daemon: Raise an error if substituter doesn't send the expected hash.

It was already impossible in practice for 'expectedHashStr' to be empty
if 'status' == "success".

* nix/libstore/build.cc (SubstitutionGoal::finished): Throw 'SubstError'
when 'expectedHashStr' is empty.

1 files changed, 19 insertions, 18 deletions

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index 6cfe7aba7e6..b5551b87aee 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -3040,27 +3040,28 @@ void SubstitutionGoal::finished()
         if (!pathExists(destPath))
             throw SubstError(format("substitute did not produce path `%1%'") % destPath);
 
+        if (expectedHashStr == "")
+            throw SubstError(format("substituter did not communicate hash for `%1'") % storePath);
+
         hash = hashPath(htSHA256, destPath);
 
         /* Verify the expected hash we got from the substituer. */
-        if (expectedHashStr != "") {
-            size_t n = expectedHashStr.find(':');
-            if (n == string::npos)
-                throw Error(format("bad hash from substituter: %1%") % expectedHashStr);
-            HashType hashType = parseHashType(string(expectedHashStr, 0, n));
-            if (hashType == htUnknown)
-                throw Error(format("unknown hash algorithm in `%1%'") % expectedHashStr);
-            Hash expectedHash = parseHash16or32(hashType, string(expectedHashStr, n + 1));
-            Hash actualHash = hashType == htSHA256 ? hash.first : hashPath(hashType, destPath).first;
-            if (expectedHash != actualHash) {
-                if (settings.printBuildTrace)
-                    printMsg(lvlError, format("@ hash-mismatch %1% %2% %3% %4%")
-                             % storePath % "sha256"
-                             % printHash16or32(expectedHash)
-                             % printHash16or32(actualHash));
-                throw SubstError(format("hash mismatch for substituted item `%1%'") % storePath);
-            }
-        }
+        size_t n = expectedHashStr.find(':');
+        if (n == string::npos)
+            throw Error(format("bad hash from substituter: %1%") % expectedHashStr);
+        HashType hashType = parseHashType(string(expectedHashStr, 0, n));
+        if (hashType == htUnknown)
+            throw Error(format("unknown hash algorithm in `%1%'") % expectedHashStr);
+        Hash expectedHash = parseHash16or32(hashType, string(expectedHashStr, n + 1));
+        Hash actualHash = hashType == htSHA256 ? hash.first : hashPath(hashType, destPath).first;
+        if (expectedHash != actualHash) {
+            if (settings.printBuildTrace)
+                printMsg(lvlError, format("@ hash-mismatch %1% %2% %3% %4%")
+                         % storePath % "sha256"
+                         % printHash16or32(expectedHash)
+                         % printHash16or32(actualHash));
+            throw SubstError(format("hash mismatch for substituted item `%1%'") % storePath);
+        }
 
     } catch (SubstError & e) {