Exclude whole target/ from backups

This is following the discussion on GitHub. The doc tests are no longer
necessary because Layout::new() creates CACHEDIR.TAG directly in target
root, no doc-specific code is necessary anymore.

Author: jstasiak

src/cargo/core/compiler/layout.rs

@@ -151,7 +151,10 @@ impl Layout {
         // here. Use this opportunity to exclude it from backups as well if the
         // system supports it since this is a freshly created folder.
         //
-        paths::create_dir_all_excluded_from_backups_atomic(dest.as_path_unlocked())?;
+        paths::create_dir_all_excluded_from_backups_atomic(root.as_path_unlocked())?;
+        // Now that the excluded from backups target root is created we can create the
+        // actual destination (sub)subdirectory.
+        paths::create_dir_all(dest.as_path_unlocked())?;
 
         // For now we don't do any more finer-grained locking on the artifact
         // directory, so just lock the entire thing for the duration of this

src/cargo/core/compiler/mod.rs

@@ -557,7 +557,7 @@ fn rustdoc(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Work> {
     // Create the documentation directory ahead of time as rustdoc currently has
     // a bug where concurrent invocations will race to create this directory if
     // it doesn't already exist.
-    paths::create_dir_all_excluded_from_backups_atomic(&doc_dir)?;
+    paths::create_dir_all(&doc_dir)?;
 
     rustdoc.arg("-o").arg(doc_dir);
 

tests/testsuite/build.rs

@@ -4998,7 +4998,7 @@ fn target_directory_is_excluded_from_backups() {
         .build();
 
     p.cargo("build").run();
-    let cachedir_tag = p.target_debug_dir().join("CACHEDIR.TAG");
+    let cachedir_tag = p.build_dir().join("CACHEDIR.TAG");
     assert!(cachedir_tag.is_file());
     assert!(fs::read_to_string(&cachedir_tag)
         .unwrap()
@@ -5012,7 +5012,7 @@ fn target_directory_is_not_excluded_from_backups_if_it_already_exists() {
         .file("src/foo.rs", &main_file(r#""i am foo""#, &[]))
         .build();
 
-    let cachedir_tag = p.target_debug_dir().join("CACHEDIR.TAG");
+    let cachedir_tag = p.build_dir().join("CACHEDIR.TAG");
     p.cargo("build").run();
     fs::remove_file(&cachedir_tag).unwrap();
     p.cargo("build").run();

tests/testsuite/clean.rs

@@ -293,7 +293,6 @@ fn clean_verbose() {
 [REMOVING] [..]
 [REMOVING] [..]
 [REMOVING] [..]
-[REMOVING] [..]
 ",
         )
         .run();
@@ -433,7 +432,9 @@ fn assert_all_clean(build_dir: &Path) {
     }) {
         let entry = entry.unwrap();
         let path = entry.path();
-        if let ".rustc_info.json" | ".cargo-lock" = path.file_name().unwrap().to_str().unwrap() {
+        if let ".rustc_info.json" | ".cargo-lock" | "CACHEDIR.TAG" =
+            path.file_name().unwrap().to_str().unwrap()
+        {
             continue;
         }
         if path.is_symlink() || path.is_file() {

tests/testsuite/doc.rs

@@ -1551,67 +1551,3 @@ fn crate_versions_flag_is_overridden() {
         .run();
     asserts(output_documentation());
 }
-
-#[cargo_test]
-fn target_directory_is_excluded_from_backups() {
-    let p = project()
-        .file(
-            "Cargo.toml",
-            r#"
-            [package]
-            name = "foo"
-            version = "0.0.1"
-            authors = []
-            build = "build.rs"
-        "#,
-        )
-        .file("build.rs", "fn main() {}")
-        .file("src/lib.rs", "pub fn foo() {}")
-        .build();
-
-    p.cargo("doc")
-        .with_stderr(
-            "\
-[..] foo v0.0.1 ([CWD])
-[..] foo v0.0.1 ([CWD])
-[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
-",
-        )
-        .run();
-    let cachedir_tag = p.root().join("target/doc/CACHEDIR.TAG");
-    assert!(cachedir_tag.is_file());
-    assert!(fs::read_to_string(&cachedir_tag)
-        .unwrap()
-        .starts_with("Signature: 8a477f597d28d172789f06886806bc55"));
-}
-
-#[cargo_test]
-fn target_directory_is_not_excluded_from_backups_if_it_already_exists() {
-    let p = project()
-        .file(
-            "Cargo.toml",
-            r#"
-            [package]
-            name = "foo"
-            version = "0.0.1"
-            authors = []
-            build = "build.rs"
-        "#,
-        )
-        .file("build.rs", "fn main() {}")
-        .file("src/lib.rs", "pub fn foo() {}")
-        .build();
-    fs::create_dir_all(p.root().join("target/doc")).unwrap();
-
-    p.cargo("doc")
-        .with_stderr(
-            "\
-[..] foo v0.0.1 ([CWD])
-[..] foo v0.0.1 ([CWD])
-[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
-",
-        )
-        .run();
-    let cachedir_tag = p.root().join("target/doc/CACHEDIR.TAG");
-    assert!(!&cachedir_tag.is_file());
-}