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, 93 insertions, 99 deletions

diff --git a/src/test/fuzz/scriptnum_ops.cpp b/src/test/fuzz/scriptnum_ops.cpp
index 650318f13c..bc4867839c 100644
--- a/src/test/fuzz/scriptnum_ops.cpp
+++ b/src/test/fuzz/scriptnum_ops.cpp
@@ -29,105 +29,99 @@ FUZZ_TARGET(scriptnum_ops)
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     CScriptNum script_num = ConsumeScriptNum(fuzzed_data_provider);
     while (fuzzed_data_provider.remaining_bytes() > 0) {
-        switch (fuzzed_data_provider.ConsumeIntegralInRange(0, 11)) {
-        case 0: {
-            const int64_t i = fuzzed_data_provider.ConsumeIntegral<int64_t>();
-            assert((script_num == i) != (script_num != i));
-            assert((script_num <= i) != (script_num > i));
-            assert((script_num >= i) != (script_num < i));
-            // Avoid signed integer overflow:
-            // script/script.h:264:93: runtime error: signed integer overflow: -2261405121394637306 + -9223372036854775802 cannot be represented in type 'long'
-            if (IsValidAddition(script_num, CScriptNum{i})) {
-                assert((script_num + i) - i == script_num);
-            }
-            // Avoid signed integer overflow:
-            // script/script.h:265:93: runtime error: signed integer overflow: 9223371895120855039 - -9223372036854710486 cannot be represented in type 'long'
-            if (IsValidSubtraction(script_num, CScriptNum{i})) {
-                assert((script_num - i) + i == script_num);
-            }
-            break;
-        }
-        case 1: {
-            const CScriptNum random_script_num = ConsumeScriptNum(fuzzed_data_provider);
-            assert((script_num == random_script_num) != (script_num != random_script_num));
-            assert((script_num <= random_script_num) != (script_num > random_script_num));
-            assert((script_num >= random_script_num) != (script_num < random_script_num));
-            // Avoid signed integer overflow:
-            // script/script.h:264:93: runtime error: signed integer overflow: -9223126527765971126 + -9223372036854756825 cannot be represented in type 'long'
-            if (IsValidAddition(script_num, random_script_num)) {
-                assert((script_num + random_script_num) - random_script_num == script_num);
-            }
-            // Avoid signed integer overflow:
-            // script/script.h:265:93: runtime error: signed integer overflow: 6052837899185946624 - -9223372036854775808 cannot be represented in type 'long'
-            if (IsValidSubtraction(script_num, random_script_num)) {
-                assert((script_num - random_script_num) + random_script_num == script_num);
-            }
-            break;
-        }
-        case 2: {
-            const CScriptNum random_script_num = ConsumeScriptNum(fuzzed_data_provider);
-            if (!IsValidAddition(script_num, random_script_num)) {
-                // Avoid assertion failure:
-                // ./script/script.h:292: CScriptNum &CScriptNum::operator+=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value <= std::numeric_limits<int64_t>::max() - rhs) || (rhs < 0 && m_value >= std::numeric_limits<int64_t>::min() - rhs)' failed.
-                break;
-            }
-            script_num += random_script_num;
-            break;
-        }
-        case 3: {
-            const CScriptNum random_script_num = ConsumeScriptNum(fuzzed_data_provider);
-            if (!IsValidSubtraction(script_num, random_script_num)) {
-                // Avoid assertion failure:
-                // ./script/script.h:300: CScriptNum &CScriptNum::operator-=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value >= std::numeric_limits<int64_t>::min() + rhs) || (rhs < 0 && m_value <= std::numeric_limits<int64_t>::max() + rhs)' failed.
-                break;
-            }
-            script_num -= random_script_num;
-            break;
-        }
-        case 4:
-            script_num = script_num & fuzzed_data_provider.ConsumeIntegral<int64_t>();
-            break;
-        case 5:
-            script_num = script_num & ConsumeScriptNum(fuzzed_data_provider);
-            break;
-        case 6:
-            script_num &= ConsumeScriptNum(fuzzed_data_provider);
-            break;
-        case 7:
-            if (script_num == CScriptNum{std::numeric_limits<int64_t>::min()}) {
-                // Avoid assertion failure:
-                // ./script/script.h:279: CScriptNum CScriptNum::operator-() const: Assertion `m_value != std::numeric_limits<int64_t>::min()' failed.
-                break;
-            }
-            script_num = -script_num;
-            break;
-        case 8:
-            script_num = fuzzed_data_provider.ConsumeIntegral<int64_t>();
-            break;
-        case 9: {
-            const int64_t random_integer = fuzzed_data_provider.ConsumeIntegral<int64_t>();
-            if (!IsValidAddition(script_num, CScriptNum{random_integer})) {
-                // Avoid assertion failure:
-                // ./script/script.h:292: CScriptNum &CScriptNum::operator+=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value <= std::numeric_limits<int64_t>::max() - rhs) || (rhs < 0 && m_value >= std::numeric_limits<int64_t>::min() - rhs)' failed.
-                break;
-            }
-            script_num += random_integer;
-            break;
-        }
-        case 10: {
-            const int64_t random_integer = fuzzed_data_provider.ConsumeIntegral<int64_t>();
-            if (!IsValidSubtraction(script_num, CScriptNum{random_integer})) {
-                // Avoid assertion failure:
-                // ./script/script.h:300: CScriptNum &CScriptNum::operator-=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value >= std::numeric_limits<int64_t>::min() + rhs) || (rhs < 0 && m_value <= std::numeric_limits<int64_t>::max() + rhs)' failed.
-                break;
-            }
-            script_num -= random_integer;
-            break;
-        }
-        case 11:
-            script_num &= fuzzed_data_provider.ConsumeIntegral<int64_t>();
-            break;
-        }
+        CallOneOf(
+            fuzzed_data_provider,
+            [&] {
+                const int64_t i = fuzzed_data_provider.ConsumeIntegral<int64_t>();
+                assert((script_num == i) != (script_num != i));
+                assert((script_num <= i) != (script_num > i));
+                assert((script_num >= i) != (script_num < i));
+                // Avoid signed integer overflow:
+                // script/script.h:264:93: runtime error: signed integer overflow: -2261405121394637306 + -9223372036854775802 cannot be represented in type 'long'
+                if (IsValidAddition(script_num, CScriptNum{i})) {
+                    assert((script_num + i) - i == script_num);
+                }
+                // Avoid signed integer overflow:
+                // script/script.h:265:93: runtime error: signed integer overflow: 9223371895120855039 - -9223372036854710486 cannot be represented in type 'long'
+                if (IsValidSubtraction(script_num, CScriptNum{i})) {
+                    assert((script_num - i) + i == script_num);
+                }
+            },
+            [&] {
+                const CScriptNum random_script_num = ConsumeScriptNum(fuzzed_data_provider);
+                assert((script_num == random_script_num) != (script_num != random_script_num));
+                assert((script_num <= random_script_num) != (script_num > random_script_num));
+                assert((script_num >= random_script_num) != (script_num < random_script_num));
+                // Avoid signed integer overflow:
+                // script/script.h:264:93: runtime error: signed integer overflow: -9223126527765971126 + -9223372036854756825 cannot be represented in type 'long'
+                if (IsValidAddition(script_num, random_script_num)) {
+                    assert((script_num + random_script_num) - random_script_num == script_num);
+                }
+                // Avoid signed integer overflow:
+                // script/script.h:265:93: runtime error: signed integer overflow: 6052837899185946624 - -9223372036854775808 cannot be represented in type 'long'
+                if (IsValidSubtraction(script_num, random_script_num)) {
+                    assert((script_num - random_script_num) + random_script_num == script_num);
+                }
+            },
+            [&] {
+                const CScriptNum random_script_num = ConsumeScriptNum(fuzzed_data_provider);
+                if (!IsValidAddition(script_num, random_script_num)) {
+                    // Avoid assertion failure:
+                    // ./script/script.h:292: CScriptNum &CScriptNum::operator+=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value <= std::numeric_limits<int64_t>::max() - rhs) || (rhs < 0 && m_value >= std::numeric_limits<int64_t>::min() - rhs)' failed.
+                    return;
+                }
+                script_num += random_script_num;
+            },
+            [&] {
+                const CScriptNum random_script_num = ConsumeScriptNum(fuzzed_data_provider);
+                if (!IsValidSubtraction(script_num, random_script_num)) {
+                    // Avoid assertion failure:
+                    // ./script/script.h:300: CScriptNum &CScriptNum::operator-=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value >= std::numeric_limits<int64_t>::min() + rhs) || (rhs < 0 && m_value <= std::numeric_limits<int64_t>::max() + rhs)' failed.
+                    return;
+                }
+                script_num -= random_script_num;
+            },
+            [&] {
+                script_num = script_num & fuzzed_data_provider.ConsumeIntegral<int64_t>();
+            },
+            [&] {
+                script_num = script_num & ConsumeScriptNum(fuzzed_data_provider);
+            },
+            [&] {
+                script_num &= ConsumeScriptNum(fuzzed_data_provider);
+            },
+            [&] {
+                if (script_num == CScriptNum{std::numeric_limits<int64_t>::min()}) {
+                    // Avoid assertion failure:
+                    // ./script/script.h:279: CScriptNum CScriptNum::operator-() const: Assertion `m_value != std::numeric_limits<int64_t>::min()' failed.
+                    return;
+                }
+                script_num = -script_num;
+            },
+            [&] {
+                script_num = fuzzed_data_provider.ConsumeIntegral<int64_t>();
+            },
+            [&] {
+                const int64_t random_integer = fuzzed_data_provider.ConsumeIntegral<int64_t>();
+                if (!IsValidAddition(script_num, CScriptNum{random_integer})) {
+                    // Avoid assertion failure:
+                    // ./script/script.h:292: CScriptNum &CScriptNum::operator+=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value <= std::numeric_limits<int64_t>::max() - rhs) || (rhs < 0 && m_value >= std::numeric_limits<int64_t>::min() - rhs)' failed.
+                    return;
+                }
+                script_num += random_integer;
+            },
+            [&] {
+                const int64_t random_integer = fuzzed_data_provider.ConsumeIntegral<int64_t>();
+                if (!IsValidSubtraction(script_num, CScriptNum{random_integer})) {
+                    // Avoid assertion failure:
+                    // ./script/script.h:300: CScriptNum &CScriptNum::operator-=(const int64_t &): Assertion `rhs == 0 || (rhs > 0 && m_value >= std::numeric_limits<int64_t>::min() + rhs) || (rhs < 0 && m_value <= std::numeric_limits<int64_t>::max() + rhs)' failed.
+                    return;
+                }
+                script_num -= random_integer;
+            },
+            [&] {
+                script_num &= fuzzed_data_provider.ConsumeIntegral<int64_t>();
+            });
         (void)script_num.getint();
         (void)script_num.getvch();
     }