From a51b13042e48c40a87597496fac01dc605aca55d Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Thu, 12 Nov 2020 14:57:44 +0100
Subject: [PATCH] Add --check option to rustdoc

---
 src/librustdoc/config.rs | 6 ++++++
 src/librustdoc/lib.rs    | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index 02885f51936..c248d57a9dd 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -145,6 +145,9 @@ pub struct Options {
     pub render_options: RenderOptions,
     /// Output format rendering (used only for "show-coverage" option for the moment)
     pub output_format: Option<OutputFormat>,
+    /// If this option is set to `true`, rustdoc will only run checks and not generate
+    /// documentation.
+    pub run_check: bool,
 }
 
 impl fmt::Debug for Options {
@@ -185,6 +188,7 @@ impl fmt::Debug for Options {
             .field("runtool", &self.runtool)
             .field("runtool_args", &self.runtool_args)
             .field("enable-per-target-ignores", &self.enable_per_target_ignores)
+            .field("run_check", &self.run_check)
             .finish()
     }
 }
@@ -581,6 +585,7 @@ impl Options {
         let enable_per_target_ignores = matches.opt_present("enable-per-target-ignores");
         let document_private = matches.opt_present("document-private-items");
         let document_hidden = matches.opt_present("document-hidden-items");
+        let run_check = matches.opt_present("check");
 
         let (lint_opts, describe_lints, lint_cap) = get_cmd_lint_options(matches, error_format);
 
@@ -616,6 +621,7 @@ impl Options {
             runtool_args,
             enable_per_target_ignores,
             test_builder,
+            run_check,
             render_options: RenderOptions {
                 output,
                 external_html,
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 7efbca5c6c3..d23c722e78e 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -423,6 +423,7 @@ fn opts() -> Vec<RustcOptGroup> {
                 "specified the rustc-like binary to use as the test builder",
             )
         }),
+        unstable("check", |o| o.optflag("", "check", "Run rustdoc checks")),
     ]
 }
 
@@ -514,6 +515,7 @@ fn main_options(options: config::Options) -> MainResult {
     // but we can't crates the Handler ahead of time because it's not Send
     let diag_opts = (options.error_format, options.edition, options.debugging_opts.clone());
     let show_coverage = options.show_coverage;
+    let run_check = options.run_check;
 
     // First, parse the crate and extract all relevant information.
     info!("starting to run rustc");
@@ -539,6 +541,9 @@ fn main_options(options: config::Options) -> MainResult {
         // if we ran coverage, bail early, we don't need to also generate docs at this point
         // (also we didn't load in any of the useful passes)
         return Ok(());
+    } else if run_check {
+        // Since we're in "check" mode, no need to generate anything beyond this point.
+        return Ok(());
     }
 
     info!("going to format");