Merge #20156: build: Make sqlite support optional (compile-time)

bbb42a6896 RPC: createwallet: Nicer error message if descriptor wallet requested and sqlite support not compiled in (Luke Dashjr)
6608fec332 GUI: Create Wallet: Nicely disable descriptor wallet checkbox if sqlite support not compiled in (Luke Dashjr)
7b54d768e1 Make sqlite support optional (compile-time) (Luke Dashjr)

Pull request description:

  As a new requirement, sqlite support should be optional. This PR aims to be only minimum/blocker changes for 0.21.

  Potential follow-up PRs after this:
  * Make BDB support optional
  * Nicer error messages when user tries to load an unsupported wallet
  * Don't compile descriptor wallet code if sqlite disabled

ACKs for top commit:
  jonasschnelli:
    Tested ACK bbb42a6896
  achow101:
    ACK bbb42a6896
  Sjors:
    re-utACK bbb42a6896
  hebasto:
    ACK bbb42a6896, tested on Linux Mint 20 (x86_64, Qt 5.12.8).

Tree-SHA512: 500209dd1971310fab8ae51543343ce0ba91f088ccccff6109b4cc27547cd5532289dca6cb7dac2a7d7c59cdf3c8f5aacc31e9b0f912e38cea52ec26b97100bd

src/Makefile.am

@@ -356,7 +356,7 @@ endif
 
 # wallet: shared between bitcoind and bitcoin-qt, but only linked
 # when wallet enabled
-libbitcoin_wallet_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
+libbitcoin_wallet_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(SQLITE_CFLAGS)
 libbitcoin_wallet_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libbitcoin_wallet_a_SOURCES = \
   interfaces/wallet.cpp \
@@ -372,13 +372,16 @@ libbitcoin_wallet_a_SOURCES = \
   wallet/rpcwallet.cpp \
   wallet/salvage.cpp \
   wallet/scriptpubkeyman.cpp \
-  wallet/sqlite.cpp \
   wallet/wallet.cpp \
   wallet/walletdb.cpp \
   wallet/walletutil.cpp \
   wallet/coinselection.cpp \
   $(BITCOIN_CORE_H)
 
+if USE_SQLITE
+libbitcoin_wallet_a_SOURCES += wallet/sqlite.cpp
+endif
+
 libbitcoin_wallet_tool_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
 libbitcoin_wallet_tool_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libbitcoin_wallet_tool_a_SOURCES = \

src/qt/createwalletdialog.cpp

@@ -34,6 +34,12 @@ CreateWalletDialog::CreateWalletDialog(QWidget* parent) :
             ui->disable_privkeys_checkbox->setChecked(false);
         }
     });
+
+#ifndef USE_SQLITE
+    ui->descriptor_checkbox->setToolTip(tr("Compiled without sqlite support (required for descriptor wallets)"));
+    ui->descriptor_checkbox->setEnabled(false);
+    ui->descriptor_checkbox->setChecked(false);
+#endif
 }
 
 CreateWalletDialog::~CreateWalletDialog()

src/wallet/rpcwallet.cpp

@@ -2742,6 +2742,9 @@ static RPCHelpMan createwallet()
         flags |= WALLET_FLAG_AVOID_REUSE;
     }
     if (!request.params[5].isNull() && request.params[5].get_bool()) {
+#ifndef USE_SQLITE
+        throw JSONRPCError(RPC_WALLET_ERROR, "Compiled without sqlite support (required for descriptor wallets)");
+#endif
         flags |= WALLET_FLAG_DESCRIPTORS;
         warnings.emplace_back(Untranslated("Wallet is an experimental descriptor wallet"));
     }

src/wallet/walletdb.cpp

@@ -15,7 +15,9 @@
 #include <util/time.h>
 #include <util/translation.h>
 #include <wallet/bdb.h>
+#ifdef USE_SQLITE
 #include <wallet/sqlite.h>
+#endif
 #include <wallet/wallet.h>
 
 #include <atomic>
@@ -1012,6 +1014,7 @@ std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const Databas
         if (ExistsBerkeleyDatabase(path)) {
             format = DatabaseFormat::BERKELEY;
         }
+#ifdef USE_SQLITE
         if (ExistsSQLiteDatabase(path)) {
             if (format) {
                 error = Untranslated(strprintf("Failed to load database path '%s'. Data is in ambiguous format.", path.string()));
@@ -1020,6 +1023,7 @@ std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const Databas
             }
             format = DatabaseFormat::SQLITE;
         }
+#endif
     } else if (options.require_existing) {
         error = Untranslated(strprintf("Failed to load database path '%s'. Path does not exist.", path.string()));
         status = DatabaseStatus::FAILED_NOT_FOUND;
@@ -1048,9 +1052,13 @@ std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const Databas
     // Format is not set when a db doesn't already exist, so use the format specified by the options if it is set.
     if (!format && options.require_format) format = options.require_format;
 
+#ifdef USE_SQLITE
     if (format && format == DatabaseFormat::SQLITE) {
         return MakeSQLiteDatabase(path, options, status, error);
     }
+#else
+    assert(format != DatabaseFormat::SQLITE);
+#endif
 
     return MakeBerkeleyDatabase(path, options, status, error);
 }

src/wallet/walletutil.cpp

@@ -8,7 +8,11 @@
 #include <util/system.h>
 
 bool ExistsBerkeleyDatabase(const fs::path& path);
+#ifdef USE_SQLITE
 bool ExistsSQLiteDatabase(const fs::path& path);
+#else
+#   define ExistsSQLiteDatabase(path)  (false)
+#endif
 
 fs::path GetWalletDir()
 {