resources: Replace error handling in GetRemote with try (note)

Closes #13216

common/herrors/file_error.go

@@ -258,16 +258,35 @@ func openFile(filename string, fs afero.Fs) (afero.File, string, error) {
 	return f, realFilename, nil
 }
 
-// Cause returns the underlying error or itself if it does not implement Unwrap.
+// Cause returns the underlying error, that is,
+// it unwraps errors until it finds one that does not implement
+// the Unwrap method.
+// For a shallow variant, see Unwrap.
 func Cause(err error) error {
+	type unwrapper interface {
+		Unwrap() error
+	}
+
+	for err != nil {
+		cause, ok := err.(unwrapper)
+		if !ok {
+			break
+		}
+		err = cause.Unwrap()
+	}
+	return err
+}
+
+// Unwrap returns the underlying error or itself if it does not implement Unwrap.
+func Unwrap(err error) error {
 	if u := errors.Unwrap(err); u != nil {
 		return u
 	}
 	return err
 }
 
 func extractFileTypePos(err error) (string, text.Position) {
-	err = Cause(err)
+	err = Unwrap(err)
 
 	var fileType string
 

hugolib/hugo_sites_build.go

@@ -343,6 +343,18 @@ func (h *HugoSites) render(l logg.LevelLogger, config *BuildCfg) error {
 
 	siteRenderContext := &siteRenderContext{cfg: config, multihost: h.Configs.IsMultihost}
 
+	renderErr := func(err error) error {
+		if err == nil {
+			return nil
+		}
+		if strings.Contains(err.Error(), "can't evaluate field Err in type resource.Resource") {
+			// In Hugo 0.141.0 we replaced the special error handling for resources.GetRemote
+			// with the more general try.
+			return fmt.Errorf("%s: Resource.Err was removed in Hugo v0.141.0 and replaced with a new try keyword, see https://gohugo.io/functions/go-template/try/", err)
+		}
+		return err
+	}
+
 	i := 0
 	for _, s := range h.Sites {
 		segmentFilter := s.conf.C.SegmentFilter
@@ -390,7 +402,7 @@ func (h *HugoSites) render(l logg.LevelLogger, config *BuildCfg) error {
 							}
 						} else {
 							if err := s.render(siteRenderContext); err != nil {
-								return err
+								return renderErr(err)
 							}
 						}
 						loggers.TimeTrackf(ll, start, nil, "")

hugolib/page.go

@@ -185,10 +185,6 @@ func (p *pageState) isContentNodeBranch() bool {
 	return p.IsNode()
 }
 
-func (p *pageState) Err() resource.ResourceError {
-	return nil
-}
-
 // Eq returns whether the current page equals the given page.
 // This is what's invoked when doing `{{ if eq $page $otherPage }}`
 func (p *pageState) Eq(other any) bool {

hugolib/resource_chain_test.go

@@ -67,22 +67,22 @@ FIT: {{ $fit.Name }}|{{ $fit.RelPermalink }}|{{ $fit.Width }}
 CSS integrity Data first: {{ $cssFingerprinted1.Data.Integrity }} {{ $cssFingerprinted1.RelPermalink }}
 CSS integrity Data last:  {{ $cssFingerprinted2.RelPermalink }} {{ $cssFingerprinted2.Data.Integrity }}
 
-{{ $failedImg := resources.GetRemote "%[1]s/fail.jpg" }}
+{{ $failedImg := try (resources.GetRemote "%[1]s/fail.jpg") }}
 {{ $rimg := resources.GetRemote "%[1]s/sunset.jpg" }}
 {{ $remotenotfound := resources.GetRemote "%[1]s/notfound.jpg" }}
 {{ $localnotfound := resources.Get "images/notfound.jpg" }}
-{{ $gopherprotocol := resources.GetRemote "gopher://example.org" }}
+{{ $gopherprotocol := try (resources.GetRemote "gopher://example.org") }}
 {{ $rfit := $rimg.Fit "200x200" }}
 {{ $rfit2 := $rfit.Fit "100x200" }}
 {{ $rimg = $rimg | fingerprint }}
 SUNSET REMOTE: {{ $rimg.Name }}|{{ $rimg.RelPermalink }}|{{ $rimg.Width }}|{{ len $rimg.Content }}
 FIT REMOTE: {{ $rfit.Name }}|{{ $rfit.RelPermalink }}|{{ $rfit.Width }}
 REMOTE NOT FOUND: {{ if $remotenotfound }}FAILED{{ else}}OK{{ end }}
 LOCAL NOT FOUND: {{ if $localnotfound }}FAILED{{ else}}OK{{ end }}
-PRINT PROTOCOL ERROR1: {{ with $gopherprotocol }}{{ . | safeHTML }}{{ end }}
+PRINT PROTOCOL ERROR1: {{ with $gopherprotocol }}{{ .Value | safeHTML }}{{ end }}
 PRINT PROTOCOL ERROR2: {{ with $gopherprotocol }}{{ .Err | safeHTML }}{{ end }}
-PRINT PROTOCOL ERROR DETAILS: {{ with $gopherprotocol }}Err: {{ .Err | safeHTML }}{{ with .Err }}|{{ with .Data }}Body: {{ .Body }}|StatusCode: {{ .StatusCode }}{{ end }}|{{ end }}{{ end }}
-FAILED REMOTE ERROR DETAILS CONTENT: {{ with $failedImg.Err }}|{{ . }}|{{ with .Data }}Body: {{ .Body }}|StatusCode: {{ .StatusCode }}|ContentLength: {{ .ContentLength }}|ContentType: {{ .ContentType }}{{ end }}{{ end }}|
+PRINT PROTOCOL ERROR DETAILS: {{ with $gopherprotocol }}{{ with .Err }}Err: {{ . | safeHTML }}{{ with .Cause }}|{{ with .Data }}Body: {{ .Body }}|StatusCode: {{ .StatusCode }}{{ end }}|{{ end }}{{ end }}{{ end }}
+FAILED REMOTE ERROR DETAILS CONTENT: {{ with $failedImg }}{{ with .Err }}{{ with .Cause }}{{ . }}|{{ with .Data }}Body: {{ .Body }}|StatusCode: {{ .StatusCode }}|ContentLength: {{ .ContentLength }}|ContentType: {{ .ContentType }}{{ end }}{{ end }}{{ end }}{{ end }}|
 `, ts.URL))
 
 	fs := b.Fs.Source
@@ -114,8 +114,8 @@ SUNSET REMOTE: /sunset_%[1]s.jpg|/sunset_%[1]s.a9bf1d944e19c0f382e0d8f51de690f7d
 FIT REMOTE: /sunset_%[1]s.jpg|/sunset_%[1]s_hu15210517121918042184.jpg|200
 REMOTE NOT FOUND: OK
 LOCAL NOT FOUND: OK
-PRINT PROTOCOL ERROR DETAILS: Err: error calling resources.GetRemote: Get "gopher://example.org": unsupported protocol scheme "gopher"||
-FAILED REMOTE ERROR DETAILS CONTENT: |failed to fetch remote resource from '%[2]s/fail.jpg': Not Implemented|Body: { msg: failed }
+PRINT PROTOCOL ERROR DETAILS: Err: template: index.html:22:36: executing "index.html" at <resources.GetRemote>: error calling GetRemote: Get "gopher://example.org": unsupported protocol scheme "gopher"|
+FAILED REMOTE ERROR DETAILS CONTENT: failed to fetch remote resource from &#39;%[2]s/fail.jpg&#39;: Not Implemented|Body: { msg: failed }
 |StatusCode: 501|ContentLength: 16|ContentType: text/plain; charset=utf-8|
 
 

resources/page/page_nop.go

@@ -61,10 +61,6 @@ type nopPage int
 
 var noOpPathInfo = media.DefaultPathParser.Parse(files.ComponentFolderContent, "no-op.md")
 
-func (p *nopPage) Err() resource.ResourceError {
-	return nil
-}
-
 func (p *nopPage) Aliases() []string {
 	return nil
 }

resources/page/testhelpers_test.go

@@ -111,10 +111,6 @@ type testPage struct {
 	sectionEntries []string
 }
 
-func (p *testPage) Err() resource.ResourceError {
-	return nil
-}
-
 func (p *testPage) Aliases() []string {
 	panic("testpage: not implemented")
 }

resources/resource.go

@@ -224,9 +224,6 @@ type resourceCopier interface {
 
 // Copy copies r to the targetPath given.
 func Copy(r resource.Resource, targetPath string) resource.Resource {
-	if r.Err() != nil {
-		panic(fmt.Sprintf("Resource has an .Err: %s", r.Err()))
-	}
 	return r.(resourceCopier).cloneTo(targetPath)
 }
 
@@ -439,10 +436,6 @@ func (l *genericResource) Content(context.Context) (any, error) {
 	return hugio.ReadString(r)
 }
 
-func (r *genericResource) Err() resource.ResourceError {
-	return nil
-}
-
 func (l *genericResource) Data() any {
 	return l.sd.Data
 }

resources/resource/resourcetypes.go

@@ -43,6 +43,9 @@ type OriginProvider interface {
 
 // NewResourceError creates a new ResourceError.
 func NewResourceError(err error, data any) ResourceError {
+	if data == nil {
+		data = map[string]any{}
+	}
 	return &resourceError{
 		error: err,
 		data:  data,
@@ -65,13 +68,6 @@ type ResourceError interface {
 	ResourceDataProvider
 }
 
-// ErrProvider provides an Err.
-type ErrProvider interface {
-	// Err returns an error if this resource is in an error state.
-	// This will currently only be set for resources obtained from resources.GetRemote.
-	Err() ResourceError
-}
-
 // Resource represents a linkable resource, i.e. a content page, image etc.
 type Resource interface {
 	ResourceWithoutMeta
@@ -83,7 +79,6 @@ type ResourceWithoutMeta interface {
 	MediaTypeProvider
 	ResourceLinksProvider
 	ResourceDataProvider
-	ErrProvider
 }
 
 type ResourceWrapper interface {

resources/resource_factories/create/create_integration_test.go

@@ -31,18 +31,17 @@ func TestGetRemoteHead(t *testing.T) {
   [security.http]
     methods = ['(?i)GET|POST|HEAD']
     urls = ['.*gohugo\.io.*']
-
 -- layouts/index.html --
 {{ $url := "https://gohugo.io/img/hugo.png" }}
 {{ $opts := dict "method" "head" }}
-{{ with resources.GetRemote $url $opts }}
+{{ with try (resources.GetRemote $url $opts) }}
   {{ with .Err }}
     {{ errorf "Unable to get remote resource: %s" . }}
-  {{ else }}
+  {{ else with .Value }}
     Head Content: {{ .Content }}. Head Data: {{ .Data }}
-  {{ end }}
-{{ else }}
+  {{ else }}
   {{ errorf "Unable to get remote resource: %s" $url }}
+  {{ end }}
 {{ end }}
 `
 
@@ -90,14 +89,15 @@ mediaTypes = ['text/plain']
 -- layouts/_default/single.html --
 {{ $url := printf "%s%s" "URL" .RelPermalink}}
 {{ $opts := dict }}
-{{ with resources.GetRemote $url $opts }}
+{{ with try (resources.GetRemote $url $opts) }}
   {{ with .Err }}
-    {{ errorf "Got Err: %s. Data: %v" . .Data }}
-  {{ else }}
+     {{ errorf "Got Err: %s" . }}
+	 {{ with .Cause }}{{ errorf "Data: %s" .Data }}{{ end }}
+  {{ else with .Value }}
     Content: {{ .Content }}
+  {{ else }}
+    {{ errorf "Unable to get remote resource: %s" $url }}
   {{ end }}
-{{ else }}
-  {{ errorf "Unable to get remote resource: %s" $url }}
 {{ end }}
 `
 

resources/transform.go

@@ -192,10 +192,6 @@ func (r *resourceAdapter) Content(ctx context.Context) (any, error) {
 	return r.target.Content(ctx)
 }
 
-func (r *resourceAdapter) Err() resource.ResourceError {
-	return nil
-}
-
 func (r *resourceAdapter) GetIdentity() identity.Identity {
 	return identity.FirstIdentity(r.target)
 }