Merge pull request NixOS#28 from obsidiansystems/better-error-for-ipf…

…s-address-mismatch

Better error for ipfs address mismatch

src/libstore/ipfs-binary-cache-store.cc

@@ -190,15 +190,22 @@ class IPFSBinaryCacheStore : public Store
     }
 
 public:
+    Path formatPathAsProtocol(Path path) {
+        if (hasPrefix(path, "/ipfs/"))
+            return "ipfs://" + path.substr(strlen("/ipfs/"), string::npos);
+        else if (hasPrefix(path, "/ipns/"))
+            return "ipns://" + path.substr(strlen("/ipfs/"), string::npos);
+        else return path;
+    }
 
     // IPNS publish can be slow, we try to do it rarely.
     void sync() override
     {
         auto state(_state.lock());
 
         if (!optIpnsPath) {
-            throw Error("We don't have an ipns path and the current ipfs address doesn't match the initial one.\n  current: %s\n  initial: %s",
-                state->ipfsPath, initialIpfsPath);
+            throw Error("The current IPFS address doesn't match the configured one. \n  initial: %s\n  current: %s",
+                formatPathAsProtocol(initialIpfsPath), formatPathAsProtocol(state->ipfsPath));
         }
 
         auto ipnsPath = *optIpnsPath;

tests/ipfs.sh

@@ -99,7 +99,7 @@ EMPTY_HASH=$(echo {} | ipfs dag put)
 IPFS_HASH=$(set -e; \
   set -o pipefail; \
   ! nix copy --to ipfs://$EMPTY_HASH $(nix-build ./fixed.nix -A good) --experimental-features nix-command \
-    |& grep current: | awk '{print substr($2, 7, length($2))}')
+    |& grep current: | awk '{print substr($2, 8, length($2))}')
 
 # Verify that new path is valid.
 nix copy --to ipfs://$IPFS_HASH $(nix-build ./fixed.nix -A good) --experimental-features nix-command