Merge dashpay#6722: fix: missing mutex for bls::operator==

a488c8d fix: add missing mutex to operator== for bls wrapper (Konstantin Akimov)

Pull request description:

  ## Issue being fixed or feature implemented
  Somehow, CBLSLazyWrapper works correctly till now and does not cause any failures even `CBLSLazyWrapper::operator==()` doesn't have mutex inside. Let's fix it!

  ## What was done?
  Added mutex to operator== for CBLSWrapper; added ptrs comparision to operator== in case of compare `A==A` to avoid deadlock.

  ## How Has This Been Tested?
  Run unit / functional tests.

  ## Breaking Changes
  N/A

  ## Checklist:
  - [x] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone

ACKs for top commit:
  UdjinM6:
    utACK a488c8d

Tree-SHA512: cef814a451d12b1ee2b548ddfe4c147690f1704dd5068821fae8d617ff2013c76862be6dae763a78abd233465b23f164af7631ebe39c72b067a853f4ee19f663

Author: PastaPastaPasta

src/bls/bls.h

@@ -509,19 +509,23 @@ class CBLSLazyWrapper
 
     bool operator==(const CBLSLazyWrapper& r) const
     {
-        // If neither bufValid or objInitialized are set, then the object is the default object.
-        const bool is_default{!bufValid && !objInitialized};
-        const bool r_is_default{!r.bufValid && !r.objInitialized};
-        // If both are default; they are equal.
-        if (is_default && r_is_default) return true;
-        // If one is default and the other isn't, we are not equal
-        if (is_default != r_is_default) return false;
-
-        if (bufValid && r.bufValid && bufLegacyScheme == r.bufLegacyScheme) {
-            return vecBytes == r.vecBytes;
-        }
-        if (objInitialized && r.objInitialized) {
-            return obj == r.obj;
+        if (&r == this) return true;
+        {
+            std::scoped_lock lock(mutex, r.mutex);
+            // If neither bufValid or objInitialized are set, then the object is the default object.
+            const bool is_default{!bufValid && !objInitialized};
+            const bool r_is_default{!r.bufValid && !r.objInitialized};
+            // If both are default; they are equal.
+            if (is_default && r_is_default) return true;
+            // If one is default and the other isn't, we are not equal
+            if (is_default != r_is_default) return false;
+
+            if (bufValid && r.bufValid && bufLegacyScheme == r.bufLegacyScheme) {
+                return vecBytes == r.vecBytes;
+            }
+            if (objInitialized && r.objInitialized) {
+                return obj == r.obj;
+            }
         }
         return Get() == r.Get();
     }