Update blackfriday dependency per #2994 (#3857)

Signed-off-by: PJ Eby <pje@telecommunity.com>

9 files changed, 292 insertions, 110 deletions

diff --git a/vendor/github.com/russross/blackfriday/README.md b/vendor/github.com/russross/blackfriday/README.md
index 3c113cb102..e0066b0fc1 100644
--- a/vendor/github.com/russross/blackfriday/README.md
+++ b/vendor/github.com/russross/blackfriday/README.md
@@ -1,4 +1,6 @@
-Blackfriday [![Build Status](https://travis-ci.org/russross/blackfriday.svg?branch=master)](https://travis-ci.org/russross/blackfriday) [![GoDoc](https://godoc.org/github.com/russross/blackfriday?status.svg)](https://godoc.org/github.com/russross/blackfriday)
+Blackfriday
+[![Build Status][BuildSVG]][BuildURL]
+[![Godoc][GodocV2SVG]][GodocV2URL]
 ===========
 
 Blackfriday is a [Markdown][1] processor implemented in [Go][2]. It
@@ -8,7 +10,7 @@ punctuation substitutions, etc.), and it is safe for all utf-8
 (unicode) input.
 
 HTML output is currently supported, along with Smartypants
-extensions. An experimental LaTeX output engine is also included.
+extensions.
 
 It started as a translation from C of [Sundown][3].
 
@@ -16,26 +18,71 @@ It started as a translation from C of [Sundown][3].
 Installation
 ------------
 
-Blackfriday is compatible with Go 1. If you are using an older
-release of Go, consider using v1.1 of blackfriday, which was based
-on the last stable release of Go prior to Go 1. You can find it as a
-tagged commit on github.
+Blackfriday is compatible with any modern Go release. With Go and git installed:
 
-With Go 1 and git installed:
+    go get -u gopkg.in/russross/blackfriday.v2
 
-    go get github.com/russross/blackfriday
+will download, compile, and install the package into your `$GOPATH` directory
+hierarchy.
 
-will download, compile, and install the package into your `$GOPATH`
-directory hierarchy. Alternatively, you can achieve the same if you
-import it into a project:
 
-    import "github.com/russross/blackfriday"
+Versions
+--------
+
+Currently maintained and recommended version of Blackfriday is `v2`. It's being
+developed on its own branch: https://github.com/russross/blackfriday/tree/v2 and the
+documentation is available at
+https://godoc.org/gopkg.in/russross/blackfriday.v2.
+
+It is `go get`-able via [gopkg.in][6] at `gopkg.in/russross/blackfriday.v2`,
+but we highly recommend using package management tool like [dep][7] or
+[Glide][8] and make use of semantic versioning. With package management you
+should import `github.com/russross/blackfriday` and specify that you're using
+version 2.0.0.
+
+Version 2 offers a number of improvements over v1:
+
+* Cleaned up API
+* A separate call to [`Parse`][4], which produces an abstract syntax tree for
+  the document
+* Latest bug fixes
+* Flexibility to easily add your own rendering extensions
+
+Potential drawbacks:
+
+* Our benchmarks show v2 to be slightly slower than v1. Currently in the
+  ballpark of around 15%.
+* API breakage. If you can't afford modifying your code to adhere to the new API
+  and don't care too much about the new features, v2 is probably not for you.
+* Several bug fixes are trailing behind and still need to be forward-ported to
+  v2. See issue [#348](https://github.com/russross/blackfriday/issues/348) for
+  tracking.
+
+If you are still interested in the legacy `v1`, you can import it from
+`github.com/russross/blackfriday`. Documentation for the legacy v1 can be found
+here: https://godoc.org/github.com/russross/blackfriday
+
+### Known issue with `dep`
+
+There is a known problem with using Blackfriday v1 _transitively_ and `dep`.
+Currently `dep` prioritizes semver versions over anything else, and picks the
+latest one, plus it does not apply a `[[constraint]]` specifier to transitively
+pulled in packages. So if you're using something that uses Blackfriday v1, but
+that something does not use `dep` yet, you will get Blackfriday v2 pulled in and
+your first dependency will fail to build.
+
+There are couple of fixes for it, documented here:
+https://github.com/golang/dep/blob/master/docs/FAQ.md#how-do-i-constrain-a-transitive-dependencys-version
+
+Meanwhile, `dep` team is working on a more general solution to the constraints
+on transitive dependencies problem: https://github.com/golang/dep/issues/1124.
 
-and `go get` without parameters.
 
 Usage
 -----
 
+### v1
+
 For basic usage, it is as simple as getting your input into a byte
 slice and calling:
 
@@ -46,34 +93,57 @@ feature set, use this instead:
 
     output := blackfriday.MarkdownCommon(input)
 
+### v2
+
+For the most sensible markdown processing, it is as simple as getting your input
+into a byte slice and calling:
+
+```go
+output := blackfriday.Run(input)
+```
+
+Your input will be parsed and the output rendered with a set of most popular
+extensions enabled. If you want the most basic feature set, corresponding with
+the bare Markdown specification, use:
+
+```go
+output := blackfriday.Run(input, blackfriday.WithNoExtensions())
+```
+
 ### Sanitize untrusted content
 
 Blackfriday itself does nothing to protect against malicious content. If you are
-dealing with user-supplied markdown, we recommend running blackfriday's output
-through HTML sanitizer such as
-[Bluemonday](https://github.com/microcosm-cc/bluemonday).
+dealing with user-supplied markdown, we recommend running Blackfriday's output
+through HTML sanitizer such as [Bluemonday][5].
 
-Here's an example of simple usage of blackfriday together with bluemonday:
+Here's an example of simple usage of Blackfriday together with Bluemonday:
 
-``` go
+```go
 import (
     "github.com/microcosm-cc/bluemonday"
-    "github.com/russross/blackfriday"
+    "gopkg.in/russross/blackfriday.v2"
 )
 
 // ...
-unsafe := blackfriday.MarkdownCommon(input)
+unsafe := blackfriday.Run(input)
 html := bluemonday.UGCPolicy().SanitizeBytes(unsafe)
 ```
 
-### Custom options
+### Custom options, v1
 
 If you want to customize the set of options, first get a renderer
-(currently either the HTML or LaTeX output engines), then use it to
+(currently only the HTML output engine), then use it to
 call the more general `Markdown` function. For examples, see the
 implementations of `MarkdownBasic` and `MarkdownCommon` in
 `markdown.go`.
 
+### Custom options, v2
+
+If you want to customize the set of options, use `blackfriday.WithExtensions`,
+`blackfriday.WithRenderer` and `blackfriday.WithRefOverride`.
+
+### `blackfriday-tool`
+
 You can also check out `blackfriday-tool` for a more complete example
 of how to use it. Download and install it using:
 
@@ -93,6 +163,22 @@ installed in `$GOPATH/bin`.  This is a statically-linked binary that
 can be copied to wherever you need it without worrying about
 dependencies and library versions.
 
+### Sanitized anchor names
+
+Blackfriday includes an algorithm for creating sanitized anchor names
+corresponding to a given input text. This algorithm is used to create
+anchors for headings when `EXTENSION_AUTO_HEADER_IDS` is enabled. The
+algorithm has a specification, so that other packages can create
+compatible anchor names and links to those anchors.
+
+The specification is located at https://godoc.org/github.com/russross/blackfriday#hdr-Sanitized_Anchor_Names.
+
+[`SanitizedAnchorName`](https://godoc.org/github.com/russross/blackfriday#SanitizedAnchorName) exposes this functionality, and can be used to
+create compatible links to the anchor names generated by blackfriday.
+This algorithm is also implemented in a small standalone package at
+[`github.com/shurcooL/sanitized_anchor_name`](https://godoc.org/github.com/shurcooL/sanitized_anchor_name). It can be useful for clients
+that want a small package and don't need full functionality of blackfriday.
+
 
 Features
 --------
@@ -233,7 +319,7 @@ are a few of note:
 
 *   [github_flavored_markdown](https://godoc.org/github.com/shurcooL/github_flavored_markdown):
     provides a GitHub Flavored Markdown renderer with fenced code block
-    highlighting, clickable header anchor links.
+    highlighting, clickable heading anchor links.
 
     It's not customizable, and its goal is to produce HTML output
     equivalent to the [GitHub Markdown API endpoint](https://developer.github.com/v3/markdown/#render-a-markdown-document-in-raw-mode),
@@ -242,27 +328,18 @@ are a few of note:
 *   [markdownfmt](https://github.com/shurcooL/markdownfmt): like gofmt,
     but for markdown.
 
-*   LaTeX output: renders output as LaTeX. This is currently part of the
-    main Blackfriday repository, but may be split into its own project
-    in the future. If you are interested in owning and maintaining the
-    LaTeX output component, please be in touch.
-
-    It renders some basic documents, but is only experimental at this
-    point. In particular, it does not do any inline escaping, so input
-    that happens to look like LaTeX code will be passed through without
-    modification.
-    
-*   [Md2Vim](https://github.com/FooSoft/md2vim): transforms markdown files into vimdoc format.
+*   [LaTeX output](https://bitbucket.org/ambrevar/blackfriday-latex):
+    renders output as LaTeX.
 
 
-Todo
+TODO
 ----
 
 *   More unit testing
-*   Improve unicode support. It does not understand all unicode
+*   Improve Unicode support. It does not understand all Unicode
     rules (about what constitutes a letter, a punctuation symbol,
     etc.), so it may fail to detect word boundaries correctly in
-    some instances. It is safe on all utf-8 input.
+    some instances. It is safe on all UTF-8 input.
 
 
 License
@@ -271,6 +348,16 @@ License
 [Blackfriday is distributed under the Simplified BSD License](LICENSE.txt)
 
 
-   [1]: http://daringfireball.net/projects/markdown/ "Markdown"
-   [2]: http://golang.org/ "Go Language"
+   [1]: https://daringfireball.net/projects/markdown/ "Markdown"
+   [2]: https://golang.org/ "Go Language"
    [3]: https://github.com/vmg/sundown "Sundown"
+   [4]: https://godoc.org/gopkg.in/russross/blackfriday.v2#Parse "Parse func"
+   [5]: https://github.com/microcosm-cc/bluemonday "Bluemonday"
+   [6]: https://labix.org/gopkg.in "gopkg.in"
+   [7]: https://github.com/golang/dep/ "dep"
+   [8]: https://github.com/Masterminds/glide "Glide"
+
+   [BuildSVG]: https://travis-ci.org/russross/blackfriday.svg?branch=master
+   [BuildURL]: https://travis-ci.org/russross/blackfriday
+   [GodocV2SVG]: https://godoc.org/gopkg.in/russross/blackfriday.v2?status.svg
+   [GodocV2URL]: https://godoc.org/gopkg.in/russross/blackfriday.v2
diff --git a/vendor/github.com/russross/blackfriday/block.go b/vendor/github.com/russross/blackfriday/block.go
index 9cf451f0b3..929638aa48 100644
--- a/vendor/github.com/russross/blackfriday/block.go
+++ b/vendor/github.com/russross/blackfriday/block.go
@@ -15,8 +15,8 @@ package blackfriday
 
 import (
 	"bytes"
-
-	"github.com/shurcooL/sanitized_anchor_name"
+	"strings"
+	"unicode"
 )
 
 // Parse block-level data.
@@ -93,7 +93,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 
 		// fenced code block:
 		//
-		// ``` go
+		// ``` go info string here
 		// func fact(n int) int {
 		//     if n <= 1 {
 		//         return n
@@ -243,7 +243,7 @@ func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
 	}
 	if end > i {
 		if id == "" && p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
-			id = sanitized_anchor_name.Create(string(data[i:end]))
+			id = SanitizedAnchorName(string(data[i:end]))
 		}
 		work := func() bool {
 			p.inline(out, data[i:end])
@@ -563,7 +563,7 @@ func (*parser) isHRule(data []byte) bool {
 // and returns the end index if so, or 0 otherwise. It also returns the marker found.
 // If syntax is not nil, it gets set to the syntax specified in the fence line.
 // A final newline is mandatory to recognize the fence line, unless newlineOptional is true.
-func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional bool) (end int, marker string) {
+func isFenceLine(data []byte, info *string, oldmarker string, newlineOptional bool) (end int, marker string) {
 	i, size := 0, 0
 
 	// skip up to three spaces
@@ -599,9 +599,9 @@ func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional
 	}
 
 	// TODO(shurcooL): It's probably a good idea to simplify the 2 code paths here
-	// into one, always get the syntax, and discard it if the caller doesn't care.
-	if syntax != nil {
-		syn := 0
+	// into one, always get the info string, and discard it if the caller doesn't care.
+	if info != nil {
+		infoLength := 0
 		i = skipChar(data, i, ' ')
 
 		if i >= len(data) {
@@ -611,14 +611,14 @@ func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional
 			return 0, ""
 		}
 
-		syntaxStart := i
+		infoStart := i
 
 		if data[i] == '{' {
 			i++
-			syntaxStart++
+			infoStart++
 
 			for i < len(data) && data[i] != '}' && data[i] != '\n' {
-				syn++
+				infoLength++
 				i++
 			}
 
@@ -628,24 +628,24 @@ func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional
 
 			// strip all whitespace at the beginning and the end
 			// of the {} block
-			for syn > 0 && isspace(data[syntaxStart]) {
-				syntaxStart++
-				syn--
+			for infoLength > 0 && isspace(data[infoStart]) {
+				infoStart++
+				infoLength--
 			}
 
-			for syn > 0 && isspace(data[syntaxStart+syn-1]) {
-				syn--
+			for infoLength > 0 && isspace(data[infoStart+infoLength-1]) {
+				infoLength--
 			}
 
 			i++
 		} else {
-			for i < len(data) && !isspace(data[i]) {
-				syn++
+			for i < len(data) && !isverticalspace(data[i]) {
+				infoLength++
 				i++
 			}
 		}
 
-		*syntax = string(data[syntaxStart : syntaxStart+syn])
+		*info = strings.TrimSpace(string(data[infoStart : infoStart+infoLength]))
 	}
 
 	i = skipChar(data, i, ' ')
@@ -663,8 +663,8 @@ func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional
 // or 0 otherwise. It writes to out if doRender is true, otherwise it has no side effects.
 // If doRender is true, a final newline is mandatory to recognize the fenced code block.
 func (p *parser) fencedCodeBlock(out *bytes.Buffer, data []byte, doRender bool) int {
-	var syntax string
-	beg, marker := isFenceLine(data, &syntax, "", false)
+	var infoString string
+	beg, marker := isFenceLine(data, &infoString, "", false)
 	if beg == 0 || beg >= len(data) {
 		return 0
 	}
@@ -698,7 +698,7 @@ func (p *parser) fencedCodeBlock(out *bytes.Buffer, data []byte, doRender bool)
 	}
 
 	if doRender {
-		p.r.BlockCode(out, work.Bytes(), syntax)
+		p.r.BlockCode(out, work.Bytes(), infoString)
 	}
 
 	return beg
@@ -1364,7 +1364,7 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 
 				id := ""
 				if p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
-					id = sanitized_anchor_name.Create(string(data[prev:eol]))
+					id = SanitizedAnchorName(string(data[prev:eol]))
 				}
 
 				p.r.Header(out, work, level, id)
@@ -1428,3 +1428,24 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 	p.renderParagraph(out, data[:i])
 	return i
 }
+
+// SanitizedAnchorName returns a sanitized anchor name for the given text.
+//
+// It implements the algorithm specified in the package comment.
+func SanitizedAnchorName(text string) string {
+	var anchorName []rune
+	futureDash := false
+	for _, r := range text {
+		switch {
+		case unicode.IsLetter(r) || unicode.IsNumber(r):
+			if futureDash && len(anchorName) > 0 {
+				anchorName = append(anchorName, '-')
+			}
+			futureDash = false
+			anchorName = append(anchorName, unicode.ToLower(r))
+		default:
+			futureDash = true
+		}
+	}
+	return string(anchorName)
+}
diff --git a/vendor/github.com/russross/blackfriday/doc.go b/vendor/github.com/russross/blackfriday/doc.go
new file mode 100644
index 0000000000..9656c42a19
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/doc.go
@@ -0,0 +1,32 @@
+// Package blackfriday is a Markdown processor.
+//
+// It translates plain text with simple formatting rules into HTML or LaTeX.
+//
+// Sanitized Anchor Names
+//
+// Blackfriday includes an algorithm for creating sanitized anchor names
+// corresponding to a given input text. This algorithm is used to create
+// anchors for headings when EXTENSION_AUTO_HEADER_IDS is enabled. The
+// algorithm is specified below, so that other packages can create
+// compatible anchor names and links to those anchors.
+//
+// The algorithm iterates over the input text, interpreted as UTF-8,
+// one Unicode code point (rune) at a time. All runes that are letters (category L)
+// or numbers (category N) are considered valid characters. They are mapped to
+// lower case, and included in the output. All other runes are considered
+// invalid characters. Invalid characters that preceed the first valid character,
+// as well as invalid character that follow the last valid character
+// are dropped completely. All other sequences of invalid characters
+// between two valid characters are replaced with a single dash character '-'.
+//
+// SanitizedAnchorName exposes this functionality, and can be used to
+// create compatible links to the anchor names generated by blackfriday.
+// This algorithm is also implemented in a small standalone package at
+// github.com/shurcooL/sanitized_anchor_name. It can be useful for clients
+// that want a small package and don't need full functionality of blackfriday.
+package blackfriday
+
+// NOTE: Keep Sanitized Anchor Name algorithm in sync with package
+//       github.com/shurcooL/sanitized_anchor_name.
+//       Otherwise, users of sanitized_anchor_name will get anchor names
+//       that are incompatible with those generated by blackfriday.
diff --git a/vendor/github.com/russross/blackfriday/html.go b/vendor/github.com/russross/blackfriday/html.go
index 74e67ee82b..e0a6c69c96 100644
--- a/vendor/github.com/russross/blackfriday/html.go
+++ b/vendor/github.com/russross/blackfriday/html.go
@@ -42,6 +42,7 @@ const (
 	HTML_SMARTYPANTS_DASHES                    // enable smart dashes (with HTML_USE_SMARTYPANTS)
 	HTML_SMARTYPANTS_LATEX_DASHES              // enable LaTeX-style dashes (with HTML_USE_SMARTYPANTS and HTML_SMARTYPANTS_DASHES)
 	HTML_SMARTYPANTS_ANGLED_QUOTES             // enable angled double quotes (with HTML_USE_SMARTYPANTS) for double quotes rendering
+	HTML_SMARTYPANTS_QUOTES_NBSP               // enable "French guillemets" (with HTML_USE_SMARTYPANTS)
 	HTML_FOOTNOTE_RETURN_LINKS                 // generate a link at the end of a footnote to return to the source
 )
 
@@ -254,33 +255,21 @@ func (options *Html) HRule(out *bytes.Buffer) {
 	out.WriteByte('\n')
 }
 
-func (options *Html) BlockCode(out *bytes.Buffer, text []byte, lang string) {
+func (options *Html) BlockCode(out *bytes.Buffer, text []byte, info string) {
 	doubleSpace(out)
 
-	// parse out the language names/classes
-	count := 0
-	for _, elt := range strings.Fields(lang) {
-		if elt[0] == '.' {
-			elt = elt[1:]
-		}
-		if len(elt) == 0 {
-			continue
-		}
-		if count == 0 {
-			out.WriteString("<pre><code class=\"language-")
-		} else {
-			out.WriteByte(' ')
-		}
-		attrEscape(out, []byte(elt))
-		count++
+	endOfLang := strings.IndexAny(info, "\t ")
+	if endOfLang < 0 {
+		endOfLang = len(info)
 	}
-
-	if count == 0 {
+	lang := info[:endOfLang]
+	if len(lang) == 0 || lang == "." {
 		out.WriteString("<pre><code>")
 	} else {
+		out.WriteString("<pre><code class=\"language-")
+		attrEscape(out, []byte(lang))
 		out.WriteString("\">")
 	}
-
 	attrEscape(out, text)
 	out.WriteString("</code></pre>\n")
 }
@@ -619,7 +608,7 @@ func (options *Html) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
 	out.WriteString(`fnref:`)
 	out.WriteString(options.parameters.FootnoteAnchorPrefix)
 	out.Write(slug)
-	out.WriteString(`"><a rel="footnote" href="#`)
+	out.WriteString(`"><a href="#`)
 	out.WriteString(`fn:`)
 	out.WriteString(options.parameters.FootnoteAnchorPrefix)
 	out.Write(slug)
diff --git a/vendor/github.com/russross/blackfriday/inline.go b/vendor/github.com/russross/blackfriday/inline.go
index cb00ed68e0..4483b8f19f 100644
--- a/vendor/github.com/russross/blackfriday/inline.go
+++ b/vendor/github.com/russross/blackfriday/inline.go
@@ -170,6 +170,10 @@ func lineBreak(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 	precededByBackslash := offset >= 1 && data[offset-1] == '\\' // see http://spec.commonmark.org/0.18/#example-527
 	precededByBackslash = precededByBackslash && p.flags&EXTENSION_BACKSLASH_LINE_BREAK != 0
 
+	if p.flags&EXTENSION_JOIN_LINES != 0 {
+		return 1
+	}
+
 	// should there be a hard line break here?
 	if p.flags&EXTENSION_HARD_LINE_BREAK == 0 && !precededByTwoSpaces && !precededByBackslash {
 		return 0
@@ -484,6 +488,7 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 			}
 
 			p.notes = append(p.notes, ref)
+			p.notesRecord[string(ref.link)] = struct{}{}
 
 			link = ref.link
 			title = ref.title
@@ -494,9 +499,10 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 				return 0
 			}
 
-			if t == linkDeferredFootnote {
+			if t == linkDeferredFootnote && !p.isFootnote(lr) {
 				lr.noteId = len(p.notes) + 1
 				p.notes = append(p.notes, lr)
+				p.notesRecord[string(lr.link)] = struct{}{}
 			}
 
 			// keep link and title from reference
diff --git a/vendor/github.com/russross/blackfriday/latex.go b/vendor/github.com/russross/blackfriday/latex.go
index 70705aa9c1..3d30d09474 100644
--- a/vendor/github.com/russross/blackfriday/latex.go
+++ b/vendor/github.com/russross/blackfriday/latex.go
@@ -17,6 +17,7 @@ package blackfriday
 
 import (
 	"bytes"
+	"strings"
 )
 
 // Latex is a type that implements the Renderer interface for LaTeX output.
@@ -39,16 +40,17 @@ func (options *Latex) GetFlags() int {
 }
 
 // render code chunks using verbatim, or listings if we have a language
-func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, lang string) {
-	if lang == "" {
+func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, info string) {
+	if info == "" {
 		out.WriteString("\n\\begin{verbatim}\n")
 	} else {
+		lang := strings.Fields(info)[0]
 		out.WriteString("\n\\begin{lstlisting}[language=")
 		out.WriteString(lang)
 		out.WriteString("]\n")
 	}
 	out.Write(text)
-	if lang == "" {
+	if info == "" {
 		out.WriteString("\n\\end{verbatim}\n")
 	} else {
 		out.WriteString("\n\\end{lstlisting}\n")
diff --git a/vendor/github.com/russross/blackfriday/markdown.go b/vendor/github.com/russross/blackfriday/markdown.go
index 58ba68ded3..41595d62d0 100644
--- a/vendor/github.com/russross/blackfriday/markdown.go
+++ b/vendor/github.com/russross/blackfriday/markdown.go
@@ -13,9 +13,6 @@
 //
 //
 
-// Blackfriday markdown processor.
-//
-// Translates plain text with simple formatting rules into HTML or LaTeX.
 package blackfriday
 
 import (
@@ -46,6 +43,7 @@ const (
 	EXTENSION_AUTO_HEADER_IDS                        // Create the header ID from the text
 	EXTENSION_BACKSLASH_LINE_BREAK                   // translate trailing backslashes into line breaks
 	EXTENSION_DEFINITION_LISTS                       // render definition lists
+	EXTENSION_JOIN_LINES                             // delete newline and join lines
 
 	commonHtmlFlags = 0 |
 		HTML_USE_XHTML |
@@ -161,7 +159,7 @@ var blockTags = map[string]struct{}{
 // Currently Html and Latex implementations are provided
 type Renderer interface {
 	// block-level callbacks
-	BlockCode(out *bytes.Buffer, text []byte, lang string)
+	BlockCode(out *bytes.Buffer, text []byte, infoString string)
 	BlockQuote(out *bytes.Buffer, text []byte)
 	BlockHtml(out *bytes.Buffer, text []byte)
 	Header(out *bytes.Buffer, text func() bool, level int, id string)
@@ -220,7 +218,8 @@ type parser struct {
 	// Footnotes need to be ordered as well as available to quickly check for
 	// presence. If a ref is also a footnote, it's stored both in refs and here
 	// in notes. Slice is nil if footnotes not enabled.
-	notes []*reference
+	notes       []*reference
+	notesRecord map[string]struct{}
 }
 
 func (p *parser) getRef(refid string) (ref *reference, found bool) {
@@ -243,6 +242,11 @@ func (p *parser) getRef(refid string) (ref *reference, found bool) {
 	return ref, found
 }
 
+func (p *parser) isFootnote(ref *reference) bool {
+	_, ok := p.notesRecord[string(ref.link)]
+	return ok
+}
+
 //
 //
 // Public interface
@@ -378,6 +382,7 @@ func MarkdownOptions(input []byte, renderer Renderer, opts Options) []byte {
 
 	if extensions&EXTENSION_FOOTNOTES != 0 {
 		p.notes = make([]*reference, 0)
+		p.notesRecord = make(map[string]struct{})
 	}
 
 	first := firstPass(p, input)
@@ -799,7 +804,17 @@ func ispunct(c byte) bool {
 
 // Test if a character is a whitespace character.
 func isspace(c byte) bool {
-	return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v'
+	return ishorizontalspace(c) || isverticalspace(c)
+}
+
+// Test if a character is a horizontal whitespace character.
+func ishorizontalspace(c byte) bool {
+	return c == ' ' || c == '\t'
+}
+
+// Test if a character is a vertical whitespace character.
+func isverticalspace(c byte) bool {
+	return c == '\n' || c == '\r' || c == '\f' || c == '\v'
 }
 
 // Test if a character is letter.
diff --git a/vendor/github.com/russross/blackfriday/smartypants.go b/vendor/github.com/russross/blackfriday/smartypants.go
index eeffa5e1e1..f25bd07d95 100644
--- a/vendor/github.com/russross/blackfriday/smartypants.go
+++ b/vendor/github.com/russross/blackfriday/smartypants.go
@@ -39,7 +39,7 @@ func isdigit(c byte) bool {
 	return c >= '0' && c <= '9'
 }
 
-func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote byte, isOpen *bool) bool {
+func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote byte, isOpen *bool, addNBSP bool) bool {
 	// edge of the buffer is likely to be a tag that we don't get to see,
 	// so we treat it like text sometimes
 
@@ -96,6 +96,12 @@ func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote
 		*isOpen = false
 	}
 
+	// Note that with the limited lookahead, this non-breaking
+	// space will also be appended to single double quotes.
+	if addNBSP && !*isOpen {
+		out.WriteString("&nbsp;")
+	}
+
 	out.WriteByte('&')
 	if *isOpen {
 		out.WriteByte('l')
@@ -104,6 +110,11 @@ func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote
 	}
 	out.WriteByte(quote)
 	out.WriteString("quo;")
+
+	if addNBSP && *isOpen {
+		out.WriteString("&nbsp;")
+	}
+
 	return true
 }
 
@@ -116,7 +127,7 @@ func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byt
 			if len(text) >= 3 {
 				nextChar = text[2]
 			}
-			if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote) {
+			if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote, false) {
 				return 1
 			}
 		}
@@ -141,7 +152,7 @@ func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byt
 	if len(text) > 1 {
 		nextChar = text[1]
 	}
-	if smartQuoteHelper(out, previousChar, nextChar, 's', &smrt.inSingleQuote) {
+	if smartQuoteHelper(out, previousChar, nextChar, 's', &smrt.inSingleQuote, false) {
 		return 0
 	}
 
@@ -205,13 +216,13 @@ func smartDashLatex(out *bytes.Buffer, smrt *smartypantsData, previousChar byte,
 	return 0
 }
 
-func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte) int {
+func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte, addNBSP bool) int {
 	if bytes.HasPrefix(text, []byte("&quot;")) {
 		nextChar := byte(0)
 		if len(text) >= 7 {
 			nextChar = text[6]
 		}
-		if smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote) {
+		if smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote, addNBSP) {
 			return 5
 		}
 	}
@@ -224,12 +235,15 @@ func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte
 	return 0
 }
 
-func smartAmp(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartAmpVariant(out, smrt, previousChar, text, 'd')
-}
+func smartAmp(angledQuotes, addNBSP bool) func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+	var quote byte = 'd'
+	if angledQuotes {
+		quote = 'a'
+	}
 
-func smartAmpAngledQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartAmpVariant(out, smrt, previousChar, text, 'a')
+	return func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+		return smartAmpVariant(out, smrt, previousChar, text, quote, addNBSP)
+	}
 }
 
 func smartPeriod(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
@@ -253,7 +267,7 @@ func smartBacktick(out *bytes.Buffer, smrt *smartypantsData, previousChar byte,
 		if len(text) >= 3 {
 			nextChar = text[2]
 		}
-		if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote) {
+		if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote, false) {
 			return 1
 		}
 	}
@@ -337,7 +351,7 @@ func smartDoubleQuoteVariant(out *bytes.Buffer, smrt *smartypantsData, previousC
 	if len(text) > 1 {
 		nextChar = text[1]
 	}
-	if !smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote) {
+	if !smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote, false) {
 		out.WriteString("&quot;")
 	}
 
@@ -367,14 +381,30 @@ type smartCallback func(out *bytes.Buffer, smrt *smartypantsData, previousChar b
 
 type smartypantsRenderer [256]smartCallback
 
+var (
+	smartAmpAngled      = smartAmp(true, false)
+	smartAmpAngledNBSP  = smartAmp(true, true)
+	smartAmpRegular     = smartAmp(false, false)
+	smartAmpRegularNBSP = smartAmp(false, true)
+)
+
 func smartypants(flags int) *smartypantsRenderer {
 	r := new(smartypantsRenderer)
+	addNBSP := flags&HTML_SMARTYPANTS_QUOTES_NBSP != 0
 	if flags&HTML_SMARTYPANTS_ANGLED_QUOTES == 0 {
 		r['"'] = smartDoubleQuote
-		r['&'] = smartAmp
+		if !addNBSP {
+			r['&'] = smartAmpRegular
+		} else {
+			r['&'] = smartAmpRegularNBSP
+		}
 	} else {
 		r['"'] = smartAngledDoubleQuote
-		r['&'] = smartAmpAngledQuote
+		if !addNBSP {
+			r['&'] = smartAmpAngled
+		} else {
+			r['&'] = smartAmpAngledNBSP
+		}
 	}
 	r['\''] = smartSingleQuote
 	r['('] = smartParens
diff --git a/vendor/vendor.json b/vendor/vendor.json
index 7d4cf1aa45..631336ac80 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -1174,10 +1174,10 @@
 			"revisionTime": "2016-09-12T16:18:15Z"
 		},
 		{
-			"checksumSHA1": "c7jHQZk5ZEsFR9EXsWJXkszPBZA=",
+			"checksumSHA1": "Ne3D+KJs1TU2trnDy1UCSwlXbAE=",
 			"path": "github.com/russross/blackfriday",
-			"revision": "5f33e7b7878355cd2b7e6b8eefc48a5472c69f70",
-			"revisionTime": "2016-10-03T16:27:22Z"
+			"revision": "11635eb403ff09dbc3a6b5a007ab5ab09151c229",
+			"revisionTime": "2018-04-28T10:25:19Z"
 		},
 		{
 			"checksumSHA1": "zmC8/3V4ls53DJlNTKDZwPSC/dA=",