`LocalStore::verifyPath`: Try to clarify data flow with more scopes

It was initially unclear to me which of these are temporary state for
the verify paths computation, and which of these are the results of that
computation to be used in the rest of the function. Now, it is clear,
and enforced.

1 files changed, 15 insertions, 12 deletions

diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 9049f33aa..17e2ebc38 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -1499,21 +1499,24 @@ bool LocalStore::verifyStore(bool checkContents, RepairFlag repair)
     auto fdGCLock = openGCLock();
     FdLock gcLock(fdGCLock.get(), ltRead, true, "waiting for the big garbage collector lock...");
 
-    StorePathSet store;
-    for (auto & i : readDirectory(realStoreDir)) {
-        try {
-            store.insert({i.name});
-        } catch (BadStorePath &) { }
-    }
+    StorePathSet validPaths;
 
-    /* Check whether all valid paths actually exist. */
-    printInfo("checking path existence...");
+    {
+        StorePathSet store;
+        for (auto & i : readDirectory(realStoreDir)) {
+            try {
+                store.insert({i.name});
+            } catch (BadStorePath &) { }
+        }
 
-    StorePathSet validPaths;
-    StorePathSet done;
+        /* Check whether all valid paths actually exist. */
+        printInfo("checking path existence...");
 
-    for (auto & i : queryAllValidPaths())
-        verifyPath(i, store, done, validPaths, repair, errors);
+        StorePathSet done;
+
+        for (auto & i : queryAllValidPaths())
+            verifyPath(i, store, done, validPaths, repair, errors);
+    }
 
     /* Optionally, check the content hashes (slow). */
     if (checkContents) {