Improve SASS errors

Fixes #9897

9 files changed, 179 insertions, 53 deletions

diff --git a/resources/resource_transformers/js/build.go b/resources/resource_transformers/js/build.go
index 34dae4666..23e28f675 100644
--- a/resources/resource_transformers/js/build.go
+++ b/resources/resource_transformers/js/build.go
@@ -165,7 +165,7 @@ func (t *buildTransformation) Transform(ctx *resources.ResourceTransformationCtx
 
 			if err == nil {
 				fe := herrors.
-					NewFileError(errors.New(errorMessage), path).
+					NewFileErrorFromName(errors.New(errorMessage), path).
 					UpdatePosition(text.Position{Offset: -1, LineNumber: loc.Line, ColumnNumber: loc.Column}).
 					UpdateContent(f, nil)
 
diff --git a/resources/resource_transformers/postcss/integration_test.go b/resources/resource_transformers/postcss/integration_test.go
index 69f0964d0..fdebcc52c 100644
--- a/resources/resource_transformers/postcss/integration_test.go
+++ b/resources/resource_transformers/postcss/integration_test.go
@@ -183,6 +183,6 @@ func TestTransformPostCSSImporSkipInlineImportsNotFound(t *testing.T) {
 			TxtarString:     files,
 		}).Build()
 
-	s.AssertFileContent("public/css/styles.css", filepath.FromSlash(`@import "components/doesnotexist.css";`))
+	s.AssertFileContent("public/css/styles.css", `@import "components/doesnotexist.css";`)
 
 }
diff --git a/resources/resource_transformers/postcss/postcss.go b/resources/resource_transformers/postcss/postcss.go
index 325dc1ec2..ed08f7202 100644
--- a/resources/resource_transformers/postcss/postcss.go
+++ b/resources/resource_transformers/postcss/postcss.go
@@ -314,7 +314,7 @@ func (imp *importResolver) importRecursive(
 					LineNumber:   offset + 1,
 					ColumnNumber: column + 1,
 				}
-				return 0, "", herrors.NewFileErrorFromFileInPos(fmt.Errorf("failed to resolve CSS @import %q", filename), pos, imp.fs, nil)
+				return 0, "", herrors.NewFileErrorFromFileInPos(fmt.Errorf("failed to resolve CSS @import \"%s\"", filename), pos, imp.fs, nil)
 			}
 
 			i--
@@ -421,7 +421,7 @@ func (imp *importResolver) toFileError(output string) error {
 	}
 	defer f.Close()
 
-	ferr := herrors.NewFileError(inErr, realFilename)
+	ferr := herrors.NewFileErrorFromName(inErr, realFilename)
 	pos := ferr.Position()
 	pos.LineNumber = file.Offset + 1
 	return ferr.UpdatePosition(pos).UpdateContent(f, nil)
diff --git a/resources/resource_transformers/tocss/dartsass/client.go b/resources/resource_transformers/tocss/dartsass/client.go
index fb794f4e8..7c3a7ecba 100644
--- a/resources/resource_transformers/tocss/dartsass/client.go
+++ b/resources/resource_transformers/tocss/dartsass/client.go
@@ -20,7 +20,9 @@ import (
 	"io"
 	"strings"
 
+	"github.com/gohugoio/hugo/common/herrors"
 	"github.com/gohugoio/hugo/helpers"
+	"github.com/gohugoio/hugo/hugofs"
 	"github.com/gohugoio/hugo/hugolib/filesystems"
 	"github.com/gohugoio/hugo/resources"
 	"github.com/gohugoio/hugo/resources/resource"
@@ -33,6 +35,10 @@ import (
 // used as part of the cache key.
 const transformationName = "tocss-dart"
 
+// See https://github.com/sass/dart-sass-embedded/issues/24
+// Note: This prefix must be all lower case.
+const dartSassStdinPrefix = "hugostdin:"
+
 func New(fs *filesystems.SourceFilesystem, rs *resources.Spec) (*Client, error) {
 	if !Supports() {
 		return &Client{dartSassNotAvailable: true}, nil
@@ -44,7 +50,7 @@ func New(fs *filesystems.SourceFilesystem, rs *resources.Spec) (*Client, error)
 
 	transpiler, err := godartsass.Start(godartsass.Options{
 		LogEventHandler: func(event godartsass.LogEvent) {
-			message := strings.ReplaceAll(event.Message, stdinPrefix, "")
+			message := strings.ReplaceAll(event.Message, dartSassStdinPrefix, "")
 			switch event.Type {
 			case godartsass.LogEventTypeDebug:
 				// Log as Info for now, we may adjust this if it gets too chatty.
@@ -94,7 +100,7 @@ func (c *Client) toCSS(args godartsass.Args, src io.Reader) (godartsass.Result,
 		if err.Error() == "unexpected EOF" {
 			return res, fmt.Errorf("got unexpected EOF when executing %q. The user running hugo must have read and execute permissions on this program. With execute permissions only, this error is thrown.", dartSassEmbeddedBinaryName)
 		}
-		return res, err
+		return res, herrors.NewFileErrorFromFileInErr(err, hugofs.Os, herrors.OffsetMatcher)
 	}
 
 	return res, err
diff --git a/resources/resource_transformers/tocss/dartsass/integration_test.go b/resources/resource_transformers/tocss/dartsass/integration_test.go
index a1ac1d59f..c127057a5 100644
--- a/resources/resource_transformers/tocss/dartsass/integration_test.go
+++ b/resources/resource_transformers/tocss/dartsass/integration_test.go
@@ -14,8 +14,10 @@
 package dartsass_test
 
 import (
+	"strings"
 	"testing"
 
+	qt "github.com/frankban/quicktest"
 	"github.com/gohugoio/hugo/hugolib"
 	"github.com/gohugoio/hugo/resources/resource_transformers/tocss/dartsass"
 	jww "github.com/spf13/jwalterweatherman"
@@ -196,3 +198,76 @@ T1: {{ $r.Content }}
 	b.AssertLogMatches(`INFO.*Dart Sass: .*assets.*main.scss:1:0: bar`)
 
 }
+
+func TestTransformErrors(t *testing.T) {
+	if !dartsass.Supports() {
+		t.Skip()
+	}
+
+	c := qt.New(t)
+
+	const filesTemplate = `
+-- config.toml --
+-- assets/scss/components/_foo.scss --
+/* comment line 1 */
+$foocolor: #ccc;
+
+foo {
+	color: $foocolor;
+}
+-- assets/scss/main.scss --
+/* comment line 1 */
+/* comment line 2 */
+@import "components/foo";
+/* comment line 4 */
+
+  $maincolor: #eee;
+
+body {
+	color: $maincolor;
+}
+
+-- layouts/index.html --
+{{ $cssOpts := dict "transpiler" "dartsass" }}
+{{ $r := resources.Get "scss/main.scss" |  toCSS $cssOpts  | minify  }}
+T1: {{ $r.Content }}
+
+	`
+
+	c.Run("error in main", func(c *qt.C) {
+		b, err := hugolib.NewIntegrationTestBuilder(
+			hugolib.IntegrationTestConfig{
+				T:           c,
+				TxtarString: strings.Replace(filesTemplate, "$maincolor: #eee;", "$maincolor #eee;", 1),
+				NeedsOsFS:   true,
+			}).BuildE()
+
+		b.Assert(err, qt.IsNotNil)
+		b.Assert(err.Error(), qt.Contains, `main.scss:8:13":`)
+		b.Assert(err.Error(), qt.Contains, `: expected ":".`)
+		fe := b.AssertIsFileError(err)
+		b.Assert(fe.ErrorContext(), qt.IsNotNil)
+		b.Assert(fe.ErrorContext().Lines, qt.DeepEquals, []string{"  $maincolor #eee;", "", "body {", "\tcolor: $maincolor;", "}"})
+		b.Assert(fe.ErrorContext().ChromaLexer, qt.Equals, "scss")
+
+	})
+
+	c.Run("error in import", func(c *qt.C) {
+		b, err := hugolib.NewIntegrationTestBuilder(
+			hugolib.IntegrationTestConfig{
+				T:           c,
+				TxtarString: strings.Replace(filesTemplate, "$foocolor: #ccc;", "$foocolor #ccc;", 1),
+				NeedsOsFS:   true,
+			}).BuildE()
+
+		b.Assert(err, qt.IsNotNil)
+		b.Assert(err.Error(), qt.Contains, `_foo.scss:2:10":`)
+		b.Assert(err.Error(), qt.Contains, `: expected ":".`)
+		fe := b.AssertIsFileError(err)
+		b.Assert(fe.ErrorContext(), qt.IsNotNil)
+		b.Assert(fe.ErrorContext().Lines, qt.DeepEquals, []string{"/* comment line 1 */", "$foocolor #ccc;", "", "foo {"})
+		b.Assert(fe.ErrorContext().ChromaLexer, qt.Equals, "scss")
+
+	})
+
+}
diff --git a/resources/resource_transformers/tocss/dartsass/transform.go b/resources/resource_transformers/tocss/dartsass/transform.go
index ba3517e26..9d17d3bcc 100644
--- a/resources/resource_transformers/tocss/dartsass/transform.go
+++ b/resources/resource_transformers/tocss/dartsass/transform.go
@@ -16,13 +16,12 @@ package dartsass
 import (
 	"fmt"
 	"io"
-	"net/url"
 	"path"
 	"path/filepath"
 	"strings"
 
-	"github.com/gohugoio/hugo/common/herrors"
 	"github.com/gohugoio/hugo/common/hexec"
+	"github.com/gohugoio/hugo/common/paths"
 	"github.com/gohugoio/hugo/htesting"
 	"github.com/gohugoio/hugo/media"
 
@@ -38,9 +37,6 @@ import (
 )
 
 const (
-	// See https://github.com/sass/dart-sass-embedded/issues/24
-	// Note: This prefix must be all lower case.
-	stdinPrefix                = "hugostdin:"
 	dartSassEmbeddedBinaryName = "dart-sass-embedded"
 )
 
@@ -76,7 +72,7 @@ func (t *transform) Transform(ctx *resources.ResourceTransformationCtx) error {
 	}
 
 	baseDir := path.Dir(ctx.SourcePath)
-	filename := stdinPrefix
+	filename := dartSassStdinPrefix
 
 	if ctx.SourcePath != "" {
 		filename += t.c.sfs.RealFilename(ctx.SourcePath)
@@ -108,26 +104,6 @@ func (t *transform) Transform(ctx *resources.ResourceTransformationCtx) error {
 
 	res, err := t.c.toCSS(args, ctx.From)
 	if err != nil {
-		if sassErr, ok := err.(godartsass.SassError); ok {
-			start := sassErr.Span.Start
-			context := strings.TrimSpace(sassErr.Span.Context)
-			filename, _ := urlToFilename(sassErr.Span.Url)
-			if strings.HasPrefix(filename, stdinPrefix) {
-				filename = filename[len(stdinPrefix):]
-			}
-
-			offsetMatcher := func(m herrors.LineMatcher) int {
-				if m.Offset+len(m.Line) >= start.Offset && strings.Contains(m.Line, context) {
-					// We found the line, but return 0 to signal that we want to determine
-					// the column from the error.
-					return 0
-				}
-				return -1
-			}
-
-			return herrors.NewFileErrorFromFile(sassErr, filename, hugofs.Os, offsetMatcher)
-
-		}
 		return err
 	}
 
@@ -154,7 +130,7 @@ type importResolver struct {
 }
 
 func (t importResolver) CanonicalizeURL(url string) (string, error) {
-	filePath, isURL := urlToFilename(url)
+	filePath, isURL := paths.UrlToFilename(url)
 	var prevDir string
 	var pathDir string
 	if isURL {
@@ -200,23 +176,7 @@ func (t importResolver) CanonicalizeURL(url string) (string, error) {
 }
 
 func (t importResolver) Load(url string) (string, error) {
-	filename, _ := urlToFilename(url)
+	filename, _ := paths.UrlToFilename(url)
 	b, err := afero.ReadFile(hugofs.Os, filename)
 	return string(b), err
 }
-
-// TODO(bep) add tests
-func urlToFilename(urls string) (string, bool) {
-	u, err := url.ParseRequestURI(urls)
-	if err != nil {
-		return filepath.FromSlash(urls), false
-	}
-	p := filepath.FromSlash(u.Path)
-
-	if u.Host != "" {
-		// C:\data\file.txt
-		p = strings.ToUpper(u.Host) + ":" + p
-	}
-
-	return p, true
-}
diff --git a/resources/resource_transformers/tocss/scss/client_extended.go b/resources/resource_transformers/tocss/scss/client_extended.go
index c9b347c4c..bfee39499 100644
--- a/resources/resource_transformers/tocss/scss/client_extended.go
+++ b/resources/resource_transformers/tocss/scss/client_extended.go
@@ -47,6 +47,7 @@ func (c *Client) ToCSS(res resources.ResourceTransformer, opts Options) (resourc
 	}
 
 	return res.Transform(&toCSSTransformation{c: c, options: internalOptions})
+
 }
 
 type toCSSTransformation struct {
diff --git a/resources/resource_transformers/tocss/scss/integration_test.go b/resources/resource_transformers/tocss/scss/integration_test.go
index cbc7e192b..72c0fd988 100644
--- a/resources/resource_transformers/tocss/scss/integration_test.go
+++ b/resources/resource_transformers/tocss/scss/integration_test.go
@@ -14,6 +14,8 @@
 package scss_test
 
 import (
+	"path/filepath"
+	"strings"
 	"testing"
 
 	qt "github.com/frankban/quicktest"
@@ -133,7 +135,7 @@ moo {
 -- config.toml --
 theme = 'mytheme'
 -- layouts/index.html --
-{{ $cssOpts := (dict "includePaths" (slice "node_modules/foo" ) "transpiler" "dartsass" ) }}
+{{ $cssOpts := (dict "includePaths" (slice "node_modules/foo" ) ) }}
 {{ $r := resources.Get "scss/main.scss" |  toCSS $cssOpts  | minify  }}
 T1: {{ $r.Content }}
 -- themes/mytheme/assets/scss/components/_boo.scss --
@@ -171,3 +173,75 @@ zoo {
 
 	b.AssertFileContent("public/index.html", `T1: moo{color:#ccc}boo{color:green}zoo{color:pink}`)
 }
+
+func TestTransformErrors(t *testing.T) {
+	if !scss.Supports() {
+		t.Skip()
+	}
+
+	c := qt.New(t)
+
+	const filesTemplate = `
+-- config.toml --
+theme = 'mytheme'
+-- assets/scss/components/_foo.scss --
+/* comment line 1 */
+$foocolor: #ccc;
+
+foo {
+	color: $foocolor;
+}
+-- themes/mytheme/assets/scss/main.scss --
+/* comment line 1 */
+/* comment line 2 */
+@import "components/foo";
+/* comment line 4 */
+
+$maincolor: #eee;
+
+body {
+	color: $maincolor;
+}
+
+-- layouts/index.html --
+{{ $cssOpts := dict }}
+{{ $r := resources.Get "scss/main.scss" |  toCSS $cssOpts  | minify  }}
+T1: {{ $r.Content }}
+
+	`
+
+	c.Run("error in main", func(c *qt.C) {
+		b, err := hugolib.NewIntegrationTestBuilder(
+			hugolib.IntegrationTestConfig{
+				T:           c,
+				TxtarString: strings.Replace(filesTemplate, "$maincolor: #eee;", "$maincolor #eee;", 1),
+				NeedsOsFS:   true,
+			}).BuildE()
+
+		b.Assert(err, qt.IsNotNil)
+		b.Assert(err.Error(), qt.Contains, filepath.FromSlash(`themes/mytheme/assets/scss/main.scss:6:1": expected ':' after $maincolor in assignment statement`))
+		fe := b.AssertIsFileError(err)
+		b.Assert(fe.ErrorContext(), qt.IsNotNil)
+		b.Assert(fe.ErrorContext().Lines, qt.DeepEquals, []string{"/* comment line 4 */", "", "$maincolor #eee;", "", "body {"})
+		b.Assert(fe.ErrorContext().ChromaLexer, qt.Equals, "scss")
+
+	})
+
+	c.Run("error in import", func(c *qt.C) {
+		b, err := hugolib.NewIntegrationTestBuilder(
+			hugolib.IntegrationTestConfig{
+				T:           c,
+				TxtarString: strings.Replace(filesTemplate, "$foocolor: #ccc;", "$foocolor #ccc;", 1),
+				NeedsOsFS:   true,
+			}).BuildE()
+
+		b.Assert(err, qt.IsNotNil)
+		b.Assert(err.Error(), qt.Contains, filepath.FromSlash(`assets/scss/components/_foo.scss:2:1": expected ':' after $foocolor in assignment statement`))
+		fe := b.AssertIsFileError(err)
+		b.Assert(fe.ErrorContext(), qt.IsNotNil)
+		b.Assert(fe.ErrorContext().Lines, qt.DeepEquals, []string{"/* comment line 1 */", "$foocolor #ccc;", "", "foo {"})
+		b.Assert(fe.ErrorContext().ChromaLexer, qt.Equals, "scss")
+
+	})
+
+}
diff --git a/resources/resource_transformers/tocss/scss/tocss.go b/resources/resource_transformers/tocss/scss/tocss.go
index f9f4786f5..57ac16711 100644
--- a/resources/resource_transformers/tocss/scss/tocss.go
+++ b/resources/resource_transformers/tocss/scss/tocss.go
@@ -20,10 +20,13 @@ import (
 	"fmt"
 	"io"
 	"path"
+
 	"path/filepath"
 	"strings"
 
 	"github.com/bep/golibsass/libsass"
+	"github.com/bep/golibsass/libsass/libsasserrors"
+	"github.com/gohugoio/hugo/common/herrors"
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/hugofs"
 	"github.com/gohugoio/hugo/media"
@@ -136,7 +139,14 @@ func (t *toCSSTransformation) Transform(ctx *resources.ResourceTransformationCtx
 
 	res, err := t.c.toCSS(options.to, ctx.To, ctx.From)
 	if err != nil {
-		return err
+		if sasserr, ok := err.(libsasserrors.Error); ok {
+			if sasserr.File == "stdin" && ctx.SourcePath != "" {
+				sasserr.File = t.c.sfs.RealFilename(ctx.SourcePath)
+				err = sasserr
+			}
+		}
+		return herrors.NewFileErrorFromFileInErr(err, hugofs.Os, nil)
+
 	}
 
 	if options.from.EnableSourceMap && res.SourceMapContent != "" {
@@ -180,7 +190,7 @@ func (c *Client) toCSS(options libsass.Options, dst io.Writer, src io.Reader) (l
 
 	res, err = transpiler.Execute(in)
 	if err != nil {
-		return res, fmt.Errorf("SCSS processing failed: %w", err)
+		return res, err
 	}
 
 	out := res.CSS