From 77855f36362df3e1697ae4b9e39262c9d271d230 Mon Sep 17 00:00:00 2001
From: Eric Huss <eric@huss.org>
Date: Mon, 26 Apr 2021 21:02:29 -0700
Subject: [PATCH 1/2] Use consolidated fingerprint directory for rustdoc.

---
 .../compiler/context/compilation_files.rs     |  2 +-
 tests/testsuite/doc.rs                        | 36 ++++++++++++++++++-
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/src/cargo/core/compiler/context/compilation_files.rs b/src/cargo/core/compiler/context/compilation_files.rs
index 37b11da8471..026b95e8d04 100644
--- a/src/cargo/core/compiler/context/compilation_files.rs
+++ b/src/cargo/core/compiler/context/compilation_files.rs
@@ -598,7 +598,7 @@ fn hash_rustc_version(bcx: &BuildContext<'_, '_>, hasher: &mut StableHasher) {
 
 /// Returns whether or not this unit should use a metadata hash.
 fn should_use_metadata(bcx: &BuildContext<'_, '_>, unit: &Unit) -> bool {
-    if unit.mode.is_doc_test() {
+    if unit.mode.is_doc_test() || unit.mode.is_doc() {
         // Doc tests do not have metadata.
         return false;
     }
diff --git a/tests/testsuite/doc.rs b/tests/testsuite/doc.rs
index e03b5a18513..7cd3d0d0381 100644
--- a/tests/testsuite/doc.rs
+++ b/tests/testsuite/doc.rs
@@ -863,10 +863,44 @@ fn features() {
             r#"#[cfg(feature = "bar")] pub fn bar() {}"#,
         )
         .build();
-    p.cargo("doc --features foo").run();
+    p.cargo("doc --features foo")
+        .with_stderr(
+            "\
+[COMPILING] bar v0.0.1 [..]
+[DOCUMENTING] bar v0.0.1 [..]
+[DOCUMENTING] foo v0.0.1 [..]
+[FINISHED] [..]
+",
+        )
+        .run();
     assert!(p.root().join("target/doc").is_dir());
     assert!(p.root().join("target/doc/foo/fn.foo.html").is_file());
     assert!(p.root().join("target/doc/bar/fn.bar.html").is_file());
+    // Check that turning the feature off will remove the files.
+    p.cargo("doc")
+        .with_stderr(
+            "\
+[COMPILING] bar v0.0.1 [..]
+[DOCUMENTING] bar v0.0.1 [..]
+[DOCUMENTING] foo v0.0.1 [..]
+[FINISHED] [..]
+",
+        )
+        .run();
+    // assert!(!p.root().join("target/doc/foo/fn.foo.html").is_file());
+    // assert!(!p.root().join("target/doc/bar/fn.bar.html").is_file());
+    // And switching back will rebuild and bring them back.
+    p.cargo("doc --features foo")
+        .with_stderr(
+            "\
+[DOCUMENTING] bar v0.0.1 [..]
+[DOCUMENTING] foo v0.0.1 [..]
+[FINISHED] [..]
+",
+        )
+        .run();
+    assert!(p.root().join("target/doc/foo/fn.foo.html").is_file());
+    assert!(p.root().join("target/doc/bar/fn.bar.html").is_file());
 }
 
 #[cargo_test]

From 44c549e6505c418a0c41360a5edd6edf008fda40 Mon Sep 17 00:00:00 2001
From: Eric Huss <eric@huss.org>
Date: Mon, 26 Apr 2021 21:04:01 -0700
Subject: [PATCH 2/2] Clear rustdoc output just before running rustdoc.

---
 src/cargo/core/compiler/mod.rs | 12 ++++++++++--
 tests/testsuite/doc.rs         |  4 ++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/cargo/core/compiler/mod.rs b/src/cargo/core/compiler/mod.rs
index 0551f7ce5ed..eadfb83db2a 100644
--- a/src/cargo/core/compiler/mod.rs
+++ b/src/cargo/core/compiler/mod.rs
@@ -594,7 +594,8 @@ fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
     // script_metadata is not needed here, it is only for tests.
     let mut rustdoc = cx.compilation.rustdoc_process(unit, None)?;
     rustdoc.inherit_jobserver(&cx.jobserver);
-    rustdoc.arg("--crate-name").arg(&unit.target.crate_name());
+    let crate_name = unit.target.crate_name();
+    rustdoc.arg("--crate-name").arg(&crate_name);
     add_path_args(bcx.ws, unit, &mut rustdoc);
     add_cap_lints(bcx, unit, &mut rustdoc);
 
@@ -608,7 +609,7 @@ fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
     // it doesn't already exist.
     paths::create_dir_all(&doc_dir)?;
 
-    rustdoc.arg("-o").arg(doc_dir);
+    rustdoc.arg("-o").arg(&doc_dir);
 
     for feat in &unit.features {
         rustdoc.arg("--cfg").arg(&format!("feature=\"{}\"", feat));
@@ -648,6 +649,13 @@ fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
                 }
             }
         }
+        let crate_dir = doc_dir.join(&crate_name);
+        if crate_dir.exists() {
+            // Remove output from a previous build. This ensures that stale
+            // files for removed items are removed.
+            log::debug!("removing pre-existing doc directory {:?}", crate_dir);
+            paths::remove_dir_all(crate_dir)?;
+        }
         state.running(&rustdoc);
 
         rustdoc
diff --git a/tests/testsuite/doc.rs b/tests/testsuite/doc.rs
index 7cd3d0d0381..01b25612e5b 100644
--- a/tests/testsuite/doc.rs
+++ b/tests/testsuite/doc.rs
@@ -887,8 +887,8 @@ fn features() {
 ",
         )
         .run();
-    // assert!(!p.root().join("target/doc/foo/fn.foo.html").is_file());
-    // assert!(!p.root().join("target/doc/bar/fn.bar.html").is_file());
+    assert!(!p.root().join("target/doc/foo/fn.foo.html").is_file());
+    assert!(!p.root().join("target/doc/bar/fn.bar.html").is_file());
     // And switching back will rebuild and bring them back.
     p.cargo("doc --features foo")
         .with_stderr(