Auto merge of #44238 - nrc:pulldown-warn, r=@QuietMisdreavus

Improve the Pulldown/hoedown warnings cc #44229 r? @QuietMisdreavus

Author: bors

src/librustdoc/html/render.rs

@@ -63,7 +63,7 @@ use rustc::util::nodemap::{FxHashMap, FxHashSet};
 use rustc::session::config::nightly_options::is_nightly_build;
 use rustc_data_structures::flock;
 
-use clean::{self, AttributesExt, GetDefId, SelfTy, Mutability};
+use clean::{self, AttributesExt, GetDefId, SelfTy, Mutability, Span};
 use doctree;
 use fold::DocFolder;
 use html::escape::Escape;
@@ -124,6 +124,9 @@ pub struct SharedContext {
  /// The given user css file which allow to customize the generated
  /// documentation theme.
  pub css_file_extension: Option<PathBuf>,
+ /// Warnings for the user if rendering would differ using different markdown
+ /// parsers.
+ pub markdown_warnings: RefCell<Vec<(Span, String, Vec<html_diff::Difference>)>>,
 }
 
 /// Indicates where an external crate can be found.
@@ -457,6 +460,7 @@ pub fn run(mut krate: clean::Crate,
  krate: krate.name.clone(),
  },
  css_file_extension: css_file_extension.clone(),
+ markdown_warnings: RefCell::new(vec![]),
  };
 
  // If user passed in `--playground-url` arg, we fill in crate name here
@@ -579,8 +583,102 @@ pub fn run(mut krate: clean::Crate,
 
  write_shared(&cx, &krate, &*cache, index)?;
 
+ let scx = cx.shared.clone();
+
  // And finally render the whole crate's documentation
- cx.krate(krate)
+ let result = cx.krate(krate);
+
+ let markdown_warnings = scx.markdown_warnings.borrow();
+ if !markdown_warnings.is_empty() {
+ println!("WARNING: documentation for this crate may be rendered \
+ differently using the new Pulldown renderer.");
+ println!(" See https://github.com/rust-lang/rust/issues/44229 for details.");
+ for &(ref span, ref text, ref diffs) in &*markdown_warnings {
+ println!("WARNING: rendering difference in `{}`", concise_str(text));
+ println!(" --> {}:{}:{}", span.filename, span.loline, span.locol);
+ for d in diffs {
+ render_difference(d);
+ }
+ }
+ }
+
+ result
+}
+
+// A short, single-line view of `s`.
+fn concise_str(s: &str) -> String {
+ if s.contains('\n') {
+ return format!("{}...", s.lines().next().expect("Impossible! We just found a newline"));
+ }
+ if s.len() > 70 {
+ return format!("{} ... {}", &s[..50], &s[s.len()-20..]);
+ }
+ s.to_owned()
+}
+
+// Returns short versions of s1 and s2, starting from where the strings differ.
+fn concise_compared_strs(s1: &str, s2: &str) -> (String, String) {
+ let s1 = s1.trim();
+ let s2 = s2.trim();
+ if !s1.contains('\n') && !s2.contains('\n') && s1.len() <= 70 && s2.len() <= 70 {
+ return (s1.to_owned(), s2.to_owned());
+ }
+
+ let mut start_byte = 0;
+ for (c1, c2) in s1.chars().zip(s2.chars()) {
+ if c1 != c2 {
+ break;
+ }
+
+ start_byte += c1.len_utf8();
+ }
+
+ if start_byte == 0 {
+ return (concise_str(s1), concise_str(s2));
+ }
+
+ let s1 = &s1[start_byte..];
+ let s2 = &s2[start_byte..];
+ (format!("...{}", concise_str(s1)), format!("...{}", concise_str(s2)))
+}
+
+fn render_difference(diff: &html_diff::Difference) {
+ match *diff {
+ html_diff::Difference::NodeType { ref elem, ref opposite_elem } => {
+ println!(" {} Types differ: expected: `{}`, found: `{}`",
+ elem.path, elem.element_name, opposite_elem.element_name);
+ }
+ html_diff::Difference::NodeName { ref elem, ref opposite_elem } => {
+ println!(" {} Tags differ: expected: `{}`, found: `{}`",
+ elem.path, elem.element_name, opposite_elem.element_name);
+ }
+ html_diff::Difference::NodeAttributes { ref elem,
+ ref elem_attributes,
+ ref opposite_elem_attributes,
+ .. } => {
+ println!(" {} Attributes differ in `{}`: expected: `{:?}`, found: `{:?}`",
+ elem.path, elem.element_name, elem_attributes, opposite_elem_attributes);
+ }
+ html_diff::Difference::NodeText { ref elem, ref elem_text, ref opposite_elem_text, .. } => {
+ let (s1, s2) = concise_compared_strs(elem_text, opposite_elem_text);
+ println!(" {} Text differs:\n expected: `{}`\n found: `{}`",
+ elem.path, s1, s2);
+ }
+ html_diff::Difference::NotPresent { ref elem, ref opposite_elem } => {
+ if let Some(ref elem) = *elem {
+ println!(" {} One element is missing: expected: `{}`",
+ elem.path, elem.element_name);
+ } else if let Some(ref elem) = *opposite_elem {
+ if elem.element_name.is_empty() {
+ println!(" {} Unexpected element: `{}`",
+ elem.path, concise_str(&elem.element_content));
+ } else {
+ println!(" {} Unexpected element `{}`: found: `{}`",
+ elem.path, elem.element_name, concise_str(&elem.element_content));
+ }
+ }
+ }
+ }
 }
 
 /// Build the search index from the collected metadata
@@ -1641,47 +1739,92 @@ fn plain_summary_line(s: Option<&str>) -> String {
 fn document(w: &mut fmt::Formatter, cx: &Context, item: &clean::Item) -> fmt::Result {
  document_stability(w, cx, item)?;
  let prefix = render_assoc_const_value(item);
- document_full(w, item, cx.render_type, &prefix)?;
+ document_full(w, item, cx, &prefix)?;
  Ok(())
 }
 
-fn get_html_diff(w: &mut fmt::Formatter, md_text: &str, render_type: RenderType,
- prefix: &str) -> fmt::Result {
- let output = format!("{}", Markdown(md_text, render_type));
- let old = format!("{}", Markdown(md_text, match render_type {
- RenderType::Hoedown => RenderType::Pulldown,
- RenderType::Pulldown => RenderType::Hoedown,
- }));
- let differences = html_diff::get_differences(&output, &old);
- if !differences.is_empty() {
- println!("Differences spotted in {:?}:\n{}",
- md_text,
- differences.iter()
- .filter_map(|s| {
- match *s {
- html_diff::Difference::NodeText { ref elem_text,
- ref opposite_elem_text,
- .. }
- if elem_text.trim() == opposite_elem_text.trim() => None,
- _ => Some(format!("=> {}", s.to_string())),
- }
- })
- .collect::<Vec<String>>()
- .join("\n"));
- }
+/// Render md_text as markdown. Warns the user if there are difference in
+/// rendering between Pulldown and Hoedown.
+fn render_markdown(w: &mut fmt::Formatter,
+ md_text: &str,
+ span: Span,
+ render_type: RenderType,
+ prefix: &str,
+ scx: &SharedContext)
+ -> fmt::Result {
+ let hoedown_output = format!("{}", Markdown(md_text, RenderType::Hoedown));
+ // We only emit warnings if the user has opted-in to Pulldown rendering.
+ let output = if render_type == RenderType::Pulldown {
+ let pulldown_output = format!("{}", Markdown(md_text, RenderType::Pulldown));
+ let differences = html_diff::get_differences(&pulldown_output, &hoedown_output);
+ let differences = differences.into_iter()
+ .filter(|s| {
+ match *s {
+ html_diff::Difference::NodeText { ref elem_text,
+ ref opposite_elem_text,
+ .. }
+ if match_non_whitespace(elem_text, opposite_elem_text) => false,
+ _ => true,
+ }
+ })
+ .collect::<Vec<_>>();
+
+ if !differences.is_empty() {
+ scx.markdown_warnings.borrow_mut().push((span, md_text.to_owned(), differences));
+ }
+
+ pulldown_output
+ } else {
+ hoedown_output
+ };
+
  write!(w, "<div class='docblock'>{}{}</div>", prefix, output)
 }
 
+// Returns true iff s1 and s2 match, ignoring whitespace.
+fn match_non_whitespace(s1: &str, s2: &str) -> bool {
+ let s1 = s1.trim();
+ let s2 = s2.trim();
+ let mut cs1 = s1.chars();
+ let mut cs2 = s2.chars();
+ while let Some(c1) = cs1.next() {
+ if c1.is_whitespace() {
+ continue;
+ }
+
+ loop {
+ if let Some(c2) = cs2.next() {
+ if !c2.is_whitespace() {
+ if c1 != c2 {
+ return false;
+ }
+ break;
+ }
+ } else {
+ return false;
+ }
+ }
+ }
+
+ while let Some(c2) = cs2.next() {
+ if !c2.is_whitespace() {
+ return false;
+ }
+ }
+
+ true
+}
+
 fn document_short(w: &mut fmt::Formatter, item: &clean::Item, link: AssocItemLink,
- render_type: RenderType, prefix: &str) -> fmt::Result {
+ cx: &Context, prefix: &str) -> fmt::Result {
  if let Some(s) = item.doc_value() {
  let markdown = if s.contains('\n') {
  format!("{} [Read more]({})",
  &plain_summary_line(Some(s)), naive_assoc_href(item, link))
  } else {
  format!("{}", &plain_summary_line(Some(s)))
  };
- get_html_diff(w, &markdown, render_type, prefix)?;
+ render_markdown(w, &markdown, item.source.clone(), cx.render_type, prefix, &cx.shared)?;
  } else if !prefix.is_empty() {
  write!(w, "<div class='docblock'>{}</div>", prefix)?;
  }
@@ -1703,9 +1846,9 @@ fn render_assoc_const_value(item: &clean::Item) -> String {
 }
 
 fn document_full(w: &mut fmt::Formatter, item: &clean::Item,
- render_type: RenderType, prefix: &str) -> fmt::Result {
+ cx: &Context, prefix: &str) -> fmt::Result {
  if let Some(s) = item.doc_value() {
- get_html_diff(w, s, render_type, prefix)?;
+ render_markdown(w, s, item.source.clone(), cx.render_type, prefix, &cx.shared)?;
  } else if !prefix.is_empty() {
  write!(w, "<div class='docblock'>{}</div>", prefix)?;
  }
@@ -3104,20 +3247,20 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
  // because impls can't have a stability.
  document_stability(w, cx, it)?;
  if item.doc_value().is_some() {
- document_full(w, item, cx.render_type, &prefix)?;
+ document_full(w, item, cx, &prefix)?;
  } else {
  // In case the item isn't documented,
  // provide short documentation from the trait.
- document_short(w, it, link, cx.render_type, &prefix)?;
+ document_short(w, it, link, cx, &prefix)?;
  }
  }
  } else {
  document_stability(w, cx, item)?;
- document_full(w, item, cx.render_type, &prefix)?;
+ document_full(w, item, cx, &prefix)?;
  }
  } else {
  document_stability(w, cx, item)?;
- document_short(w, item, link, cx.render_type, &prefix)?;
+ document_short(w, item, link, cx, &prefix)?;
  }
  }
  Ok(())
@@ -3586,3 +3729,35 @@ fn test_name_sorting() {
  sorted.sort_by_key(|&s| name_key(s));
  assert_eq!(names, sorted);
 }
+
+#[cfg(test)]
+#[test]
+fn test_match_non_whitespace() {
+ assert!(match_non_whitespace("", ""));
+ assert!(match_non_whitespace(" ", ""));
+ assert!(match_non_whitespace("", " "));
+
+ assert!(match_non_whitespace("a", "a"));
+ assert!(match_non_whitespace(" a ", "a"));
+ assert!(match_non_whitespace("a", " a"));
+ assert!(match_non_whitespace("abc", "abc"));
+ assert!(match_non_whitespace("abc", " abc "));
+ assert!(match_non_whitespace("abc ", "abc"));
+ assert!(match_non_whitespace("abc xyz", "abc xyz"));
+ assert!(match_non_whitespace("abc xyz", "abc\nxyz"));
+ assert!(match_non_whitespace("abc xyz", "abcxyz"));
+ assert!(match_non_whitespace("abcxyz", "abc xyz"));
+ assert!(match_non_whitespace("abc xyz ", " abc xyz\n"));
+
+ assert!(!match_non_whitespace("a", "b"));
+ assert!(!match_non_whitespace(" a ", "c"));
+ assert!(!match_non_whitespace("a", " aa"));
+ assert!(!match_non_whitespace("abc", "ac"));
+ assert!(!match_non_whitespace("abc", " adc "));
+ assert!(!match_non_whitespace("abc ", "abca"));
+ assert!(!match_non_whitespace("abc xyz", "abc xy"));
+ assert!(!match_non_whitespace("abc xyz", "bc\nxyz"));
+ assert!(!match_non_whitespace("abc xyz", "abc.xyz"));
+ assert!(!match_non_whitespace("abcxyz", "abc.xyz"));
+ assert!(!match_non_whitespace("abc xyz ", " abc xyz w"));
+}

src/libstd/io/mod.rs

@@ -212,7 +212,7 @@
 //! # }
 //! ```
 //!
-//! [functions-list]: #functions-2
+//! [functions-list]: #functions-1
 //!
 //! ## io::Result
 //!

src/test/rustdoc/issue-29449.rs

@@ -18,12 +18,12 @@ impl Foo {
  /// # Panics
  pub fn bar() {}
 
- // @has - '//*[@id="examples-2"]//a' 'Examples'
+ // @has - '//*[@id="examples-1"]//a' 'Examples'
  /// # Examples
  pub fn bar_1() {}
 
- // @has - '//*[@id="examples-4"]//a' 'Examples'
- // @has - '//*[@id="panics-2"]//a' 'Panics'
+ // @has - '//*[@id="examples-2"]//a' 'Examples'
+ // @has - '//*[@id="panics-1"]//a' 'Panics'
  /// # Examples
  /// # Panics
  pub fn bar_2() {}