Allow cargo fix if gitignore matches root working dir.

src/cargo/util/vcs.rs

@@ -13,9 +13,12 @@ use crate::util::{process, CargoResult};
 pub fn existing_vcs_repo(path: &Path, cwd: &Path) -> bool {
     fn in_git_repo(path: &Path, cwd: &Path) -> bool {
         if let Ok(repo) = GitRepo::discover(path, cwd) {
-            repo.is_path_ignored(path)
+            // Don't check if the working directory itself is ignored.
-                .map(|ignored| !ignored)
+            if repo.workdir().map_or(false, |workdir| workdir == path) {
-                .unwrap_or(true)
+                true
+            } else {
+                !repo.is_path_ignored(path).unwrap_or(false)
+            }
         } else {
             false
         }

tests/testsuite/fix.rs

@@ -1289,3 +1289,26 @@ fn fix_with_common() {
 
     assert_eq!(p.read_file("tests/common/mod.rs"), "pub fn r#try() {}");
 }
+
+#[test]
+fn fix_in_existing_repo_weird_ignore() {
+    // Check that ignore doesn't ignore the repo itself.
+    let p = git::new("foo", |project| {
+        project
+            .file("src/lib.rs", "")
+            .file(".gitignore", "foo\ninner\n")
+            .file("inner/file", "")
+    })
+    .unwrap();
+
+    p.cargo("fix").run();
+    // This is questionable about whether it is the right behavior. It should
+    // probably be checking if any source file for the current project is
+    // ignored.
+    p.cargo("fix")
+        .cwd(p.root().join("inner"))
+        .with_stderr_contains("[ERROR] no VCS found[..]")
+        .with_status(101)
+        .run();
+    p.cargo("fix").cwd(p.root().join("src")).run();
+}