Merge bitcoin#15869: Add settings merge test to prevent regresssions

151f3e9 Add settings merge test to prevent regresssions (Russell Yanofsky)

Pull request description:

  Test-only change. Motivation: I'm trying to clean up settings code and add support for read/write settings without changing existing behavior, but current tests are very scattershot and don't actually cover a lot of current behavior.

ACKs for commit 151f3e:
  jonasschnelli:
    utACK 151f3e9.
  MarcoFalke:
    utACK 151f3e9

Tree-SHA512: f9062f078da02855cdbdcae37d0cea5684e82adbe5c701a8eb042ee4a57d899f0ffb6a9db3bcf58b639dff22b2b2d8a75f9a7917402df58904036753d65a1e3e

src/test/util_tests.cpp

@@ -147,6 +147,9 @@ struct TestArgsManager : public ArgsManager
             AddArg(args[i], "", false, OptionsCategory::OPTIONS);
         }
     }
+    using ArgsManager::ReadConfigStream;
+    using ArgsManager::cs_args;
+    using ArgsManager::m_network;
 };
 
 BOOST_AUTO_TEST_CASE(util_ParseParameters)
@@ -564,6 +567,232 @@ BOOST_AUTO_TEST_CASE(util_GetChainName)
     BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
 }
 
+// Test different ways settings can be merged, and verify results. This test can
+// be used to confirm that updates to settings code don't change behavior
+// unintentially.
+//
+// The test covers:
+//
+// - Combining different setting actions. Possible actions are: configuring a
+//   setting, negating a setting (adding "-no" prefix), and configuring/negating
+//   settings in a network section (adding "main." or "test." prefixes).
+//
+// - Combining settings from command line arguments and a config file.
+//
+// - Combining SoftSet and ForceSet calls.
+//
+// - Testing "main" and "test" network values to make sure settings from network
+//   sections are applied and to check for mainnet-specific behaviors like
+//   inheriting settings from the default section.
+//
+// - Testing network-specific settings like "-wallet", that may be ignored
+//   outside a network section, and non-network specific settings like "-server"
+//   that aren't sensitive to the network.
+//
+struct SettingsMergeTestingSetup : public BasicTestingSetup {
+    //! Max number of actions to sequence together. Can decrease this when
+    //! debugging to make test results easier to understand.
+    static constexpr int MAX_ACTIONS = 3;
+
+    enum Action { SET = 0, NEGATE, SECTION_SET, SECTION_NEGATE, END };
+    using ActionList = Action[MAX_ACTIONS];
+
+    //! Enumerate all possible test configurations.
+    template <typename Fn>
+    void ForEachMergeSetup(Fn&& fn)
+    {
+        ForEachActionList([&](const ActionList& arg_actions) {
+            ForEachActionList([&](const ActionList& conf_actions) {
+                for (bool soft_set : {false, true}) {
+                    for (bool force_set : {false, true}) {
+                        for (const std::string& section : {CBaseChainParams::MAIN, CBaseChainParams::TESTNET}) {
+                            for (const std::string& network : {CBaseChainParams::MAIN, CBaseChainParams::TESTNET}) {
+                                for (bool net_specific : {false, true}) {
+                                    fn(arg_actions, conf_actions, soft_set, force_set, section, network, net_specific);
+                                }
+                            }
+                        }
+                    }
+                }
+            });
+        });
+    }
+
+    //! Enumerate interesting combinations of actions.
+    template <typename Fn>
+    void ForEachActionList(Fn&& fn)
+    {
+        ActionList actions = {SET};
+        for (bool done = false; !done;) {
+            int prev_action = -1;
+            bool skip_actions = false;
+            for (Action action : actions) {
+                if ((prev_action == END && action != END) || (prev_action != END && action == prev_action)) {
+                    // To cut down list of enumerated settings, skip enumerating
+                    // settings with ignored actions after an END, and settings that
+                    // repeat the same action twice in a row.
+                    skip_actions = true;
+                    break;
+                }
+                prev_action = action;
+            }
+            if (!skip_actions) fn(actions);
+            done = true;
+            for (Action& action : actions) {
+                action = Action(action < END ? action + 1 : 0);
+                if (action) {
+                    done = false;
+                    break;
+                }
+            }
+        }
+    }
+
+    //! Translate actions into a list of <key>=<value> setting strings.
+    std::vector<std::string> GetValues(const ActionList& actions,
+        const std::string& section,
+        const std::string& name,
+        const std::string& value_prefix)
+    {
+        std::vector<std::string> values;
+        int suffix = 0;
+        for (Action action : actions) {
+            if (action == END) break;
+            std::string prefix;
+            if (action == SECTION_SET || action == SECTION_NEGATE) prefix = section + ".";
+            if (action == SET || action == SECTION_SET) {
+                for (int i = 0; i < 2; ++i) {
+                    values.push_back(prefix + name + "=" + value_prefix + std::to_string(++suffix));
+                }
+            }
+            if (action == NEGATE || action == SECTION_NEGATE) {
+                values.push_back(prefix + "no" + name + "=1");
+            }
+        }
+        return values;
+    }
+};
+
+// Regression test covering different ways config settings can be merged. The
+// test parses and merges settings, representing the results as strings that get
+// compared against an expected hash. To debug, the result strings can be dumped
+// to a file (see below).
+BOOST_FIXTURE_TEST_CASE(util_SettingsMerge, SettingsMergeTestingSetup)
+{
+    CHash256 out_sha;
+    FILE* out_file = nullptr;
+    if (const char* out_path = getenv("SETTINGS_MERGE_TEST_OUT")) {
+        out_file = fsbridge::fopen(out_path, "w");
+        if (!out_file) throw std::system_error(errno, std::generic_category(), "fopen failed");
+    }
+
+    ForEachMergeSetup([&](const ActionList& arg_actions, const ActionList& conf_actions, bool soft_set, bool force_set,
+                          const std::string& section, const std::string& network, bool net_specific) {
+        TestArgsManager parser;
+        LOCK(parser.cs_args);
+
+        std::string desc = "net=";
+        desc += network;
+        parser.m_network = network;
+
+        const std::string& name = net_specific ? "server" : "wallet";
+        const std::string key = "-" + name;
+        parser.AddArg(key, name, false, OptionsCategory::OPTIONS);
+        if (net_specific) parser.SetNetworkOnlyArg(key);
+
+        auto args = GetValues(arg_actions, section, name, "a");
+        std::vector<const char*> argv = {"ignored"};
+        for (auto& arg : args) {
+            arg.insert(0, "-");
+            desc += " ";
+            desc += arg;
+            argv.push_back(arg.c_str());
+        }
+        std::string error;
+        BOOST_CHECK(parser.ParseParameters(argv.size(), argv.data(), error));
+        BOOST_CHECK_EQUAL(error, "");
+
+        std::string conf;
+        for (auto& conf_val : GetValues(conf_actions, section, name, "c")) {
+            desc += " ";
+            desc += conf_val;
+            conf += conf_val;
+            conf += "\n";
+        }
+        std::istringstream conf_stream(conf);
+        BOOST_CHECK(parser.ReadConfigStream(conf_stream, "filepath", error));
+        BOOST_CHECK_EQUAL(error, "");
+
+        if (soft_set) {
+            desc += " soft";
+            parser.SoftSetArg(key, "soft1");
+            parser.SoftSetArg(key, "soft2");
+        }
+
+        if (force_set) {
+            desc += " force";
+            parser.ForceSetArg(key, "force1");
+            parser.ForceSetArg(key, "force2");
+        }
+
+        desc += " || ";
+
+        if (!parser.IsArgSet(key)) {
+            desc += "unset";
+            BOOST_CHECK(!parser.IsArgNegated(key));
+            BOOST_CHECK_EQUAL(parser.GetArg(key, "default"), "default");
+            BOOST_CHECK(parser.GetArgs(key).empty());
+        } else if (parser.IsArgNegated(key)) {
+            desc += "negated";
+            BOOST_CHECK_EQUAL(parser.GetArg(key, "default"), "0");
+            BOOST_CHECK(parser.GetArgs(key).empty());
+        } else {
+            desc += parser.GetArg(key, "default");
+            desc += " |";
+            for (const auto& arg : parser.GetArgs(key)) {
+                desc += " ";
+                desc += arg;
+            }
+        }
+
+        std::set<std::string> ignored = parser.GetUnsuitableSectionOnlyArgs();
+        if (!ignored.empty()) {
+            desc += " | ignored";
+            for (const auto& arg : ignored) {
+                desc += " ";
+                desc += arg;
+            }
+        }
+
+        desc += "\n";
+
+        out_sha.Write((const unsigned char*)desc.data(), desc.size());
+        if (out_file) {
+            BOOST_REQUIRE(fwrite(desc.data(), 1, desc.size(), out_file) == desc.size());
+        }
+    });
+
+    if (out_file) {
+        if (fclose(out_file)) throw std::system_error(errno, std::generic_category(), "fclose failed");
+        out_file = nullptr;
+    }
+
+    unsigned char out_sha_bytes[CSHA256::OUTPUT_SIZE];
+    out_sha.Finalize(out_sha_bytes);
+    std::string out_sha_hex = HexStr(std::begin(out_sha_bytes), std::end(out_sha_bytes));
+
+    // If check below fails, should manually dump the results with:
+    //
+    //   SETTINGS_MERGE_TEST_OUT=results.txt ./test_bitcoin --run_test=util_tests/util_SettingsMerge
+    //
+    // And verify diff against previous results to make sure the changes are expected.
+    //
+    // Results file is formatted like:
+    //
+    //   <input> || <IsArgSet/IsArgNegated/GetArg output> | <GetArgs output> | <GetUnsuitable output>
+    BOOST_CHECK_EQUAL(out_sha_hex, "80964e17fbd3c5569d3c824d032e28e2d319ef57494735b0e76eb7aad9957f2c");
+}
+
 BOOST_AUTO_TEST_CASE(util_FormatMoney)
 {
     BOOST_CHECK_EQUAL(FormatMoney(0), "0.00");