Make target dir self-ignoring

Author: senekor

src/cargo/core/workspace.rs

@@ -402,9 +402,16 @@ impl<'gctx> Workspace<'gctx> {
     }
 
     pub fn target_dir(&self) -> Filesystem {
-        self.target_dir
+        let target_dir = self
+            .target_dir
             .clone()
-            .unwrap_or_else(|| self.default_target_dir())
+            .unwrap_or_else(|| self.default_target_dir());
+
+        let path = target_dir.as_path_unlocked();
+        paths::create_dir_all(path).unwrap();
+        std::fs::write(path.join(".gitignore"), "*\n").unwrap();
+
+        target_dir
     }
 
     fn default_target_dir(&self) -> Filesystem {

src/cargo/ops/cargo_new.rs

@@ -680,7 +680,7 @@ fn write_ignore_file(base_path: &Path, list: &IgnoreList, vcs: VersionControl) -
     }
 
     for fp_ignore in match vcs {
-        VersionControl::Git => vec![base_path.join(".gitignore")],
+        VersionControl::Git => return Ok(()), // target-dir already contains wildcard gitignore file
         VersionControl::Hg => vec![base_path.join(".hgignore")],
         VersionControl::Pijul => vec![base_path.join(".ignore")],
         // Fossil has a cleaning functionality configured in a separate file.

tests/testsuite/cargo_init/auto_git/out/.gitignore

@@ -1,5 +1 @@
-**/some.file
-
-# Added by cargo
-
-/target
+**/some.file

tests/testsuite/cargo_init/explicit_bin_with_git/out/.gitignore

@@ -1,8 +1,2 @@
 /target
-**/some.file
-
-# Added by cargo
-#
-# already existing elements were commented out
-
-#/target
+**/some.file