[validation] better handle errors in SubmitPackage

Behavior change: don't quit right after LimitMempoolSize() when a
package is partially submitted. We should still send
TransactionAddedToMempool notifications for
transactions that were submitted.

Not behavior change: add a new package validation result for mempool logic errors.

src/policy/packages.h

@@ -25,6 +25,7 @@ enum class PackageValidationResult {
     PCKG_RESULT_UNSET = 0,        //!< Initial value. The package has not yet been rejected.
     PCKG_POLICY,                  //!< The package itself is invalid (e.g. too many transactions).
     PCKG_TX,                      //!< At least one tx is invalid.
+    PCKG_MEMPOOL_ERROR,           //!< Mempool logic error.
 };
 
 /** A package is an ordered list of transactions. The transactions cannot conflict with (spend the

src/validation.cpp

@@ -1058,7 +1058,10 @@ bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>&
         if (!ConsensusScriptChecks(args, ws)) {
             results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state));
             // Since PolicyScriptChecks() passed, this should never fail.
-            all_submitted = Assume(false);
+            all_submitted = false;
+            package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR,
+                                  strprintf("BUG! PolicyScriptChecks succeeded but ConsensusScriptChecks failed: %s",
+                                            ws.m_ptx->GetHash().ToString()));
         }
 
         // Re-calculate mempool ancestors to call addUnchecked(). They may have changed since the
@@ -1069,7 +1072,10 @@ bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>&
                                              m_limit_descendant_size, unused_err_string)) {
             results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state));
             // Since PreChecks() and PackageMempoolChecks() both enforce limits, this should never fail.
-            all_submitted = Assume(false);
+            all_submitted = false;
+            package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR,
+                                  strprintf("BUG! Mempool ancestors or descendants were underestimated: %s",
+                                            ws.m_ptx->GetHash().ToString()));
         }
         // If we call LimitMempoolSize() for each individual Finalize(), the mempool will not take
         // the transaction's descendant feerate into account because it hasn't seen them yet. Also,
@@ -1079,7 +1085,9 @@ bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>&
         if (!Finalize(args, ws)) {
             results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state));
             // Since LimitMempoolSize() won't be called, this should never fail.
-            all_submitted = Assume(false);
+            all_submitted = false;
+            package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR,
+                                  strprintf("BUG! Adding to mempool failed: %s", ws.m_ptx->GetHash().ToString()));
         }
     }
 
@@ -1088,7 +1096,6 @@ bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>&
     LimitMempoolSize(m_pool, m_active_chainstate.CoinsTip(),
                      gArgs.GetIntArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000,
                      std::chrono::hours{gArgs.GetIntArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY)});
-    if (!all_submitted) return false;
 
     // Find the wtxids of the transactions that made it into the mempool. Allow partial submission,
     // but don't report success unless they all made it into the mempool.
@@ -1194,7 +1201,7 @@ PackageMempoolAcceptResult MemPoolAccept::AcceptMultipleTransactions(const std::
     if (args.m_test_accept) return PackageMempoolAcceptResult(package_state, std::move(results));
 
     if (!SubmitPackage(args, workspaces, package_state, results)) {
-        package_state.Invalid(PackageValidationResult::PCKG_TX, "submission failed");
+        // PackageValidationState filled in by SubmitPackage().
         return PackageMempoolAcceptResult(package_state, std::move(results));
     }