fix(embedded): Don't pollute script dir with lockfile

src/cargo/core/workspace.rs

@@ -1599,7 +1599,8 @@ impl MaybePackage {
         }
     }
 
-    fn is_embedded(&self) -> bool {
+    /// Has an embedded manifest (single-file package)
+    pub fn is_embedded(&self) -> bool {
         match self {
             MaybePackage::Package(p) => p.manifest().is_embedded(),
             MaybePackage::Virtual(_) => false,

src/cargo/ops/lockfile.rs

@@ -8,12 +8,12 @@ use crate::util::Filesystem;
 use anyhow::Context as _;
 
 pub fn load_pkg_lockfile(ws: &Workspace<'_>) -> CargoResult<Option<Resolve>> {
-    if !ws.root().join("Cargo.lock").exists() {
+    let lock_root = lock_root(ws);
+    if !lock_root.as_path_unlocked().join("Cargo.lock").exists() {
         return Ok(None);
     }
 
-    let root = Filesystem::new(ws.root().to_path_buf());
-    let mut f = root.open_ro("Cargo.lock", ws.config(), "Cargo.lock file")?;
+    let mut f = lock_root.open_ro("Cargo.lock", ws.config(), "Cargo.lock file")?;
 
     let mut s = String::new();
     f.read_to_string(&mut s)
@@ -30,12 +30,12 @@ pub fn load_pkg_lockfile(ws: &Workspace<'_>) -> CargoResult<Option<Resolve>> {
 
 /// Generate a toml String of Cargo.lock from a Resolve.
 pub fn resolve_to_string(ws: &Workspace<'_>, resolve: &mut Resolve) -> CargoResult<String> {
-    let (_orig, out, _ws_root) = resolve_to_string_orig(ws, resolve);
+    let (_orig, out, _lock_root) = resolve_to_string_orig(ws, resolve);
     Ok(out)
 }
 
 pub fn write_pkg_lockfile(ws: &Workspace<'_>, resolve: &mut Resolve) -> CargoResult<()> {
-    let (orig, mut out, ws_root) = resolve_to_string_orig(ws, resolve);
+    let (orig, mut out, lock_root) = resolve_to_string_orig(ws, resolve);
 
     // If the lock file contents haven't changed so don't rewrite it. This is
     // helpful on read-only filesystems.
@@ -55,7 +55,7 @@ pub fn write_pkg_lockfile(ws: &Workspace<'_>, resolve: &mut Resolve) -> CargoRes
             "the lock file {} needs to be updated but {} was passed to prevent this\n\
              If you want to try to generate the lock file without accessing the network, \
              remove the {} flag and use --offline instead.",
-            ws.root().to_path_buf().join("Cargo.lock").display(),
+            lock_root.as_path_unlocked().join("Cargo.lock").display(),
             flag,
             flag
         );
@@ -80,14 +80,19 @@ pub fn write_pkg_lockfile(ws: &Workspace<'_>, resolve: &mut Resolve) -> CargoRes
     }
 
     // Ok, if that didn't work just write it out
-    ws_root
+    lock_root
         .open_rw("Cargo.lock", ws.config(), "Cargo.lock file")
         .and_then(|mut f| {
             f.file().set_len(0)?;
             f.write_all(out.as_bytes())?;
             Ok(())
         })
-        .with_context(|| format!("failed to write {}", ws.root().join("Cargo.lock").display()))?;
+        .with_context(|| {
+            format!(
+                "failed to write {}",
+                lock_root.as_path_unlocked().join("Cargo.lock").display()
+            )
+        })?;
     Ok(())
 }
 
@@ -96,15 +101,15 @@ fn resolve_to_string_orig(
     resolve: &mut Resolve,
 ) -> (Option<String>, String, Filesystem) {
     // Load the original lock file if it exists.
-    let ws_root = Filesystem::new(ws.root().to_path_buf());
-    let orig = ws_root.open_ro("Cargo.lock", ws.config(), "Cargo.lock file");
+    let lock_root = lock_root(ws);
+    let orig = lock_root.open_ro("Cargo.lock", ws.config(), "Cargo.lock file");
     let orig = orig.and_then(|mut f| {
         let mut s = String::new();
         f.read_to_string(&mut s)?;
         Ok(s)
     });
     let out = serialize_resolve(resolve, orig.as_deref().ok());
-    (orig.ok(), out, ws_root)
+    (orig.ok(), out, lock_root)
 }
 
 fn serialize_resolve(resolve: &Resolve, orig: Option<&str>) -> String {
@@ -235,3 +240,11 @@ fn emit_package(dep: &toml::Table, out: &mut String) {
         out.push_str(&format!("replace = {}\n\n", &dep["replace"]));
     }
 }
+
+fn lock_root(ws: &Workspace<'_>) -> Filesystem {
+    if ws.root_maybe().is_embedded() {
+        ws.target_dir()
+    } else {
+        Filesystem::new(ws.root().to_owned())
+    }
+}

tests/testsuite/script.rs

@@ -591,3 +591,33 @@ args: []
         )
         .run();
 }
+
+#[cargo_test]
+fn no_local_lockfile() {
+    let script = ECHO_SCRIPT;
+    let p = cargo_test_support::project()
+        .file("script.rs", script)
+        .build();
+    let local_lockfile_path = p.root().join("Cargo.lock");
+
+    assert!(!local_lockfile_path.exists());
+
+    p.cargo("-Zscript script.rs")
+        .masquerade_as_nightly_cargo(&["script"])
+        .with_stdout(
+            r#"bin: [ROOT]/home/.cargo/target/[..]/debug/script[EXE]
+args: []
+"#,
+        )
+        .with_stderr(
+            "\
+[WARNING] `package.edition` is unspecifiead, defaulting to `2021`
+[COMPILING] script v0.0.0 ([ROOT]/foo)
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]s
+[RUNNING] `[ROOT]/home/.cargo/target/[..]/debug/script[EXE]`
+",
+        )
+        .run();
+
+    assert!(!local_lockfile_path.exists());
+}