Merge bitcoin/bitcoin#19602: wallet: Migrate legacy wallets to descriptor wallets

53e7ed075c49f853cc845afc7b2f058cabad0cb0 doc: Release notes and other docs for migration (Andrew Chow)
9c44bfe244f35f08ba576d8b979a90dcd68d2c77 Test migratewallet (Andrew Chow)
0b26e7cdf2659fd8b54d21fd2bd749f9f3e87af8 descriptors: addr() and raw() should return false for ToPrivateString (Andrew Chow)
31764c3f872f4f01b48d50585f86e97c41554954 Add migratewallet RPC (Andrew Chow)
0bf7b38bff422e7413bcd3dc0abe2568dd918ddc Implement MigrateLegacyToDescriptor (Andrew Chow)
e7b16f925ae5b117e8b74ce814b63e19b19b50f4 Implement MigrateToSQLite (Andrew Chow)
5b62f095e790a0d4e2a70ece89465b64fc68358a wallet: Refactor SetupDescSPKMs to take CExtKey (Andrew Chow)
22401f17e026ead4bc3fe96967eec56a719a4f75 Implement LegacyScriptPubKeyMan::DeleteRecords (Andrew Chow)
35f428fae68ad974abdce0fa905148f620a9443c Implement LegacyScriptPubKeyMan::MigrateToDescriptor (Andrew Chow)
ea1ab390e4dac128e3a37d4884528c3f4128ed83 scriptpubkeyman: Implement GetScriptPubKeys in Legacy (Andrew Chow)
e664af29760527e75cd7e290be5f102b6d29ebee Apply label to all scriptPubKeys of imported combo() (Andrew Chow)

Pull request description:

  This PR adds a new `migratewallet` RPC which migrates a legacy wallet to a descriptor wallet. Migrated wallets will need a new backup. If a wallet has watchonly stuff in it, a new watchonly descriptor wallet will be created containing those watchonly things. The related transactions, labels, and descriptors for those watchonly things will be removed from the original wallet. Migrated wallets will not have any of the legacy things be available for fetching from `getnewaddress` or `getrawchangeaddress`. Wallets that have private keys enabled will have newly generated descriptors. Wallets with private keys disabled will not have any active `ScriptPubKeyMan`s.

  For the basic HD wallet case of just generated keys, in addition to the standard descriptor wallet descriptors using the master key derived from the pre-existing hd seed, the migration will also create 3 descriptors for each HD chain in: a ranged combo external, a ranged combo internal, and a single key combo for the seed (the seed is a valid key that we can receive coins at!). The migrated wallet will then have newly generated descriptors as the active `ScriptPubKeyMan`s. This is equivalent to creating a new descriptor wallet and importing the 3 descriptors for each HD chain. For wallets containing non-HD keys, each key will have its own combo descriptor.

  There are also tests.

ACKs for top commit:
  Sjors:
    tACK 53e7ed075c49f853cc845afc7b2f058cabad0cb0
  w0xlt:
    reACK https://github.com/bitcoin/bitcoin/commit/53e7ed075c49f853cc845afc7b2f058cabad0cb0

Tree-SHA512: c0c003694ca2e17064922d08e8464278d314e970efb7df874b4fe04ec5d124c7206409ca701c65c099d17779ab2136ae63f1da2a9dba39b45f6d62cf93b5c60a

2 files changed, 35 insertions, 1 deletions

diff --git a/doc/managing-wallets.md b/doc/managing-wallets.md
index 6c1e13c503..366d7ec54b 100644
--- a/doc/managing-wallets.md
+++ b/doc/managing-wallets.md
@@ -120,4 +120,29 @@ After that, `getwalletinfo` can be used to check if the wallet has been fully re
 $ bitcoin-cli -rpcwallet="restored-wallet" getwalletinfo
 ```
 
-The restored wallet can also be loaded in the GUI via `File` ->`Open wallet`.
\ No newline at end of file
+The restored wallet can also be loaded in the GUI via `File` ->`Open wallet`.
+
+## Migrating Legacy Wallets to Descriptor Wallets
+
+Legacy wallets (traditional non-descriptor wallets) can be migrated to become Descriptor wallets
+through the use of the `migratewallet` RPC. Migrated wallets will have all of their addresses and private keys added to
+a newly created Descriptor wallet that has the same name as the original wallet. Because Descriptor
+wallets do not support having private keys and watch-only scripts, there may be up to two
+additional wallets created after migration. In addition to a descriptor wallet of the same name,
+there may also be a wallet named `<name>_watchonly` and `<name>_solvables`. `<name>_watchonly`
+contains all of the watchonly scripts. `<name>_solvables` contains any scripts which the wallet
+knows but is not watching the corresponding P2(W)SH scripts.
+
+Migrated wallets will also generate new addresses differently. While the same BIP 32 seed will be
+used, the BIP 44, 49, 84, and 86 standard derivation paths will be used. After migrating, a new
+backup of the wallet(s) will need to be created.
+
+Given that there is an extremely large number of possible configurations for the scripts that
+Legacy wallets can know about, be watching for, and be able to sign for, `migratewallet` only
+makes a best effort attempt to capture all of these things into Descriptor wallets. There may be
+unforeseen configurations which result in some scripts being excluded. If a migration fails
+unexpectedly or otherwise misses any scripts, please create an issue on GitHub. A backup of the
+original wallet can be found in the wallet directory with the name `<name>-<timestamp>.legacy.bak`.
+
+The backup can be restored using the `restorewallet` command as discussed in the
+[Restoring the Wallet From a Backup](#16-restoring-the-wallet-from-a-backup) section
diff --git a/doc/release-notes-19602.md b/doc/release-notes-19602.md
new file mode 100644
index 0000000000..61d6aa8ca9
--- /dev/null
+++ b/doc/release-notes-19602.md
@@ -0,0 +1,9 @@
+Wallet
+======
+
+Migrating Legacy Wallets to Descriptor Wallets
+---------------------------------------------
+
+An experimental RPC `migratewallet` has been added to migrate Legacy (non-descriptor) wallets to
+Descriptor wallets. More information about the migration process is available in the
+[documentation](https://github.com/bitcoin/bitcoin/blob/master/doc/managing-wallets.md#migrating-legacy-wallets-to-descriptor-wallets).