Merge bitcoin/bitcoin#27491: refactor: Move chain constants to the util library

d168458d1ff987e0d741c75ac1d4b63ae0cfb7e7 scripted-diff: Remove unused chainparamsbase includes (TheCharlatan)
e9ee8aaf3acdf6dce2b339916d4c602484570050 Add missing definitions in prep for scripted diff (TheCharlatan)
ba8fc7d788932b25864fb260ca14983aa2398c23 refactor: Replace string chain name constants with ChainTypes (TheCharlatan)
401453df419af35957ec711423ac3d93ad512fe8 refactor: Introduce ChainType getters for ArgsManager (TheCharlatan)
bfc21c31b2186f7d30fc9a9ca7d6887ab61c6fb9 refactor: Create chaintype files (TheCharlatan)

Pull request description:

  This pull request is part of the `libbitcoinkernel` project https://github.com/bitcoin/bitcoin/issues/24303 https://github.com/bitcoin/bitcoin/projects/18 and more specifically its "Step 2: Decouple most non-consensus code from libbitcoinkernel". It is also a follow up to #26177.

  It replaces pull request https://github.com/bitcoin/bitcoin/pull/27294, which just moved the constants to a new file, but did not re-declare them as enums.

  The code move of the chain name constants out of the `chainparamsbase` to their own separate header allows the kernel `chainparams` to no longer include `chainparamsbase`. The `chainparamsbase` contain references to the `ArgsManager` and networking related options that should not belong to the kernel library. Besides this move, the constants are re-declared as enums with helper functions facilitating string conversions.

ACKs for top commit:
  ryanofsky:
    Code review ACK d168458d1ff987e0d741c75ac1d4b63ae0cfb7e7. Just suggested changes since last review.

Tree-SHA512: ac2fbe5cbbab4f52eae1e30af1f16700b6589eb4764c328a151a712adfc37f326cc94a65c385534c57d4bc92cc1a13bf1777d92bc924a20dbb30440e7380b316

4 files changed, 68 insertions, 7 deletions

diff --git a/src/util/chaintype.cpp b/src/util/chaintype.cpp
new file mode 100644
index 0000000000..8a199e352a
--- /dev/null
+++ b/src/util/chaintype.cpp
@@ -0,0 +1,39 @@
+// Copyright (c) 2023 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 <util/chaintype.h>
+
+#include <cassert>
+#include <optional>
+#include <string>
+
+std::string ChainTypeToString(ChainType chain)
+{
+    switch (chain) {
+    case ChainType::MAIN:
+        return "main";
+    case ChainType::TESTNET:
+        return "test";
+    case ChainType::SIGNET:
+        return "signet";
+    case ChainType::REGTEST:
+        return "regtest";
+    }
+    assert(false);
+}
+
+std::optional<ChainType> ChainTypeFromString(std::string_view chain)
+{
+    if (chain == "main") {
+        return ChainType::MAIN;
+    } else if (chain == "test") {
+        return ChainType::TESTNET;
+    } else if (chain == "signet") {
+        return ChainType::SIGNET;
+    } else if (chain == "regtest") {
+        return ChainType::REGTEST;
+    } else {
+        return std::nullopt;
+    }
+}
diff --git a/src/util/chaintype.h b/src/util/chaintype.h
new file mode 100644
index 0000000000..c73985df57
--- /dev/null
+++ b/src/util/chaintype.h
@@ -0,0 +1,22 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_CHAINTYPE_H
+#define BITCOIN_UTIL_CHAINTYPE_H
+
+#include <optional>
+#include <string>
+
+enum class ChainType {
+    MAIN,
+    TESTNET,
+    SIGNET,
+    REGTEST,
+};
+
+std::string ChainTypeToString(ChainType chain);
+
+std::optional<ChainType> ChainTypeFromString(std::string_view chain);
+
+#endif // BITCOIN_UTIL_CHAINTYPE_H
diff --git a/src/util/settings.cpp b/src/util/settings.cpp
index bb257c0584..db3d60046e 100644
--- a/src/util/settings.cpp
+++ b/src/util/settings.cpp
@@ -130,7 +130,7 @@ SettingsValue GetSetting(const Settings& settings,
     const std::string& name,
     bool ignore_default_section_config,
     bool ignore_nonpersistent,
-    bool get_chain_name)
+    bool get_chain_type)
 {
     SettingsValue result;
     bool done = false; // Done merging any more settings sources.
@@ -145,17 +145,17 @@ SettingsValue GetSetting(const Settings& settings,
         // assigned value instead of last. In general, later settings take
         // precedence over early settings, but for backwards compatibility in
         // the config file the precedence is reversed for all settings except
-        // chain name settings.
+        // chain type settings.
         const bool reverse_precedence =
             (source == Source::CONFIG_FILE_NETWORK_SECTION || source == Source::CONFIG_FILE_DEFAULT_SECTION) &&
-            !get_chain_name;
+            !get_chain_type;
 
         // Weird behavior preserved for backwards compatibility: Negated
         // -regtest and -testnet arguments which you would expect to override
         // values set in the configuration file are currently accepted but
         // silently ignored. It would be better to apply these just like other
         // negated values, or at least warn they are ignored.
-        const bool skip_negated_command_line = get_chain_name;
+        const bool skip_negated_command_line = get_chain_type;
 
         if (done) return;
 
diff --git a/src/util/settings.h b/src/util/settings.h
index 27e87a4751..bb1fe585e1 100644
--- a/src/util/settings.h
+++ b/src/util/settings.h
@@ -60,14 +60,14 @@ bool WriteSettings(const fs::path& path,
 //!                               command line). Only return settings in the
 //!                               read-only config and read-write settings
 //!                               files.
-//! @param get_chain_name - enable special backwards compatible behavior
-//!                         for GetChainName
+//! @param get_chain_type - enable special backwards compatible behavior
+//!                         for GetChainType
 SettingsValue GetSetting(const Settings& settings,
     const std::string& section,
     const std::string& name,
     bool ignore_default_section_config,
     bool ignore_nonpersistent,
-    bool get_chain_name);
+    bool get_chain_type);
 
 //! Get combined setting value similar to GetSetting(), except if setting was
 //! specified multiple times, return a list of all the values specified.