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 pkg/errors#223 -- but also because most of this is now built-in to Go.

Fixes gohugoio#9852
Fixes gohugoio#9857
Fixes gohugoio#9863

Author: bep

cache/filecache/filecache_config.go

@@ -14,6 +14,7 @@
 package filecache
 
 import (
+	"fmt"
 	"path"
 	"path/filepath"
 	"strings"
@@ -25,8 +26,9 @@ import (
 
 	"github.com/gohugoio/hugo/helpers"
 
+	"errors"
+
 	"github.com/mitchellh/mapstructure"
-	"github.com/pkg/errors"
 	"github.com/spf13/afero"
 )
 
@@ -153,7 +155,7 @@ func DecodeConfig(fs afero.Fs, cfg config.Provider) (Configs, error) {
 		}
 
 		if err := decoder.Decode(v); err != nil {
-			return nil, errors.Wrap(err, "failed to decode filecache config")
+			return nil, fmt.Errorf("failed to decode filecache config: %w", err)
 		}
 
 		if cc.Dir == "" {
@@ -162,7 +164,7 @@ func DecodeConfig(fs afero.Fs, cfg config.Provider) (Configs, error) {
 
 		name := strings.ToLower(k)
 		if !valid[name] {
-			return nil, errors.Errorf("%q is not a valid cache name", name)
+			return nil, fmt.Errorf("%q is not a valid cache name", name)
 		}
 
 		c[name] = cc
@@ -197,12 +199,12 @@ func DecodeConfig(fs afero.Fs, cfg config.Provider) (Configs, error) {
 
 		if !v.isResourceDir {
 			if isOsFs && !filepath.IsAbs(v.Dir) {
-				return c, errors.Errorf("%q must resolve to an absolute directory", v.Dir)
+				return c, fmt.Errorf("%q must resolve to an absolute directory", v.Dir)
 			}
 
 			// Avoid cache in root, e.g. / (Unix) or c:\ (Windows)
 			if len(strings.TrimPrefix(v.Dir, filepath.VolumeName(v.Dir))) == 1 {
-				return c, errors.Errorf("%q is a root folder and not allowed as cache dir", v.Dir)
+				return c, fmt.Errorf("%q is a root folder and not allowed as cache dir", v.Dir)
 			}
 		}
 
@@ -242,5 +244,5 @@ func resolveDirPlaceholder(fs afero.Fs, cfg config.Provider, placeholder string)
 		return filepath.Base(workingDir), false, nil
 	}
 
-	return "", false, errors.Errorf("%q is not a valid placeholder (valid values are :cacheDir or :resourceDir)", placeholder)
+	return "", false, fmt.Errorf("%q is not a valid placeholder (valid values are :cacheDir or :resourceDir)", placeholder)
 }

cache/filecache/filecache_pruner.go

@@ -14,12 +14,12 @@
 package filecache
 
 import (
+	"fmt"
 	"io"
 	"os"
 
 	"github.com/gohugoio/hugo/hugofs"
 
-	"github.com/pkg/errors"
 	"github.com/spf13/afero"
 )
 
@@ -39,7 +39,7 @@ func (c Caches) Prune() (int, error) {
 			if os.IsNotExist(err) {
 				continue
 			}
-			return counter, errors.Wrapf(err, "failed to prune cache %q", k)
+			return counter, fmt.Errorf("failed to prune cache %q: %w", k, err)
 		}
 
 	}

commands/commandeer.go

@@ -14,7 +14,6 @@
 package commands
 
 import (
-	"bytes"
 	"errors"
 	"io/ioutil"
 	"net"
@@ -141,19 +140,11 @@ func (c *commandeer) getErrorWithContext() any {
 
 	m := make(map[string]any)
 
-	m["Error"] = errors.New(removeErrorPrefixFromLog(c.logger.Errors()))
+	//xwm["Error"] = errors.New(cleanErrorLog(removeErrorPrefixFromLog(c.logger.Errors())))
+	m["Error"] = errors.New(cleanErrorLog(removeErrorPrefixFromLog(c.logger.Errors())))
 	m["Version"] = hugo.BuildVersionString()
-
-	fe := herrors.UnwrapErrorWithFileContext(c.buildErr)
-	if fe != nil {
-		m["File"] = fe
-	}
-
-	if c.h.verbose {
-		var b bytes.Buffer
-		herrors.FprintStackTraceFromErr(&b, c.buildErr)
-		m["StackTrace"] = b.String()
-	}
+	ferrors := herrors.UnwrapFileErrorsWithErrorContext(c.buildErr)
+	m["Files"] = ferrors
 
 	return m
 }

commands/convert.go

@@ -31,8 +31,6 @@ import (
 	"github.com/gohugoio/hugo/parser"
 	"github.com/gohugoio/hugo/parser/metadecoders"
 
-	"github.com/pkg/errors"
-
 	"github.com/gohugoio/hugo/hugolib"
 
 	"github.com/spf13/cobra"
@@ -193,7 +191,7 @@ func (cc *convertCmd) convertAndSavePage(p page.Page, site *hugolib.Site, target
 
 	fs := hugofs.Os
 	if err := helpers.WriteToDisk(newFilename, &newContent, fs); err != nil {
-		return errors.Wrapf(err, "Failed to save file %q:", newFilename)
+		return fmt.Errorf("Failed to save file %q:: %w", newFilename, err)
 	}
 
 	return nil

commands/hugo.go

@@ -39,9 +39,6 @@ import (
 
 	"github.com/gohugoio/hugo/resources/page"
 
-	"github.com/pkg/errors"
-
-	"github.com/gohugoio/hugo/common/herrors"
 	"github.com/gohugoio/hugo/common/hugo"
 	"github.com/gohugoio/hugo/common/loggers"
 	"github.com/gohugoio/hugo/common/terminal"
@@ -300,14 +297,14 @@ func (c *commandeer) fullBuild(noBuildLock bool) error {
 	copyStaticFunc := func() error {
 		cnt, err := c.copyStatic()
 		if err != nil {
-			return errors.Wrap(err, "Error copying static files")
+			return fmt.Errorf("Error copying static files: %w", err)
 		}
 		langCount = cnt
 		return nil
 	}
 	buildSitesFunc := func() error {
 		if err := c.buildSites(noBuildLock); err != nil {
-			return errors.Wrap(err, "Error building site")
+			return fmt.Errorf("Error building site: %w", err)
 		}
 		return nil
 	}
@@ -354,10 +351,10 @@ func (c *commandeer) initCPUProfile() (func(), error) {
 
 	f, err := os.Create(c.h.cpuprofile)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to create CPU profile")
+		return nil, fmt.Errorf("failed to create CPU profile: %w", err)
 	}
 	if err := pprof.StartCPUProfile(f); err != nil {
-		return nil, errors.Wrap(err, "failed to start CPU profile")
+		return nil, fmt.Errorf("failed to start CPU profile: %w", err)
 	}
 	return func() {
 		pprof.StopCPUProfile()
@@ -388,11 +385,11 @@ func (c *commandeer) initTraceProfile() (func(), error) {
 
 	f, err := os.Create(c.h.traceprofile)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to create trace file")
+		return nil, fmt.Errorf("failed to create trace file: %w", err)
 	}
 
 	if err := trace.Start(f); err != nil {
-		return nil, errors.Wrap(err, "failed to start trace")
+		return nil, fmt.Errorf("failed to start trace: %w", err)
 	}
 
 	return func() {
@@ -735,9 +732,7 @@ func (c *commandeer) handleBuildErr(err error, msg string) {
 
 	c.logger.Errorln(msg + ":\n")
 	c.logger.Errorln(helpers.FirstUpper(err.Error()))
-	if !c.h.quiet && c.h.verbose {
-		herrors.PrintStackTraceFromErr(err)
-	}
+
 }
 
 func (c *commandeer) rebuildSites(events []fsnotify.Event) error {

commands/new_site.go

@@ -16,14 +16,13 @@ package commands
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"path/filepath"
 	"strings"
 
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/parser/metadecoders"
 
-	_errors "github.com/pkg/errors"
-
 	"github.com/gohugoio/hugo/create"
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/hugofs"
@@ -94,7 +93,7 @@ func (n *newSiteCmd) doNewSite(fs *hugofs.Fs, basepath string, force bool) error
 
 	for _, dir := range dirs {
 		if err := fs.Source.MkdirAll(dir, 0777); err != nil {
-			return _errors.Wrap(err, "Failed to create dir")
+			return fmt.Errorf("Failed to create dir: %w", err)
 		}
 	}
 

commands/server.go

@@ -36,8 +36,6 @@ import (
 	"github.com/gohugoio/hugo/common/paths"
 	"golang.org/x/sync/errgroup"
 
-	"github.com/pkg/errors"
-
 	"github.com/gohugoio/hugo/livereload"
 
 	"github.com/gohugoio/hugo/config"
@@ -366,7 +364,7 @@ func (f *fileServer) createEndpoint(i int) (*http.ServeMux, net.Listener, string
 	// We're only interested in the path
 	u, err := url.Parse(baseURL)
 	if err != nil {
-		return nil, nil, "", "", errors.Wrap(err, "Invalid baseURL")
+		return nil, nil, "", "", fmt.Errorf("Invalid baseURL: %w", err)
 	}
 
 	decorate := func(h http.Handler) http.Handler {
@@ -480,6 +478,21 @@ var logErrorRe = regexp.MustCompile(`(?s)ERROR \d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{
 func removeErrorPrefixFromLog(content string) string {
 	return logErrorRe.ReplaceAllLiteralString(content, "")
 }
+func cleanErrorLog(content string) string {
+	content = strings.ReplaceAll(content, "Rebuild failed:\n", "")
+	content = strings.ReplaceAll(content, "\n", "")
+	seen := make(map[string]bool)
+	parts := strings.Split(content, ": ")
+	keep := make([]string, 0, len(parts))
+	for _, part := range parts {
+		if seen[part] {
+			continue
+		}
+		seen[part] = true
+		keep = append(keep, part)
+	}
+	return strings.Join(keep, ": ")
+}
 
 func (c *commandeer) serve(s *serverCmd) error {
 	isMultiHost := c.hugo().IsMultihost()
@@ -500,17 +513,16 @@ func (c *commandeer) serve(s *serverCmd) error {
 		roots = []string{""}
 	}
 
-	templ, err := c.hugo().TextTmpl().Parse("__default_server_error", buildErrorTemplate)
-	if err != nil {
-		return err
-	}
-
 	srv := &fileServer{
 		baseURLs: baseURLs,
 		roots:    roots,
 		c:        c,
 		s:        s,
 		errorTemplate: func(ctx any) (io.Reader, error) {
+			templ, found := c.hugo().Tmpl().Lookup("server/error.html")
+			if !found {
+				panic("template server/error.html not found")
+			}
 			b := &bytes.Buffer{}
 			err := c.hugo().Tmpl().Execute(templ, b, ctx)
 			return b, err
@@ -627,7 +639,7 @@ func (sc *serverCmd) fixURL(cfg config.Provider, s string, port int) (string, er
 		if strings.Contains(u.Host, ":") {
 			u.Host, _, err = net.SplitHostPort(u.Host)
 			if err != nil {
-				return "", errors.Wrap(err, "Failed to split baseURL hostpost")
+				return "", fmt.Errorf("Failed to split baseURL hostpost: %w", err)
 			}
 		}
 		u.Host += fmt.Sprintf(":%d", port)

commands/server_errors.go

@@ -22,67 +22,6 @@ import (
 	"github.com/gohugoio/hugo/transform/livereloadinject"
 )
 
-var buildErrorTemplate = `<!doctype html>
-<html class="no-js" lang="">
-	<head>
-		<meta charset="utf-8">
-		<title>Hugo Server: Error</title>
-		<style type="text/css">
-		body {
-			font-family: "Muli",avenir, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
-			font-size: 16px;
-			background-color: #2f1e2e;
-		}
-		main {
-			margin: auto;
-			width: 95%;
-			padding: 1rem;
-		}		
-		.version {
-			color: #ccc;
-			padding: 1rem 0;
-		}
-		.stack {
-			margin-top: 4rem;
-		}
-		pre {
-			white-space: pre-wrap;      
-			white-space: -moz-pre-wrap;  
-			white-space: -pre-wrap;     
-			white-space: -o-pre-wrap;    
-			word-wrap: break-word;     
-		}
-		.highlight {
-			overflow-x: auto;
-			margin-bottom: 1rem;
-		}
-		a {
-			color: #0594cb;
-			text-decoration: none;
-		}
-		a:hover {
-			color: #ccc;
-		}
-		</style>
-	</head>
-	<body>
-		<main>
-			{{ highlight .Error "apl" "linenos=false,noclasses=true,style=paraiso-dark" }}
-			{{ with .File }}
-			{{ $params := printf "noclasses=true,style=paraiso-dark,linenos=table,hl_lines=%d,linenostart=%d" (add .LinesPos 1) (sub .Position.LineNumber .LinesPos) }}
-			{{ $lexer := .ChromaLexer | default "go-html-template" }}
-			{{  highlight (delimit .Lines "\n") $lexer $params }}
-			{{ end }}
-			{{ with .StackTrace }}
-			{{ highlight . "apl" "noclasses=true,style=paraiso-dark" }}
-			{{ end }}
-			<p class="version">{{ .Version }}</p>
-			<a href="">Reload Page</a>
-		</main>
-</body>
-</html>
-`
-
 func injectLiveReloadScript(src io.Reader, baseURL url.URL) string {
 	var b bytes.Buffer
 	chain := transform.Chain{livereloadinject.New(baseURL)}