Merge #18067: wallet: Improve LegacyScriptPubKeyMan::CanProvide script recognition

a304a3632f0437f4d0f04589a2200e2da91624a7 Revert "Store p2sh scripts in AddAndGetDestinationForScript" (Russell Yanofsky)
eb7d8a5b07e89133a5fb465ad1b793362e7439f7 [test] check for addmultisigaddress regression (Sjors Provoost)
005f8a92ccb5bc10c8daa106d75e1c21390461d3 wallet: Improve LegacyScriptPubKeyMan::CanProvide script recognition (Russell Yanofsky)

Pull request description:

  Make `LegacyScriptPubKeyMan::CanProvide` method able to recognize p2sh scripts when the redeem script is present in the `mapScripts` map without the p2sh script also having to be added to the `mapScripts` map. This restores behavior prior to #17261, which I think broke backwards compatibility with old wallet files by no longer treating addresses created by `addmultisigaddress` calls before #17261 as solvable.

  The reason why tests didn't fail with the CanProvide implementation in #17261 is because of a workaround added in 4a7e43e8460127a40a7895519587399feff3b682 "Store p2sh scripts in AddAndGetDestinationForScript", which masked the problem for new `addmultisigaddress` RPC calls without fixing it for multisig addresses already created in old wallet files.

  This change adds a lot of comments and allows reverting commit 4a7e43e8460127a40a7895519587399feff3b682 "Store p2sh scripts in AddAndGetDestinationForScript", so the `AddAndGetDestinationForScript()` function, `CanProvide()` method, and `mapScripts` map should all be more comprehensible

ACKs for top commit:
  Sjors:
    re-ACK a304a3632f0437f4d0f04589a2200e2da91624a7 (rebase, slight text changes and my test)
  achow101:
    re-ACK a304a3632f0437f4d0f04589a2200e2da91624a7
  meshcollider:
    utACK a304a3632f0437f4d0f04589a2200e2da91624a7

Tree-SHA512: 03b625220c49684c376a8062d7646aeba0e5bfe043f977dc7dc357a6754627d594e070e4d458d12d2291888405d94c1dbe08c7787c318374cedd5755e724fb6e

1 files changed, 13 insertions, 1 deletions

diff --git a/test/functional/feature_backwards_compatibility.py b/test/functional/feature_backwards_compatibility.py
index 1ac10f971a..7a6e3df702 100755
--- a/test/functional/feature_backwards_compatibility.py
+++ b/test/functional/feature_backwards_compatibility.py
@@ -122,6 +122,9 @@ class BackwardsCompatibilityTest(BitcoinTestFramework):
         info = wallet.getwalletinfo()
         assert info['private_keys_enabled']
         assert info['keypoolsize'] > 0
+        # Use addmultisigaddress (see #18075)
+        address_18075 = wallet.addmultisigaddress(1, ["0296b538e853519c726a2c91e61ec11600ae1390813a627c66fb8be7947be63c52", "037211a824f55b505228e4c3d5194c1fcfaa15a456abdf37f9b9d97a4040afc073"], "", "legacy")["address"]
+        assert wallet.getaddressinfo(address_18075)["solvable"]
 
         # w1_v18: regular wallet, created with v0.18
         node_v18.createwallet(wallet_name="w1_v18")
@@ -319,7 +322,7 @@ class BackwardsCompatibilityTest(BitcoinTestFramework):
         hdkeypath = info["hdkeypath"]
         pubkey = info["pubkey"]
 
-        # Copy the wallet to the last Bitcoin Core version and open it:
+        # Copy the 0.17 wallet to the last Bitcoin Core version and open it:
         node_v17.unloadwallet("u1_v17")
         shutil.copytree(
             os.path.join(node_v17_wallets_dir, "u1_v17"),
@@ -331,5 +334,14 @@ class BackwardsCompatibilityTest(BitcoinTestFramework):
         descriptor = "wpkh([" + info["hdmasterfingerprint"] + hdkeypath[1:] + "]" + pubkey + ")"
         assert_equal(info["desc"], descsum_create(descriptor))
 
+        # Copy the 0.19 wallet to the last Bitcoin Core version and open it:
+        shutil.copytree(
+            os.path.join(node_v19_wallets_dir, "w1_v19"),
+            os.path.join(node_master_wallets_dir, "w1_v19")
+        )
+        node_master.loadwallet("w1_v19")
+        wallet = node_master.get_wallet_rpc("w1_v19")
+        assert wallet.getaddressinfo(address_18075)["solvable"]
+
 if __name__ == '__main__':
     BackwardsCompatibilityTest().main()