate "text/template"
 
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/watcher"
 )
 
@@ -34,18 +37,32 @@ type HTMLRender struct {
 	templates atomic.Pointer[template.Template]
 }
 
+var ErrTemplateNotInitialized = errors.New("template system is not initialized, check your log for errors")
+
 func (h *HTMLRender) HTML(w io.Writer, status int, name string, data interface{}) error {
 	if respWriter, ok := w.(http.ResponseWriter); ok {
 		if respWriter.Header().Get("Content-Type") == "" {
 			respWriter.Header().Set("Content-Type", "text/html; charset=utf-8")
 		}
 		respWriter.WriteHeader(status)
 	}
-	return h.templates.Load().ExecuteTemplate(w, name, data)
+	t, err := h.TemplateLookup(name)
+	if err != nil {
+		return texttemplate.ExecError{Name: name, Err: err}
+	}
+	return t.Execute(w, data)
 }
 
-func (h *HTMLRender) TemplateLookup(t string) *template.Template {
-	return h.templates.Load().Lookup(t)
+func (h *HTMLRender) TemplateLookup(name string) (*template.Template, error) {
+	tmpls := h.templates.Load()
+	if tmpls == nil {
+		return nil, ErrTemplateNotInitialized
+	}
+	tmpl := tmpls.Lookup(name)
+	if tmpl == nil {
+		return nil, util.ErrNotExist
+	}
+	return tmpl, nil
 }
 
 func (h *HTMLRender) CompileTemplates() error {

routers/web/auth/oauth.go

@@ -578,12 +578,15 @@ func GrantApplicationOAuth(ctx *context.Context) {
 
 // OIDCWellKnown generates JSON so OIDC clients know Gitea's capabilities
 func OIDCWellKnown(ctx *context.Context) {
-	t := ctx.Render.TemplateLookup("user/auth/oidc_wellknown")
+	t, err := ctx.Render.TemplateLookup("user/auth/oidc_wellknown")
+	if err != nil {
+		ctx.ServerError("unable to find template", err)
+		return
+	}
 	ctx.Resp.Header().Set("Content-Type", "application/json")
 	ctx.Data["SigningKey"] = oauth2.DefaultSigningKey
-	if err := t.Execute(ctx.Resp, ctx.Data); err != nil {
-		log.Error("%v", err)
-		ctx.Error(http.StatusInternalServerError)
+	if err = t.Execute(ctx.Resp, ctx.Data); err != nil {
+		ctx.ServerError("unable to execute template", err)
 	}
 }
 

routers/web/swagger_json.go

@@ -4,22 +4,22 @@
 package web
 
 import (
-	"net/http"
-
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/context"
-	"code.gitea.io/gitea/modules/log"
 )
 
 // tplSwaggerV1Json swagger v1 json template
 const tplSwaggerV1Json base.TplName = "swagger/v1_json"
 
 // SwaggerV1Json render swagger v1 json
 func SwaggerV1Json(ctx *context.Context) {
-	t := ctx.Render.TemplateLookup(string(tplSwaggerV1Json))
+	t, err := ctx.Render.TemplateLookup(string(tplSwaggerV1Json))
+	if err != nil {
+		ctx.ServerError("unable to find template", err)
+		return
+	}
 	ctx.Resp.Header().Set("Content-Type", "application/json")
-	if err := t.Execute(ctx.Resp, ctx.Data); err != nil {
-		log.Error("%v", err)
-		ctx.Error(http.StatusInternalServerError)
+	if err = t.Execute(ctx.Resp, ctx.Data); err != nil {
+		ctx.ServerError("unable to execute template", err)
 	}
 }