Merge #20828: fuzz: Introduce CallOneOf helper to replace switch-case

fa75d40ef866ef9ff8dc115e239ca6763aa23b06 fuzz: Introduce CallOneOf helper to replace switch-case (MarcoFalke)

Pull request description:

  The current `switch (fuzzed_data_provider.ConsumeIntegralInRange<int>(0, nn)) { case 0: ... case 1: ... case nn: ...` has several problems:

  * It makes it hard to review newly added targets, because it requires manual counting of cases
  * It makes it hard to update a target, because updating all case labels is trivial, but tedious to review and causes merge conflicts
  * ~~Updating the target raises the question whether the case labels should be preserved to not invalidate the existing fuzz inputs format. Fuzz input format might already change implicitly on every commit, so this isn't something worthwhile to pursue.~~ Edit: This pull doesn't fix this problem.

  Fix all issues by adding a new `CallOneOf` helper

ACKs for top commit:
  ajtowns:
    ACK fa75d40ef866ef9ff8dc115e239ca6763aa23b06 - code review only
  jnewbery:
    utACK fa75d40ef866ef9ff8dc115e239ca6763aa23b06

Tree-SHA512: 2daa602b240b86c8e85a024e008f03a57ba60349377eed771f4d21a97a9dba9b66e93fff16ff1992018d4330be7a1a276944c3dfdf698748ce135626c380e563

1 files changed, 32 insertions, 36 deletions

diff --git a/src/test/fuzz/policy_estimator.cpp b/src/test/fuzz/policy_estimator.cpp
index 35cfc5230b..0393491e4b 100644
--- a/src/test/fuzz/policy_estimator.cpp
+++ b/src/test/fuzz/policy_estimator.cpp
@@ -24,46 +24,42 @@ FUZZ_TARGET_INIT(policy_estimator, initialize_policy_estimator)
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     CBlockPolicyEstimator block_policy_estimator;
     while (fuzzed_data_provider.ConsumeBool()) {
-        switch (fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 3)) {
-        case 0: {
-            const std::optional<CMutableTransaction> mtx = ConsumeDeserializable<CMutableTransaction>(fuzzed_data_provider);
-            if (!mtx) {
-                break;
-            }
-            const CTransaction tx{*mtx};
-            block_policy_estimator.processTransaction(ConsumeTxMemPoolEntry(fuzzed_data_provider, tx), fuzzed_data_provider.ConsumeBool());
-            if (fuzzed_data_provider.ConsumeBool()) {
-                (void)block_policy_estimator.removeTx(tx.GetHash(), /* inBlock */ fuzzed_data_provider.ConsumeBool());
-            }
-            break;
-        }
-        case 1: {
-            std::vector<CTxMemPoolEntry> mempool_entries;
-            while (fuzzed_data_provider.ConsumeBool()) {
+        CallOneOf(
+            fuzzed_data_provider,
+            [&] {
                 const std::optional<CMutableTransaction> mtx = ConsumeDeserializable<CMutableTransaction>(fuzzed_data_provider);
                 if (!mtx) {
-                    break;
+                    return;
                 }
                 const CTransaction tx{*mtx};
-                mempool_entries.push_back(ConsumeTxMemPoolEntry(fuzzed_data_provider, tx));
-            }
-            std::vector<const CTxMemPoolEntry*> ptrs;
-            ptrs.reserve(mempool_entries.size());
-            for (const CTxMemPoolEntry& mempool_entry : mempool_entries) {
-                ptrs.push_back(&mempool_entry);
-            }
-            block_policy_estimator.processBlock(fuzzed_data_provider.ConsumeIntegral<unsigned int>(), ptrs);
-            break;
-        }
-        case 2: {
-            (void)block_policy_estimator.removeTx(ConsumeUInt256(fuzzed_data_provider), /* inBlock */ fuzzed_data_provider.ConsumeBool());
-            break;
-        }
-        case 3: {
-            block_policy_estimator.FlushUnconfirmed();
-            break;
-        }
-        }
+                block_policy_estimator.processTransaction(ConsumeTxMemPoolEntry(fuzzed_data_provider, tx), fuzzed_data_provider.ConsumeBool());
+                if (fuzzed_data_provider.ConsumeBool()) {
+                    (void)block_policy_estimator.removeTx(tx.GetHash(), /* inBlock */ fuzzed_data_provider.ConsumeBool());
+                }
+            },
+            [&] {
+                std::vector<CTxMemPoolEntry> mempool_entries;
+                while (fuzzed_data_provider.ConsumeBool()) {
+                    const std::optional<CMutableTransaction> mtx = ConsumeDeserializable<CMutableTransaction>(fuzzed_data_provider);
+                    if (!mtx) {
+                        break;
+                    }
+                    const CTransaction tx{*mtx};
+                    mempool_entries.push_back(ConsumeTxMemPoolEntry(fuzzed_data_provider, tx));
+                }
+                std::vector<const CTxMemPoolEntry*> ptrs;
+                ptrs.reserve(mempool_entries.size());
+                for (const CTxMemPoolEntry& mempool_entry : mempool_entries) {
+                    ptrs.push_back(&mempool_entry);
+                }
+                block_policy_estimator.processBlock(fuzzed_data_provider.ConsumeIntegral<unsigned int>(), ptrs);
+            },
+            [&] {
+                (void)block_policy_estimator.removeTx(ConsumeUInt256(fuzzed_data_provider), /* inBlock */ fuzzed_data_provider.ConsumeBool());
+            },
+            [&] {
+                block_policy_estimator.FlushUnconfirmed();
+            });
         (void)block_policy_estimator.estimateFee(fuzzed_data_provider.ConsumeIntegral<int>());
         EstimationResult result;
         (void)block_policy_estimator.estimateRawFee(fuzzed_data_provider.ConsumeIntegral<int>(), fuzzed_data_provider.ConsumeFloatingPoint<double>(), fuzzed_data_provider.PickValueInArray(ALL_FEE_ESTIMATE_HORIZONS), fuzzed_data_provider.ConsumeBool() ? &result : nullptr);