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Auto merge of rust-lang#57019 - QuietMisdreavus:semi-revert-doctest-p…
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…arsing, r=GuillaumeGomez

[beta] rustdoc: semi-revert libsyntax doctest parsing if a macro is wrapping main

Fixes rust-lang#56898

This is a patch to doctest parsing on beta (that i plan to "forward-port" to master) that reverts to the old text-based `fn main` scan if it found a macro invocation in the doctest but did not find a main function. This should solve situations like `allocator_api` which wrap their main functions in a macro invocation, but doesn't solve something like the initial version of `quicli` which used a macro to *generate* the main function. (Properly doing the latter involves running macro expansion before checking, which is a bit too involved for a beta fix.)
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bors committed Jan 5, 2019
2 parents e64fee6 + 339148d commit 2bde39b
Showing 1 changed file with 48 additions and 3 deletions.
51 changes: 48 additions & 3 deletions src/librustdoc/test.rs
Original file line number Diff line number Diff line change
Expand Up @@ -395,7 +395,7 @@ pub fn make_test(s: &str,

// Uses libsyntax to parse the doctest and find if there's a main fn and the extern
// crate already is included.
let (already_has_main, already_has_extern_crate) = crate::syntax::with_globals(|| {
let (already_has_main, already_has_extern_crate, found_macro) = crate::syntax::with_globals(|| {
use crate::syntax::{ast, parse::{self, ParseSess}, source_map::FilePathMapping};
use crate::syntax_pos::FileName;
use errors::emitter::EmitterWriter;
Expand All @@ -415,6 +415,7 @@ pub fn make_test(s: &str,

let mut found_main = false;
let mut found_extern_crate = cratename.is_none();
let mut found_macro = false;

let mut parser = match parse::maybe_new_parser_from_source_str(&sess, filename, source) {
Ok(p) => p,
Expand All @@ -423,7 +424,7 @@ pub fn make_test(s: &str,
err.cancel();
}

return (found_main, found_extern_crate);
return (found_main, found_extern_crate, found_macro);
}
};

Expand Down Expand Up @@ -451,6 +452,12 @@ pub fn make_test(s: &str,
}
}

if !found_macro {
if let ast::ItemKind::Mac(..) = item.node {
found_macro = true;
}
}

if found_main && found_extern_crate {
break;
}
Expand All @@ -463,9 +470,28 @@ pub fn make_test(s: &str,
}
}

(found_main, found_extern_crate)
(found_main, found_extern_crate, found_macro)
});

// If a doctest's `fn main` is being masked by a wrapper macro, the parsing loop above won't
// see it. In that case, run the old text-based scan to see if they at least have a main
// function written inside a macro invocation. See
// https://github.com/rust-lang/rust/issues/56898
let already_has_main = if found_macro && !already_has_main {
s.lines()
.map(|line| {
let comment = line.find("//");
if let Some(comment_begins) = comment {
&line[0..comment_begins]
} else {
line
}
})
.any(|code| code.contains("fn main"))
} else {
already_has_main
};

// Don't inject `extern crate std` because it's already injected by the
// compiler.
if !already_has_extern_crate && !opts.no_crate_inject && cratename != Some("std") {
Expand Down Expand Up @@ -1106,4 +1132,23 @@ assert_eq!(asdf::foo, 4);
let output = make_test(input, Some("asdf"), false, &opts);
assert_eq!(output, (expected, 3));
}

#[test]
fn make_test_main_in_macro() {
let opts = TestOptions::default();
let input =
"#[macro_use] extern crate my_crate;
test_wrapper! {
fn main() {}
}";
let expected =
"#![allow(unused)]
#[macro_use] extern crate my_crate;
test_wrapper! {
fn main() {}
}".to_string();

let output = make_test(input, Some("my_crate"), false, &opts);
assert_eq!(output, (expected, 1));
}
}

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