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Remove hoedown from rustdoc

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Is it really time? Have our months, no, *years* of suffering come to an end? Are we finally able to cast off the pall of Hoedown? The weight which has dragged us down for so long?

-----

So, timeline for those who need to catch up:

* Way back in December 2016, [we decided we wanted to switch out the markdown renderer](https://github.com/rust-lang/rust/issues/38400). However, this was put on hold because the build system at the time made it difficult to pull in dependencies from crates.io.
* A few months later, in March 2017, [the first PR was done, to switch out the renderers entirely](https://github.com/rust-lang/rust/pull/40338). The PR itself was fraught with CI and build system issues, but eventually landed.
* However, not all was well in the Rustdoc world. During the PR and shortly after, we noticed [some differences in the way the two parsers handled some things](https://github.com/rust-lang/rust/issues/40912), and some of these differences were major enough to break the docs for some crates.
* A couple weeks afterward, [Hoedown was put back in](https://github.com/rust-lang/rust/pull/41290), at this point just to catch tests that Pulldown was "spuriously" running. This would at least provide some warning about spurious tests, rather than just breaking spontaneously.
* However, the problems had created enough noise by this point that just a few days after that, [Hoedown was switched back to the default](https://github.com/rust-lang/rust/pull/41431) while we came up with a solution for properly warning about the differences.
* That solution came a few weeks later, [as a series of warnings when the HTML emitted by the two parsers was semantically different](https://github.com/rust-lang/rust/pull/41991). But that came at a cost, as now rustdoc needed proc-macro support (the new crate needed some custom derives farther down its dependency tree), and the build system was not equipped to handle it at the time. It was worked on for three months as the issue stumped more and more people.
  * In that time, [bootstrap was completely reworked](https://github.com/rust-lang/rust/pull/43059) to change how it ordered compilation, and [the method by which it built rustdoc would change](https://github.com/rust-lang/rust/pull/43482), as well. This allowed it to only be built after stage1, when proc-macros would be available, allowing the "rendering differences" PR to finally land.
  * The warnings were not perfect, and revealed a few [spurious](https://github.com/rust-lang/rust/pull/44368) [differences](https://github.com/rust-lang/rust/pull/45421) between how we handled the renderers.
  * Once these were handled, [we flipped the switch to turn on the "rendering difference" warnings all the time](https://github.com/rust-lang/rust/pull/45324), in October 2017. This began the "warning cycle" for this change, and landed in stable in 1.23, on 2018-01-04.
  * Once those warnings hit stable, and after a couple weeks of seeing whether we would get any more reports than what we got from sitting on nightly/beta, [we switched the renderers](https://github.com/rust-lang/rust/pull/47398), making Pulldown the default but still offering the option to use Hoedown.

And that brings us to the present. We haven't received more new issues from this in the meantime, and the "switch by default" is now on beta. Our reasoning is that, at this point, anyone who would have been affected by this has run into it already.
This commit is contained in:
Guillaume Gomez
2018-02-16 15:09:19 +01:00
parent 5570cdcc9e
commit 5bd5bc3f21
18 changed files with 110 additions and 1370 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
src/librustdoc/markdown.rs
View File

@@ -17,20 +17,14 @@ use getopts;
use testing;
use rustc::session::search_paths::SearchPaths;
use rustc::session::config::Externs;
use syntax::codemap::{DUMMY_SP, FileName};
use clean::Span;
use syntax::codemap::DUMMY_SP;
use externalfiles::{ExternalHtml, LoadStringError, load_string};
use html_diff;
use html::render::{render_text, reset_ids};
use html::render::reset_ids;
use html::escape::Escape;
use html::render::render_difference;
use html::markdown;
use html::markdown::{Markdown, MarkdownWithToc, find_testable_code, old_find_testable_code};
use html::markdown::RenderType;
use html::markdown::{Markdown, MarkdownWithToc, find_testable_code};
use test::{TestOptions, Collector};
/// Separate any lines at the start of the file that begin with `# ` or `%`.
@@ -55,12 +49,7 @@ fn extract_leading_metadata<'a>(s: &'a str) -> (Vec<&'a str>, &'a str) {
/// Render `input` (e.g. "foo.md") into an HTML file in `output`
/// (e.g. output = "bar" => "bar/foo.html").
pub fn render(input: &Path, mut output: PathBuf, matches: &getopts::Matches,
external_html: &ExternalHtml, include_toc: bool,
render_type: RenderType) -> isize {
// Span used for markdown hoedown/pulldown differences.
let mut span = Span::empty();
span.filename = FileName::Real(input.to_owned());
external_html: &ExternalHtml, include_toc: bool) -> isize {
output.push(input.file_stem().unwrap());
output.set_extension("html");
@@ -97,36 +86,12 @@ pub fn render(input: &Path, mut output: PathBuf, matches: &getopts::Matches,
reset_ids(false);
let (hoedown_output, pulldown_output) = if include_toc {
// Save the state of USED_ID_MAP so it only gets updated once even
// though we're rendering twice.
render_text(|ty| format!("{}", MarkdownWithToc(text, ty)))
let text = if include_toc {
format!("{}", MarkdownWithToc(text))
} else {
// Save the state of USED_ID_MAP so it only gets updated once even
// though we're rendering twice.
render_text(|ty| format!("{}", Markdown(text, &[], ty)))
format!("{}", Markdown(text, &[]))
};
let mut differences = html_diff::get_differences(&pulldown_output, &hoedown_output);
differences.retain(|s| {
match *s {
html_diff::Difference::NodeText { ref elem_text,
ref opposite_elem_text,
.. }
if elem_text.split_whitespace().eq(opposite_elem_text.split_whitespace()) => {
false
}
_ => true,
}
});
if !differences.is_empty() {
let mut intro_msg = false;
for diff in differences {
render_difference(&diff, &mut intro_msg, &span, text);
}
}
let err = write!(
&mut out,
r#"<!DOCTYPE html>
@@ -158,7 +123,7 @@ pub fn render(input: &Path, mut output: PathBuf, matches: &getopts::Matches,
css = css,
in_header = external_html.in_header,
before_content = external_html.before_content,
text = if render_type == RenderType::Pulldown { pulldown_output } else { hoedown_output },
text = text,
after_content = external_html.after_content,
);
@@ -174,7 +139,7 @@ pub fn render(input: &Path, mut output: PathBuf, matches: &getopts::Matches,
/// Run any tests/code examples in the markdown file `input`.
pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
mut test_args: Vec<String>, maybe_sysroot: Option<PathBuf>,
render_type: RenderType, display_warnings: bool, linker: Option<PathBuf>) -> isize {
display_warnings: bool, linker: Option<PathBuf>) -> isize {
let input_str = match load_string(input) {
Ok(s) => s,
Err(LoadStringError::ReadFail) => return 1,
@@ -186,13 +151,8 @@ pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
let mut collector = Collector::new(input.to_owned(), cfgs, libs, externs,
true, opts, maybe_sysroot, None,
Some(PathBuf::from(input)),
render_type, linker);
if render_type == RenderType::Pulldown {
old_find_testable_code(&input_str, &mut collector, DUMMY_SP);
find_testable_code(&input_str, &mut collector, DUMMY_SP);
} else {
old_find_testable_code(&input_str, &mut collector, DUMMY_SP);
}
linker);
find_testable_code(&input_str, &mut collector, DUMMY_SP);
test_args.insert(0, "rustdoctest".to_string());
testing::test_main(&test_args, collector.tests,
testing::Options::new().display_output(display_warnings));