ff/?: really bad way of preventing Cargo.toml to not cause recompiles

Causes false negatives when Cargo.toml changed, cache lookups will still
succeed.

Author: drahnr

src/compiler/rust.rs

@@ -231,16 +231,14 @@ where
     let pool = pool.clone();
     let cwd = cwd.to_owned();
     let crate_name = crate_name.to_owned();
-    let cargo_toml = cwd.join("Cargo.toml");
-    trace!("[{}]: add cargo_toml: {:?}", crate_name, cargo_toml.display());
 
     Box::new(dep_info.and_then(move |_| -> SFuture<_> {
         let name2 = crate_name.clone();
         let parsed = pool.spawn_fn(move || {
             parse_dep_file(&dep_file, &cwd)
                 .chain_err(|| format!("Failed to parse dep info for {}", name2))
         });
-        Box::new(parsed.map(move |mut files| {
+        Box::new(parsed.map(move |files| {
             trace!(
                 "[{}]: got {} source files from dep-info in {}",
                 crate_name,
@@ -249,7 +247,6 @@ where
             );
             // Just to make sure we capture temp_dir.
             drop(temp_dir);
-            files.push(cargo_toml);
             files
         }))
     }))
@@ -1291,6 +1288,11 @@ where
             hash_all(&source_files, &source_hashes_pool)
                 .map(|source_hashes| (source_files, source_hashes))
         });
+
+        let crate_name = crate_name.to_owned();
+        let cargo_toml = cwd.join("Cargo.toml");
+        trace!("[{}]: add cargo_toml: {:?}", &crate_name, cargo_toml.display());
+
         // Hash the contents of the externs listed on the commandline.
         trace!("[{}]: hashing {} externs", crate_name, externs.len());
         let abs_externs = externs.iter().map(|e| cwd.join(e)).collect::<Vec<_>>();
@@ -1463,6 +1465,7 @@ where
                             .into_iter()
                             .chain(abs_externs)
                             .chain(abs_staticlibs)
+                            .chain(vec![cargo_toml])
                             .collect();
 
                         HashResult {
@@ -2981,8 +2984,6 @@ c:/foo/bar.rs:
         m.update(empty_digest.as_bytes());
         // libbaz.a (static library, from staticlibs)
         m.update(empty_digest.as_bytes());
-        // Cargo.toml
-        m.update(empty_digest.as_bytes());
         // Env vars
         OsStr::new("CARGO_BLAH").hash(&mut HashToDigest { digest: &mut m });
         m.update(b"=");