Use a hash for -C metadata instead of a string

This ends up serving the same purpose, but a critical change is that it
canonicalizes the relevant git url (if one is used) to ensure that the same
package from two slightly different locations is always built the same way.

Sadly I'm not quite sure how to add a test for this as it involves using remote
git urls which are unusable during tests.

src/cargo/core/package_id.rs

@@ -118,11 +118,11 @@ impl PackageId {
     }
 
     pub fn generate_metadata(&self) -> Metadata {
-        let metadata = format!("{}:-:{}:-:{}", self.name, self.version, self.source_id);
-        let extra_filename = short_hash(
+        let metadata = short_hash(
             &(self.name.as_slice(), self.version.to_string(), &self.source_id));
+        let extra_filename = format!("-{}", metadata);
 
-        Metadata { metadata: metadata, extra_filename: format!("-{}", extra_filename) }
+        Metadata { metadata: metadata, extra_filename: extra_filename }
     }
 }
 

src/cargo/ops/cargo_rustc/fingerprint.rs

@@ -71,7 +71,7 @@ pub fn prepare(cx: &mut Context, pkg: &Package,
 fn is_fresh(dep: &Package, loc: &Path, cx: &mut Context, targets: &[&Target])
             -> CargoResult<(bool, String)> {
     let new_pkg_fingerprint = format!("{}{}", cx.rustc_version,
-                                  try!(dep.get_fingerprint(cx.config)));
+                                      try!(dep.get_fingerprint(cx.config)));
 
     let new_fingerprint = fingerprint(new_pkg_fingerprint, hash_targets(targets));
 

tests/test_cargo_compile.rs

@@ -990,12 +990,12 @@ test!(verbose_build {
     let output = p.cargo_process("cargo-build").arg("-v")
                   .exec_with_output().assert();
     let out = str::from_utf8(output.output.as_slice()).assert();
-    let hash = out.slice_from(out.find_str("extra-filename=").unwrap() + 15);
-    let hash = hash.slice_to(17);
+    let hash = out.slice_from(out.find_str("extra-filename=").unwrap() + 16);
+    let hash = hash.slice_to(16);
     assert_eq!(out, format!("\
 {} `rustc {dir}{sep}src{sep}lib.rs --crate-name test --crate-type lib \
-        -C metadata=test:-:0.0.0:-:file:{dir} \
-        -C extra-filename={hash} \
+        -C metadata={hash} \
+        -C extra-filename=-{hash} \
         --out-dir {dir}{sep}target \
         -L {dir}{sep}target \
         -L {dir}{sep}target{sep}deps`
@@ -1020,14 +1020,14 @@ test!(verbose_release_build {
     let output = p.cargo_process("cargo-build").arg("-v").arg("--release")
                   .exec_with_output().assert();
     let out = str::from_utf8(output.output.as_slice()).assert();
-    let hash = out.slice_from(out.find_str("extra-filename=").unwrap() + 15);
-    let hash = hash.slice_to(17);
+    let hash = out.slice_from(out.find_str("extra-filename=").unwrap() + 16);
+    let hash = hash.slice_to(16);
     assert_eq!(out, format!("\
 {} `rustc {dir}{sep}src{sep}lib.rs --crate-name test --crate-type lib \
         --opt-level 3 \
         --cfg ndebug \
-        -C metadata=test:-:0.0.0:-:file:{dir} \
-        -C extra-filename={hash} \
+        -C metadata={hash} \
+        -C extra-filename=-{hash} \
         --out-dir {dir}{sep}target{sep}release \
         -L {dir}{sep}target{sep}release \
         -L {dir}{sep}target{sep}release{sep}deps`
@@ -1068,30 +1068,30 @@ test!(verbose_release_build_deps {
                   .exec_with_output().assert();
     let out = str::from_utf8(output.output.as_slice()).assert();
     let pos1 = out.find_str("extra-filename=").unwrap();
-    let hash1 = out.slice_from(pos1 + 15).slice_to(17);
+    let hash1 = out.slice_from(pos1 + 16).slice_to(16);
     let pos2 = out.slice_from(pos1 + 10).find_str("extra-filename=").unwrap();
-    let hash2 = out.slice_from(pos1 + 10 + pos2 + 15).slice_to(17);
+    let hash2 = out.slice_from(pos1 + 10 + pos2 + 16).slice_to(16);
     assert_eq!(out, format!("\
 {running} `rustc {dir}{sep}foo{sep}src{sep}lib.rs --crate-name foo \
         --crate-type dylib --crate-type rlib \
         --opt-level 3 \
         --cfg ndebug \
-        -C metadata=foo:-:0.0.0:-:file:{dir} \
-        -C extra-filename={hash1} \
+        -C metadata={hash1} \
+        -C extra-filename=-{hash1} \
         --out-dir {dir}{sep}target{sep}release{sep}deps \
         -L {dir}{sep}target{sep}release{sep}deps \
         -L {dir}{sep}target{sep}release{sep}deps`
 {running} `rustc {dir}{sep}src{sep}lib.rs --crate-name test --crate-type lib \
         --opt-level 3 \
         --cfg ndebug \
-        -C metadata=test:-:0.0.0:-:file:{dir} \
-        -C extra-filename={hash2} \
+        -C metadata={hash2} \
+        -C extra-filename=-{hash2} \
         --out-dir {dir}{sep}target{sep}release \
         -L {dir}{sep}target{sep}release \
         -L {dir}{sep}target{sep}release{sep}deps \
         --extern foo={dir}{sep}target{sep}release{sep}deps/\
-                     {prefix}foo{hash1}{suffix} \
-        --extern foo={dir}{sep}target{sep}release{sep}deps/libfoo{hash1}.rlib`
+                     {prefix}foo-{hash1}{suffix} \
+        --extern foo={dir}{sep}target{sep}release{sep}deps/libfoo-{hash1}.rlib`
 {compiling} foo v0.0.0 (file:{dir})
 {compiling} test v0.0.0 (file:{dir})\n",
                     running = RUNNING,

tests/test_cargo_compile_git_deps.rs

@@ -1,4 +1,4 @@
-use std::io::{File, TempDir};
+use std::io::File;
 
 use support::{ProjectBuilder, ResultTest, project, execs, main_file, paths};
 use support::{cargo_dir};