Rustdoc check option

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,

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");

src/test/rustdoc-ui/check-fail.rs

@@ -0,0 +1,21 @@
+// compile-flags: -Z unstable-options --check
+
+#![deny(missing_docs)]
+#![deny(rustdoc)]
+
+//! ```rust,testharness
+//~^ ERROR
+//! let x = 12;
+//! ```
+
+pub fn foo() {}
+//~^ ERROR
+//~^^ ERROR
+
+/// hello
+//~^ ERROR
+///
+/// ```rust,testharness
+/// let x = 12;
+/// ```
+pub fn bar() {}

src/test/rustdoc-ui/check-fail.stderr

@@ -0,0 +1,57 @@
+error: missing documentation for a function
+  --> $DIR/check-fail.rs:11:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/check-fail.rs:3:9
+   |
+LL | #![deny(missing_docs)]
+   |         ^^^^^^^^^^^^
+
+error: missing code example in this documentation
+  --> $DIR/check-fail.rs:11:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/check-fail.rs:4:9
+   |
+LL | #![deny(rustdoc)]
+   |         ^^^^^^^
+   = note: `#[deny(missing_doc_code_examples)]` implied by `#[deny(rustdoc)]`
+
+error: unknown attribute `testharness`. Did you mean `test_harness`?
+  --> $DIR/check-fail.rs:6:1
+   |
+LL | / //! ```rust,testharness
+LL | |
+LL | | //! let x = 12;
+LL | | //! ```
+   | |_______^
+   |
+note: the lint level is defined here
+  --> $DIR/check-fail.rs:4:9
+   |
+LL | #![deny(rustdoc)]
+   |         ^^^^^^^
+   = note: `#[deny(invalid_codeblock_attributes)]` implied by `#[deny(rustdoc)]`
+   = help: the code block will either not be tested if not marked as a rust one or the code will be wrapped inside a main function
+
+error: unknown attribute `testharness`. Did you mean `test_harness`?
+  --> $DIR/check-fail.rs:15:1
+   |
+LL | / /// hello
+LL | |
+LL | | ///
+LL | | /// ```rust,testharness
+LL | | /// let x = 12;
+LL | | /// ```
+   | |_______^
+   |
+   = help: the code block will either not be tested if not marked as a rust one or the code will be wrapped inside a main function
+
+error: aborting due to 4 previous errors
+

src/test/rustdoc-ui/check.rs

@@ -0,0 +1,11 @@
+// check-pass
+// compile-flags: -Z unstable-options --check
+
+#![warn(missing_docs)]
+//~^ WARN
+//~^^ WARN
+#![warn(rustdoc)]
+
+pub fn foo() {}
+//~^ WARN
+//~^^ WARN

src/test/rustdoc-ui/check.stderr

@@ -0,0 +1,49 @@
+warning: missing documentation for the crate
+  --> $DIR/check.rs:4:1
+   |
+LL | / #![warn(missing_docs)]
+LL | |
+LL | |
+LL | | #![warn(rustdoc)]
+LL | |
+LL | | pub fn foo() {}
+   | |_______________^
+   |
+note: the lint level is defined here
+  --> $DIR/check.rs:4:9
+   |
+LL | #![warn(missing_docs)]
+   |         ^^^^^^^^^^^^
+
+warning: missing documentation for a function
+  --> $DIR/check.rs:9:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^
+
+warning: missing code example in this documentation
+  --> $DIR/check.rs:4:1
+   |
+LL | / #![warn(missing_docs)]
+LL | |
+LL | |
+LL | | #![warn(rustdoc)]
+LL | |
+LL | | pub fn foo() {}
+   | |_______________^
+   |
+note: the lint level is defined here
+  --> $DIR/check.rs:7:9
+   |
+LL | #![warn(rustdoc)]
+   |         ^^^^^^^
+   = note: `#[warn(missing_doc_code_examples)]` implied by `#[warn(rustdoc)]`
+
+warning: missing code example in this documentation
+  --> $DIR/check.rs:9:1
+   |
+LL | pub fn foo() {}
+   | ^^^^^^^^^^^^^^^
+
+warning: 4 warnings emitted
+

src/test/rustdoc/check.rs

@@ -0,0 +1,5 @@
+// compile-flags: -Z unstable-options --check
+
+// @!has check/fn.foo.html
+// @!has check/index.html
+pub fn foo() {}