Auto merge of #1120 - crazymerlyn:checksum_fail_is_ok, r=Diggsey

Exit successfully on "update not yet available"

Fixes #990.

Author: bors

src/rustup-dist/src/dist.rs

@@ -667,6 +667,9 @@ pub fn update_from_dist_<'a>(download: DownloadCfg<'a>,
             // Proceed to try v1 as a fallback
             (download.notify_handler)(Notification::DownloadingLegacyManifest);
         }
+        Err(Error(ErrorKind::ChecksumFailed { .. }, _)) => {
+            return Ok(None)
+        }
         Err(e) => return Err(e),
     }
 

src/rustup/toolchain.rs

@@ -123,7 +123,7 @@ impl<'a> Toolchain<'a> {
             (true, false) => UpdateStatus::Installed,
             (true, true) => UpdateStatus::Updated,
             (false, true) => UpdateStatus::Unchanged,
-            (false, false) => unreachable!(),
+            (false, false) => UpdateStatus::Unchanged,
         };
 
         Ok(status)

tests/cli-v2.rs

@@ -198,8 +198,7 @@ fn bad_sha_on_manifest() {
         sha_bytes[..10].clone_from_slice(b"aaaaaaaaaa");
         let sha_str = String::from_utf8(sha_bytes).unwrap();
         rustup_utils::raw::write_file(&sha_file, &sha_str).unwrap();
-        expect_err(config, &["rustup", "default", "nightly"],
-                   "checksum failed");
+        expect_ok(config, &["rustup", "default", "nightly"]);
     });
 }