Don't print rustdoc command lines on failure by default

This commit lifts a helper function from invoking rustc to additionally
being used for invoking rustdoc. This enables hiding the command line
invocation of `rustdoc` by default when it fails, although it's still
available to see with `--verbose`. The intention here is to match the
behavior of `cargo build` for rustc failures here and was inspired by
recently running `cargo doc` and not being able to see the actual
failure as the command line ended up taking the whole screen (afterwards
I made the screen bigger and that helped too).

src/cargo/core/compiler/mod.rs

@@ -376,19 +376,6 @@ fn rustc(cx: &mut Context<'_, '_>, unit: &Unit, exec: &Arc<dyn Executor>) -> Car
             }
         }
 
-        fn verbose_if_simple_exit_code(err: Error) -> Error {
-            // If a signal on unix (`code == None`) or an abnormal termination
-            // on Windows (codes like `0xC0000409`), don't hide the error details.
-            match err
-                .downcast_ref::<ProcessError>()
-                .as_ref()
-                .and_then(|perr| perr.code)
-            {
-                Some(n) if cargo_util::is_simple_exit_code(n) => VerboseError::new(err).into(),
-                _ => err,
-            }
-        }
-
         state.running(&rustc);
         let timestamp = paths::set_invocation_time(&fingerprint_dir)?;
         if build_plan {
@@ -510,6 +497,19 @@ fn rustc(cx: &mut Context<'_, '_>, unit: &Unit, exec: &Arc<dyn Executor>) -> Car
     }
 }
 
+fn verbose_if_simple_exit_code(err: Error) -> Error {
+    // If a signal on unix (`code == None`) or an abnormal termination
+    // on Windows (codes like `0xC0000409`), don't hide the error details.
+    match err
+        .downcast_ref::<ProcessError>()
+        .as_ref()
+        .and_then(|perr| perr.code)
+    {
+        Some(n) if cargo_util::is_simple_exit_code(n) => VerboseError::new(err).into(),
+        _ => err,
+    }
+}
+
 /// Link the compiled target (often of form `foo-{metadata_hash}`) to the
 /// final target. This must happen during both "Fresh" and "Compile".
 fn link_targets(cx: &mut Context<'_, '_>, unit: &Unit, fresh: bool) -> CargoResult<Work> {
@@ -862,6 +862,7 @@ fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
                 },
                 false,
             )
+            .map_err(verbose_if_simple_exit_code)
             .with_context(|| format!("could not document `{}`", name));
 
         if let Err(e) = result {

tests/testsuite/doc.rs

@@ -2640,3 +2640,24 @@ fn link_to_private_item() {
         )
         .run();
 }
+
+#[cargo_test]
+fn rustdoc_failure_hides_command_line_by_default() {
+    let p = project().file("src/lib.rs", "invalid rust code").build();
+
+    let string_to_test = "\
+Caused by:
+  process didn't exit successfully[..]rustdoc[..]";
+
+    // `cargo doc` doesn't print the full command line on failures by default
+    p.cargo("doc")
+        .with_stderr_does_not_contain(string_to_test)
+        .with_status(101)
+        .run();
+
+    // ... but it still does so if requested with `--verbose`.
+    p.cargo("doc --verbose")
+        .with_stderr_contains(string_to_test)
+        .with_status(101)
+        .run();
+}