Merge bitcoin/bitcoin#27902: fuzz: wallet, add target for CoinControl

40b333e fuzz: wallet, add target for CoinControl (Ayush Singh)

Pull request description:

  This PR adds fuzz coverage for `wallet/coincontrol`.

  Motivation: Issue [#27272](bitcoin/bitcoin#27272 (comment))

  The idea is to create different/unique instances of `COutPoint` by placing it inside the `CallOneOf` function, which may or may not be consumed by all of the `CoinControl` file's methods.

  This is my first PR on Bitcoin Core, and I will try my best to address any reviews/changes ASAP. I'm also working on fuzz harness files for other files in the wallet and plan to open PR for them soon.

ACKs for top commit:
  kevkevinpal:
    reACK [40b333e](bitcoin/bitcoin@40b333e)
  MarcoFalke:
    lgtm ACK 40b333e
  achow101:
    ACK 40b333e
  brunoerg:
    crACK 40b333e
  dergoegge:
    ACK 40b333e

Tree-SHA512: 174769f4e86df8590b532b85480fd620082587e84e50e49ca9b52f0588a219355362cefd66250dd9942e86019d27af4ca599b45e871e9f147d2cc0ba97c4aa7b

Author: achow101

src/Makefile.test.include

@@ -194,6 +194,7 @@ BITCOIN_TESTS += wallet/test/db_tests.cpp
 endif
 
 FUZZ_WALLET_SRC = \
+ wallet/test/fuzz/coincontrol.cpp \
  wallet/test/fuzz/coinselection.cpp \
  wallet/test/fuzz/fees.cpp \
  wallet/test/fuzz/parse_iso8601.cpp

src/wallet/test/fuzz/coincontrol.cpp

@@ -0,0 +1,87 @@
+// Copyright (c) 2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+#include <test/util/setup_common.h>
+#include <wallet/coincontrol.h>
+#include <wallet/test/util.h>
+
+namespace wallet {
+namespace {
+
+const TestingSetup* g_setup;
+
+void initialize_coincontrol()
+{
+    static const auto testing_setup = MakeNoLogFileContext<const TestingSetup>();
+    g_setup = testing_setup.get();
+}
+
+FUZZ_TARGET_INIT(coincontrol, initialize_coincontrol)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    const auto& node = g_setup->m_node;
+    ArgsManager& args = *node.args;
+
+    // for GetBoolArg to return true sometimes
+    args.ForceSetArg("-avoidpartialspends", fuzzed_data_provider.ConsumeBool()?"1":"0");
+
+    CCoinControl coin_control;
+    COutPoint out_point;
+
+    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000)
+    {
+        CallOneOf(
+            fuzzed_data_provider,
+            [&] {
+                std::optional<COutPoint> optional_out_point = ConsumeDeserializable<COutPoint>(fuzzed_data_provider);
+                if (!optional_out_point) {
+                    return;
+                }
+                out_point = *optional_out_point;
+            },
+            [&] {
+                (void)coin_control.HasSelected();
+            },
+            [&] {
+                (void)coin_control.IsSelected(out_point);
+            },
+            [&] {
+                (void)coin_control.IsExternalSelected(out_point);
+            },
+            [&] {
+                (void)coin_control.GetExternalOutput(out_point);
+            },
+            [&] {
+                (void)coin_control.Select(out_point);
+            },
+            [&] {
+                const CTxOut tx_out{ConsumeMoney(fuzzed_data_provider), ConsumeScript(fuzzed_data_provider)};
+                (void)coin_control.SelectExternal(out_point, tx_out);
+            },
+            [&] {
+                (void)coin_control.UnSelect(out_point);
+            },
+            [&] {
+                (void)coin_control.UnSelectAll();
+            },
+            [&] {
+                (void)coin_control.ListSelected();
+            },
+            [&] {
+                int64_t weight{fuzzed_data_provider.ConsumeIntegral<int64_t>()};
+                (void)coin_control.SetInputWeight(out_point, weight);
+            },
+            [&] {
+                // Condition to avoid the assertion in GetInputWeight
+                if (coin_control.HasInputWeight(out_point)) {
+                    (void)coin_control.GetInputWeight(out_point);
+                }
+            });
+    }
+}
+} // namespace
+} // namespace wallet