fix: create ephemeral workspace for git source

src/cargo/core/workspace.rs

@@ -283,6 +283,10 @@ impl<'gctx> Workspace<'gctx> {
         ws.member_ids.insert(id);
         ws.default_members.push(ws.current_manifest.clone());
         ws.set_resolve_behavior();
+        // The find_root function is used here to traverse the directory tree and locate the root of the workspace.
+        // Despite being ephemeral, we still need to validate all the manifests in the workspace,
+        // which is what `find_root` helps us achieve here.
+        ws.find_root(ws.current_manifest.clone().as_path())?;
         Ok(ws)
     }
 

src/cargo/ops/cargo_install.rs

@@ -816,7 +816,7 @@ fn make_ws_rustc_target<'gctx>(
     source_id: &SourceId,
     pkg: Package,
 ) -> CargoResult<(Workspace<'gctx>, Rustc, String)> {
-    let mut ws = if source_id.is_git() || source_id.is_path() {
+    let mut ws = if source_id.is_path() {
         Workspace::new(pkg.manifest_path(), gctx)?
     } else {
         Workspace::ephemeral(pkg, gctx, None, false)?

tests/testsuite/install.rs

@@ -2124,6 +2124,7 @@ fn git_install_the_same_bin_twice_with_different_rev() {
         "\
 [UPDATING] git repository [..]
 [INSTALLING] bin1 v0.1.0 [..]
+[COMPILING] bin1 v0.1.0 [..]
 [FINISHED] [..]
 [REPLACING] [..]home/.cargo/bin/bin1[..]
 [REPLACED] package `bin1 [..]