Report markdown error filename

pages/file_test.go

@@ -1,6 +1,8 @@
 package pages
 
 import (
+	"bytes"
+	"fmt"
 	"io"
 	"testing"
 
@@ -21,11 +23,15 @@ func (s siteFake) RendererManager() renderers.Renderers { return &renderManagerF
 
 type renderManagerFake struct{ t *testing.T }
 
-func (rm renderManagerFake) ApplyLayout(layout string, src []byte, vars liquid.Bindings) ([]byte, error) {
+func (rm renderManagerFake) ApplyLayout(layout string, content []byte, vars liquid.Bindings) ([]byte, error) {
 	require.Equal(rm.t, "layout1", layout)
-	return nil, nil
+	return content, nil
 }
+
 func (rm renderManagerFake) Render(w io.Writer, src []byte, vars liquid.Bindings, filename string, lineNo int) error {
+	if bytes.Contains(src, []byte("{% error %}")) {
+		return fmt.Errorf("render error")
+	}
 	_, err := io.WriteString(w, "rendered: ")
 	if err != nil {
 		return err

pages/page.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/osteele/gojekyll/frontmatter"
+	"github.com/osteele/gojekyll/utils"
 	"github.com/osteele/gojekyll/version"
 	"github.com/osteele/liquid/evaluator"
 )
@@ -169,24 +170,23 @@ func (f *file) PostDate() time.Time {
 
 // Write applies Liquid and Markdown, as appropriate.
 func (p *page) Write(w io.Writer) error {
-	err := p.Render()
-	if err != nil {
+	if err := p.Render(); err != nil {
 		return err
 	}
 	p.RLock()
 	defer p.RUnlock()
-	content := p.content
-	layout, ok := p.frontMatter["layout"].(string)
-	if ok && layout != "" {
-		rp := p.site.RendererManager()
-		b, e := rp.ApplyLayout(layout, []byte(content), p.TemplateContext())
-		if e != nil {
-			return e
+	cn := p.content
+	lo, ok := p.frontMatter["layout"].(string)
+	if ok && lo != "" {
+		rm := p.site.RendererManager()
+		b, err := rm.ApplyLayout(lo, []byte(cn), p.TemplateContext())
+		if err != nil {
+			return err
 		}
 		_, err = w.Write(b)
-	} else {
-		_, err = io.WriteString(w, content)
+		return err
 	}
+	_, err := io.WriteString(w, cn)
 	return err
 }
 
@@ -197,7 +197,7 @@ func (p *page) Render() error {
 		p.Lock()
 		defer p.Unlock()
 		p.content = cn
-		p.contentError = err
+		p.contentError = utils.WrapPathError(err, p.filename)
 		p.excerpt = ex
 		p.rendered = true
 	})

pages/page_test.go

@@ -2,10 +2,14 @@ package pages
 
 import (
 	"bytes"
+	"io/ioutil"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/osteele/gojekyll/config"
+	"github.com/osteele/gojekyll/frontmatter"
+	"github.com/osteele/gojekyll/utils"
 	"github.com/stretchr/testify/require"
 )
 
@@ -27,17 +31,43 @@ func TestPage_TemplateContext(t *testing.T) {
 
 func TestPage_Categories(t *testing.T) {
 	s := siteFake{t, config.Default()}
-	fm := map[string]interface{}{"categories": "b a"}
+	fm := frontmatter.FrontMatter{"categories": "b a"}
 	f := file{site: s, frontMatter: fm}
 	p := page{file: f}
 	require.Equal(t, []string{"a", "b"}, p.Categories())
 }
 
 func TestPage_Write(t *testing.T) {
-	cfg := config.Default()
-	p, err := NewFile(siteFake{t, cfg}, "testdata/page_with_layout.md", "page_with_layout.md", map[string]interface{}{})
+	t.Run("rendering", func(t *testing.T) {
+		p := requirePageFromFile(t, "page_with_layout.md")
+		buf := new(bytes.Buffer)
+		require.NoError(t, p.Write(buf))
+		require.Contains(t, buf.String(), "page with layout")
+	})
+
+	t.Run("rendering error", func(t *testing.T) {
+		p := requirePageFromFile(t, "liquid_error.md")
+		err := p.Write(ioutil.Discard)
+		require.NotNil(t, err)
+		require.Contains(t, err.Error(), "render error")
+		pe, ok := err.(utils.PathError)
+		require.True(t, ok)
+		require.Equal(t, "testdata/liquid_error.md", pe.Path())
+	})
+}
+
+func fakePageFromFile(t *testing.T, file string) (Document, error) {
+	return NewFile(
+		siteFake{t, config.Default()},
+		filepath.Join("testdata", file),
+		file,
+		frontmatter.FrontMatter{},
+	)
+}
+
+func requirePageFromFile(t *testing.T, file string) Document {
+	p, err := fakePageFromFile(t, file)
 	require.NoError(t, err)
 	require.NotNil(t, p)
-	buf := new(bytes.Buffer)
-	require.NoError(t, p.Write(buf))
+	return p
 }

pages/testdata/liquid_error.md

@@ -0,0 +1,4 @@
+---
+---
+
+{% error %}

renderers/layouts.go

@@ -13,8 +13,8 @@ import (
 	"github.com/osteele/liquid"
 )
 
-// ApplyLayout applies the named layout to the data.
-func (p *Manager) ApplyLayout(name string, data []byte, vars liquid.Bindings) ([]byte, error) {
+// ApplyLayout applies the named layout to the content.
+func (p *Manager) ApplyLayout(name string, content []byte, vars liquid.Bindings) ([]byte, error) {
 	for name != "" {
 		var lfm map[string]interface{}
 		tpl, err := p.FindLayout(name, &lfm)
@@ -22,16 +22,16 @@ func (p *Manager) ApplyLayout(name string, data []byte, vars liquid.Bindings) ([
 			return nil, err
 		}
 		b := utils.MergeStringMaps(vars, map[string]interface{}{
-			"content": string(data),
+			"content": string(content),
 			"layout":  lfm,
 		})
-		data, err = tpl.Render(b)
+		content, err = tpl.Render(b)
 		if err != nil {
 			return nil, utils.WrapPathError(err, name)
 		}
 		name = templates.VariableMap(lfm).String("layout", "")
 	}
-	return data, nil
+	return content, nil
 }
 
 // FindLayout returns a template for the named layout.

renderers/markdown.go

@@ -2,6 +2,7 @@ package renderers
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"regexp"
 
@@ -29,17 +30,31 @@ const blackfridayExtensions = 0 |
 	// added relative to commonExtensions
 	blackfriday.EXTENSION_AUTO_HEADER_IDS
 
-func renderMarkdown(md []byte) []byte {
+func renderMarkdown(md []byte) ([]byte, error) {
 	renderer := blackfriday.HtmlRenderer(blackfridayFlags, "", "")
-	html := blackfriday.MarkdownOptions(md, renderer, blackfriday.Options{
-		Extensions: blackfridayExtensions})
+	html := blackfriday.MarkdownOptions(
+		md,
+		renderer,
+		blackfriday.Options{Extensions: blackfridayExtensions},
+	)
 	html, err := renderInnerMarkdown(html)
 	if err != nil {
-		panic(err)
+		return nil, fmt.Errorf("%s while rendering markdown", err)
 	}
-	return html
+	return html, nil
 }
 
+func _renderMarkdown(md []byte) ([]byte, error) {
+	renderer := blackfriday.HtmlRenderer(blackfridayFlags, "", "")
+	html := blackfriday.MarkdownOptions(
+		md,
+		renderer,
+		blackfriday.Options{Extensions: blackfridayExtensions},
+	)
+	return html, nil
+}
+
+// search HTML for markdown=1, and process if found
 func renderInnerMarkdown(b []byte) ([]byte, error) {
 	z := html.NewTokenizer(bytes.NewReader(b))
 	buf := new(bytes.Buffer)
@@ -54,7 +69,7 @@ outer:
 			return nil, z.Err()
 		case html.StartTagToken:
 			if hasMarkdownAttr(z) {
-				_, err := buf.Write(removeMarkdownAttr(z.Raw()))
+				_, err := buf.Write(stripMarkdownAttr(z.Raw()))
 				if err != nil {
 					return nil, err
 				}
@@ -62,6 +77,7 @@ outer:
 					return nil, err
 				}
 				// the above leaves z set to the end token
+				// fall through to render it
 			}
 		}
 		_, err := buf.Write(z.Raw())
@@ -72,8 +88,6 @@ outer:
 	return buf.Bytes(), nil
 }
 
-var markdownAttrRE = regexp.MustCompile(`\s*markdown\s*=\s*("1"|'1'|1)\s*`)
-
 func hasMarkdownAttr(z *html.Tokenizer) bool {
 	for {
 		k, v, more := z.TagAttr()
@@ -86,12 +100,18 @@ func hasMarkdownAttr(z *html.Tokenizer) bool {
 	}
 }
 
-func removeMarkdownAttr(tag []byte) []byte {
+var markdownAttrRE = regexp.MustCompile(`\s*markdown\s*=[^\s>]*\s*`)
+
+// return the text of a start tag, w/out the markdown attribute
+func stripMarkdownAttr(tag []byte) []byte {
 	tag = markdownAttrRE.ReplaceAll(tag, []byte(" "))
 	tag = bytes.Replace(tag, []byte(" >"), []byte(">"), 1)
 	return tag
 }
 
+// called once markdown="1" attribute is detected.
+// Collects the HTML tokens into a string, applies markdown to them,
+// and writes the result
 func processInnerMarkdown(w io.Writer, z *html.Tokenizer) error {
 	buf := new(bytes.Buffer)
 	depth := 1
@@ -111,10 +131,13 @@ loop:
 		}
 		_, err := buf.Write(z.Raw())
 		if err != nil {
-			panic(err)
+			return err
 		}
 	}
-	html := renderMarkdown(buf.Bytes())
-	_, err := w.Write(html)
+	html, err := _renderMarkdown(buf.Bytes())
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(html)
 	return err
 }

renderers/markdown_test.go

@@ -1,19 +1,35 @@
 package renderers
 
 import (
+	"log"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
-func renderMarkdownString(s string) string {
-	return string(renderMarkdown([]byte(s)))
+func TestRenderMarkdown(t *testing.T) {
+	require.Equal(t, "<p><em>b</em></p>\n", mustMarkdownString("*b*"))
+	require.Equal(t, "<div>*b*</div>\n", mustMarkdownString("<div>*b*</div>"))
+	require.Equal(t, "<div a=1><p><em>b</em></p>\n</div>\n", mustMarkdownString(`<div a=1 markdown="1">*b*</div>`))
+	require.Equal(t, "<div a=1><p><em>b</em></p>\n</div>\n", mustMarkdownString(`<div a=1 markdown='1'>*b*</div>`))
+	require.Equal(t, "<div a=1><p><em>b</em></p>\n</div>\n", mustMarkdownString(`<div a=1 markdown=1>*b*</div>`))
+
+	_, err := renderMarkdownString(`<div a=1 markdown=1><p></div>`)
+	require.NotNil(t, err)
 }
 
-func TestRenderMarkdown(t *testing.T) {
-	require.Equal(t, "<p><em>b</em></p>\n", renderMarkdownString("*b*"))
-	require.Equal(t, "<div>*b*</div>\n", renderMarkdownString("<div>*b*</div>"))
-	require.Equal(t, "<div a=1><p><em>b</em></p>\n</div>\n", renderMarkdownString(`<div a=1 markdown="1">*b*</div>`))
-	require.Equal(t, "<div a=1><p><em>b</em></p>\n</div>\n", renderMarkdownString(`<div a=1 markdown='1'>*b*</div>`))
-	require.Equal(t, "<div a=1><p><em>b</em></p>\n</div>\n", renderMarkdownString(`<div a=1 markdown=1>*b*</div>`))
+func mustMarkdownString(md string) string {
+	s, err := renderMarkdown([]byte(md))
+	if err != nil {
+		log.Fatal(err)
+	}
+	return string(s)
+}
+
+func renderMarkdownString(md string) (string, error) {
+	s, err := renderMarkdown([]byte(md))
+	if err != nil {
+		return "", err
+	}
+	return string(s), err
 }

renderers/renderers.go

@@ -64,7 +64,10 @@ func (p *Manager) Render(w io.Writer, src []byte, vars liquid.Bindings, filename
 		return err
 	}
 	if p.cfg.IsMarkdown(filename) {
-		src = renderMarkdown(src)
+		src, err = renderMarkdown(src)
+		if err != nil {
+			return err
+		}
 	}
 	_, err = w.Write(src)
 	return err

utils/errors.go

@@ -19,8 +19,12 @@ type pathError struct {
 	path  string
 }
 
-func (p *pathError) Error() string {
-	return fmt.Sprintf("%s: %s", p.path, p.cause)
+func (pe *pathError) Error() string {
+	return fmt.Sprintf("%s: %s", pe.path, pe.cause)
+}
+
+func (pe *pathError) Path() string {
+	return pe.path
 }
 
 // WrapPathError returns an error that will print with a path.\