Merge bitcoin/bitcoin#24148: Miniscript support in Output Descriptors

ffc79b8e492c6dd1352e528fd82e45d8d25eaa04 qa: functional test Miniscript watchonly support (Antoine Poinsot)
bfb036756ad6e187fd6d3abfefe5804bb54a5c71 Miniscript support in output descriptors (Antoine Poinsot)
4a082887bee76a96deada5dbd7f991c23b301c54 qa: better error reporting on descriptor parsing error (Antoine Poinsot)
d25d58bf5f301d3bb8683bd67c8847a4957d8e97 miniscript: add a helper to find the first insane sub with no child (Antoine Poinsot)
c38c7c5817b7e73cf0f788855c4aba59c287b0ad miniscript: don't check for top level validity at parsing time (Antoine Poinsot)

Pull request description:

  This adds Miniscript support for Output Descriptors without any signing logic (yet). See the OP of #24147 for a description of Miniscript and a rationale of having it in Bitcoin Core.
  On its own, this PR adds "watchonly" support for Miniscript descriptors in the descriptor wallet. A follow-up adds signing support.

  A minified corpus of Miniscript Descriptors for the `descriptor_parse` fuzz target is available at https://github.com/bitcoin-core/qa-assets/pull/92.
  The Miniscript descriptors used in the unit tests here and in #24149 were cross-tested against the Rust implementation at https://github.com/rust-bitcoin/rust-miniscript.

  This PR contains code and insights from Pieter Wuille.

ACKs for top commit:
  Sjors:
    re-utACK ffc79b8e492c6dd1352e528fd82e45d8d25eaa04
  achow101:
    ACK ffc79b8e492c6dd1352e528fd82e45d8d25eaa04
  w0xlt:
    reACK https://github.com/bitcoin/bitcoin/pull/24148/commits/ffc79b8e492c6dd1352e528fd82e45d8d25eaa04

Tree-SHA512: 02d919d38bb626d3c557eca3680ce71117739fa161b7a92cfdb6c9c432ed88870b1ed127ba24248574c40c7428217d7e9bdd986fd8cd7c51fae8c776e1271fb9

2 files changed, 41 insertions, 6 deletions

diff --git a/src/test/descriptor_tests.cpp b/src/test/descriptor_tests.cpp
index 63c86a896d..a8c666079d 100644
--- a/src/test/descriptor_tests.cpp
+++ b/src/test/descriptor_tests.cpp
@@ -141,14 +141,13 @@ void DoCheck(const std::string& prv, const std::string& pub, const std::string&
     } else {
         parse_priv = Parse(prv, keys_priv, error);
     }
+    BOOST_CHECK_MESSAGE(parse_priv, error);
     if (replace_apostrophe_with_h_in_pub) {
         parse_pub = Parse(UseHInsteadOfApostrophe(pub), keys_pub, error);
     } else {
         parse_pub = Parse(pub, keys_pub, error);
     }
-
-    BOOST_CHECK(parse_priv);
-    BOOST_CHECK(parse_pub);
+    BOOST_CHECK_MESSAGE(parse_pub, error);
 
     // Check that the correct OutputType is inferred
     BOOST_CHECK(parse_priv->GetOutputType() == type);
@@ -161,8 +160,8 @@ void DoCheck(const std::string& prv, const std::string& pub, const std::string&
     // Check that both versions serialize back to the public version.
     std::string pub1 = parse_priv->ToString();
     std::string pub2 = parse_pub->ToString();
-    BOOST_CHECK(EqualDescriptor(pub, pub1));
-    BOOST_CHECK(EqualDescriptor(pub, pub2));
+    BOOST_CHECK_MESSAGE(EqualDescriptor(pub, pub1), "Private ser: " + pub1 + " Public desc: " + pub);
+    BOOST_CHECK_MESSAGE(EqualDescriptor(pub, pub2), "Public ser: " + pub2 + " Public desc: " + pub);
 
     // Check that both can be serialized with private key back to the private version, but not without private key.
     if (!(flags & MISSING_PRIVKEYS)) {
@@ -486,6 +485,29 @@ Check("sh(wsh(multi(20,KzoAz5CanayRKex3fSLQ2BwJpN7U52gZvxMyk78nDMHuqrUxuSJy,KwGN
     }
     nonminimalmultisig << std::vector<unsigned char>{4} << OP_CHECKMULTISIG;
     CheckInferRaw(nonminimalmultisig);
+
+    // Miniscript tests
+
+    // Invalid checksum
+    CheckUnparsable("wsh(and_v(vc:andor(pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),pk_k(Kx9HCDjGiwFcgVNhTrS5z5NeZdD6veeam61eDxLDCkGWujvL4Gnn),and_v(v:older(1),pk_k(L4o2kDvXXDRH2VS9uBnouScLduWt4dZnM25se7kvEjJeQ285en2A))),after(10)))#abcdef12", "wsh(and_v(vc:andor(pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10)))#abcdef12", "Provided checksum 'abcdef12' does not match computed checksum 'tyzp6a7p'");
+    // Only p2wsh context is valid
+    CheckUnparsable("sh(and_v(vc:andor(pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),pk_k(Kx9HCDjGiwFcgVNhTrS5z5NeZdD6veeam61eDxLDCkGWujvL4Gnn),and_v(v:older(1),pk_k(L4o2kDvXXDRH2VS9uBnouScLduWt4dZnM25se7kvEjJeQ285en2A))),after(10)))", "sh(and_v(vc:andor(pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10)))", "Miniscript expressions can only be used in wsh");
+    CheckUnparsable("tr(and_v(vc:andor(pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),pk_k(Kx9HCDjGiwFcgVNhTrS5z5NeZdD6veeam61eDxLDCkGWujvL4Gnn),and_v(v:older(1),pk_k(L4o2kDvXXDRH2VS9uBnouScLduWt4dZnM25se7kvEjJeQ285en2A))),after(10)))", "tr(and_v(vc:andor(pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10)))", "tr(): key 'and_v(vc:andor(pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10))' is not valid");
+    CheckUnparsable("raw(and_v(vc:andor(pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),pk_k(Kx9HCDjGiwFcgVNhTrS5z5NeZdD6veeam61eDxLDCkGWujvL4Gnn),and_v(v:older(1),pk_k(L4o2kDvXXDRH2VS9uBnouScLduWt4dZnM25se7kvEjJeQ285en2A))),after(10)))", "sh(and_v(vc:andor(pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10)))", "Miniscript expressions can only be used in wsh");
+    CheckUnparsable("", "tr(034D2224bbbbbbbbbbcbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb40,{{{{{{{{{{{{{{{{{{{{{{multi(1,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc/967808'/9,xprvA1RpRA33e1JQ7ifknakTFNpgXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc/968/2/5/8/5/2/5/58/58/2/5/5/5/58/588/2/6/8/5/2/8/2/5/8/2/58/2/5/8/5/2/8/5/8/3/4/5/58/55/2/5/58/58/2/5/5/5/8/5/2/8/5/85/2/8/2/5/8/5/2/5/58/58/2/5/58/58/588/2/58/2/8/5/8/5/4/5/585/2/5/58/58/2/5/5/58/588/2/58/2/5/8/5/2/8/2/5/8/5/5/58/588/2/6/8/5/2/8/2/5/8/5/2/5/58/58/2/5/58/58/2/0/8/5/2/8/5/8/5/4/5/58/588/2/6/8/5/2/8/2/5/8/5/2/5/58/58/2/5/58/58/588/2/58/2/5/8/5/8/24/5/58/52/5/8/5/2/8/24/5/58/588/246/8/5/2/8/2/5/8/5/2/5/58/58/2/5/5/5/58/588/2/6/8/5/2/8/2/5/8/2/58/2/5/8/5/2/8/5/8/5/4/5/58/55/58/2/5/8/55/2/5/8/58/555/58/2/5/8/4//2/5/58/5w/2/5/8/5/2/4/5/58/5558'/2/5/58/58/2/5/5/58/588/2/58/2/5/8/5/2/8/2/5/8/5/5/8/58/2/5/58/58/2/5/8/9/588/2/58/2/5/8/5/2/8/5/8/5/4/5/58/588/2/6/8/5/2/8/2/5/8/5/2/5/58/58/2/5/5/58/588/2/58/2/5/8/5/2/82/5/8/5/5/58/52/6/8/5/2/8/{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{}{{{{{{{{{DDD2/5/8/5/2/5/58/58/2/5/58/58/588/2/58/2/8/5/8/5/4/5/58/588/2/6/8/5/2/8/2/5/8588/246/8/5/2DLDDDDDDDbbD3DDDD/8/2/5/8/5/2/5/58/58/2/5/5/5/58/588/2/6/8/5/2/8/2/5/8/2/58/2/5/8/5/2/8/5/8/3/4/5/58/55/2/5/58/58/2/5/5/5/8/5/2/8/5/85/2/8/2/5/8D)/5/2/5/58/58/2/5/58/58/58/588/2/58/2/5/8/5/25/58/58/2/5/58/58/2/5/8/9/588/2/58/2/6780,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFW/8/5/2/5/58678008')", "'multi(1,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc/967808'/9,xprvA1RpRA33e1JQ7ifknakTFNpgXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc/968/2/5/8/5/2/5/58/58/2/5/5/5/58/588/2/6/8/5/2/8/2/5/8/2/58/2/5/8/5/2/8/5/8/3/4/5/58/55/2/5/58/58/2/5/5/5/8/5/2/8/5/85/2/8/2/5/8/5/2/5/58/58/2/5/58/58/588/2/58/2/8/5/8/5/4/5/585/2/5/58/58/2/5/5/58/588/2/58/2/5/8/5/2/8/2/5/8/5/5/58/588/2/6/8/5/2/8/2/5/8/5/2/5/58/58/2/5/58/58/2/0/8/5/2/8/5/8/5/4/5/58/588/2/6/8/5/2/8/2/5/8/5/2/5/58/58/2/5/58/58/588/2/58/2/5/8/5/8/24/5/58/52/5/8/5/2/8/24/5/58/588/246/8/5/2/8/2/5/8/5/2/5/58/58/2/5/5/5/58/588/2/6/8/5/2/8/2/5/8/2/58/2/5/8/5/2/8/5/8/5/4/5/58/55/58/2/5/8/55/2/5/8/58/555/58/2/5/8/4//2/5/58/5w/2/5/8/5/2/4/5/58/5558'/2/5/58/58/2/5/5/58/588/2/58/2/5/8/5/2/8/2/5/8/5/5/8/58/2/5/58/58/2/5/8/9/588/2/58/2/5/8/5/2/8/5/8/5/4/5/58/588/2/6/8/5/2/8/2/5/8/5/2/5/58/58/2/5/5/58/588/2/58/2/5/8/5/2/82/5/8/5/5/58/52/6/8/5/2/8/{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{}{{{{{{{{{DDD2/5/8/5/2/5/58/58/2/5/58/58/588/2/58/2/8/5/8/5/4/5/58/588/2/6/8/5/2/8/2/5/8588/246/8/5/2DLDDDDDDDbbD3DDDD/8/2/5/8/5/2/5/58/58/2/5/5/5/58/588/2/6/8/5/2/8/2/5/8/2/58/2/5/8/5/2/8/5/8/3/4/5/58/55/2/5/58/58/2/5/5/5/8/5/2/8/5/85/2/8/2/5/8D)/5/2/5/58/58/2/5/58/58/58/588/2/58/2/5/8/5/25/58/58/2/5/58/58/2/5/8/9/588/2/58/2/6780,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFW/8/5/2/5/58678008'' is not a valid descriptor function");
+    // Insane at top level
+    CheckUnparsable("wsh(and_b(vc:andor(pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),pk_k(Kx9HCDjGiwFcgVNhTrS5z5NeZdD6veeam61eDxLDCkGWujvL4Gnn),and_v(v:older(1),pk_k(L4o2kDvXXDRH2VS9uBnouScLduWt4dZnM25se7kvEjJeQ285en2A))),after(10)))", "wsh(and_b(vc:andor(pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10)))", "and_b(vc:andor(pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10)) is invalid");
+    // Invalid sub
+    CheckUnparsable("wsh(and_v(vc:andor(v:pk_k(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),pk_k(Kx9HCDjGiwFcgVNhTrS5z5NeZdD6veeam61eDxLDCkGWujvL4Gnn),and_v(v:older(1),pk_k(L4o2kDvXXDRH2VS9uBnouScLduWt4dZnM25se7kvEjJeQ285en2A))),after(10)))", "wsh(and_v(vc:andor(v:pk_k(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),pk_k(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0),and_v(v:older(1),pk_k(02aa27e5eb2c185e87cd1dbc3e0efc9cb1175235e0259df1713424941c3cb40402))),after(10)))", "v:pk_k(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204) is invalid");
+    // Insane subs
+    CheckUnparsable("wsh(or_i(older(1),pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd)))", "wsh(or_i(older(1),pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)))", "or_i(older(1),pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)) is not sane: witnesses without signature exist");
+    CheckUnparsable("wsh(or_b(sha256(cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),s:pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)))", "wsh(or_b(sha256(cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),s:pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)))", "or_b(sha256(cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),s:pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)) is not sane: malleable witnesses exist");
+    CheckUnparsable("wsh(and_b(and_b(older(1),a:older(100000000)),s:pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd)))", "wsh(and_b(and_b(older(1),a:older(100000000)),s:pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)))", "and_b(older(1),a:older(100000000)) is not sane: contains mixes of timelocks expressed in blocks and seconds");
+    CheckUnparsable("wsh(and_b(or_b(pkh(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),s:pk(Kx9HCDjGiwFcgVNhTrS5z5NeZdD6veeam61eDxLDCkGWujvL4Gnn)),s:pk(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd)))", "wsh(and_b(or_b(pkh(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),s:pk(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0)),s:pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)))", "and_b(or_b(pkh(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),s:pk(032707170c71d8f75e4ca4e3fce870b9409dcaf12b051d3bcadff74747fa7619c0)),s:pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204)) is not sane: contains duplicate public keys");
+    // Valid with extended keys.
+    Check("wsh(and_v(v:ripemd160(095ff41131e5946f3c85f79e44adbcf8e27e080e),multi(1,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0)))", "wsh(and_v(v:ripemd160(095ff41131e5946f3c85f79e44adbcf8e27e080e),multi(1,xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0)))", "wsh(and_v(v:ripemd160(095ff41131e5946f3c85f79e44adbcf8e27e080e),multi(1,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0)))", "wsh(and_v(v:ripemd160(095ff41131e5946f3c85f79e44adbcf8e27e080e),multi(1,xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0)))", UNSOLVABLE, {{"0020acf425291b98a1d7e0d4690139442abc289175be32ef1f75945e339924246d73"}}, OutputType::BECH32, {{},{0}});
+    // Valid under sh(wsh()) and with a mix of xpubs and raw keys
+    Check("sh(wsh(thresh(1,pkh(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),a:and_n(multi(1,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0),n:older(2)))))", "sh(wsh(thresh(1,pkh(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),a:and_n(multi(1,xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0),n:older(2)))))", "sh(wsh(thresh(1,pkh(L4gM1FBdyHNpkzsFh9ipnofLhpZRp2mwobpeULy1a6dBTvw8Ywtd),a:and_n(multi(1,xprvA1RpRA33e1JQ7ifknakTFpgNXPmW2YvmhqLQYMmrj4xJXXWYpDPS3xz7iAxn8L39njGVyuoseXzU6rcxFLJ8HFsTjSyQbLYnMpCqE2VbFWc,xprv9uPDJpEQgRQfDcW7BkF7eTya6RPxXeJCqCJGHuCJ4GiRVLzkTXBAJMu2qaMWPrS7AANYqdq6vcBcBUdJCVVFceUvJFjaPdGZ2y9WACViL4L/0),n:older(2)))))", "sh(wsh(thresh(1,pkh(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204),a:and_n(multi(1,xpub6ERApfZwUNrhLCkDtcHTcxd75RbzS1ed54G1LkBUHQVHQKqhMkhgbmJbZRkrgZw4koxb5JaHWkY4ALHY2grBGRjaDMzQLcgJvLJuZZvRcEL,xpub68NZiKmJWnxxS6aaHmn81bvJeTESw724CRDs6HbuccFQN9Ku14VQrADWgqbhhTHBaohPX4CjNLf9fq9MYo6oDaPPLPxSb7gwQN3ih19Zm4Y/0),n:older(2)))))", UNSOLVABLE | MIXED_PUBKEYS, {{"a914767e9119ff3b3ac0cb6dcfe21de1842ccf85f1c487"}}, OutputType::P2SH_SEGWIT, {{},{0}});
 }
 
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/miniscript_tests.cpp b/src/test/miniscript_tests.cpp
index 3877fea907..bc5c49ef63 100644
--- a/src/test/miniscript_tests.cpp
+++ b/src/test/miniscript_tests.cpp
@@ -111,6 +111,10 @@ struct KeyConverter {
         assert(it != g_testdata->pkmap.end());
         return it->second;
     }
+
+    std::optional<std::string> ToString(const Key& key) const {
+        return HexStr(ToPKBytes(key));
+    }
 };
 
 //! Singleton instance of KeyConverter.
@@ -276,7 +280,7 @@ BOOST_AUTO_TEST_CASE(fixed_tests)
     // (for now) have 'd:' be 'u'. This tests we can't use a 'd:' wrapper for a thresh, which requires
     // its subs to all be 'u' (taken from https://github.com/rust-bitcoin/rust-miniscript/discussions/341).
     const auto ms_minimalif = miniscript::FromString("thresh(3,c:pk_k(03d30199d74fb5a22d47b6e054e2f378cedacffcb89904a61d75d0dbd407143e65),sc:pk_k(03fff97bd5755eeea420453a14355235d382f6472f8568a18b2f057a1460297556),sc:pk_k(0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798),sdv:older(32))", CONVERTER);
-    BOOST_CHECK(!ms_minimalif);
+    BOOST_CHECK(ms_minimalif && !ms_minimalif->IsValid());
     // A Miniscript with duplicate keys is not sane
     const auto ms_dup1 = miniscript::FromString("and_v(v:pk(03d30199d74fb5a22d47b6e054e2f378cedacffcb89904a61d75d0dbd407143e65),pk(03d30199d74fb5a22d47b6e054e2f378cedacffcb89904a61d75d0dbd407143e65))", CONVERTER);
     BOOST_CHECK(ms_dup1);
@@ -290,6 +294,15 @@ BOOST_AUTO_TEST_CASE(fixed_tests)
     // Same when the duplicates are on different levels in the tree
     const auto ms_dup4 = miniscript::FromString("thresh(2,pkh(03d30199d74fb5a22d47b6e054e2f378cedacffcb89904a61d75d0dbd407143e65),s:pk(03fff97bd5755eeea420453a14355235d382f6472f8568a18b2f057a1460297556),a:and_b(dv:older(1),s:pk(03d30199d74fb5a22d47b6e054e2f378cedacffcb89904a61d75d0dbd407143e65)))", CONVERTER);
     BOOST_CHECK(ms_dup4 && !ms_dup4->IsSane() && !ms_dup4->CheckDuplicateKey());
+    // Test we find the first insane sub closer to be a leaf node. This fragment is insane for two reasons:
+    // 1. It can be spent without a signature
+    // 2. It contains timelock mixes
+    // We'll report the timelock mix error, as it's "deeper" (closer to be a leaf node) than the "no 's' property"
+    // error is.
+    const auto ms_ins = miniscript::FromString("or_i(and_b(after(1),a:after(1000000000)),pk(03cdabb7f2dce7bfbd8a0b9570c6fd1e712e5d64045e9d6b517b3d5072251dc204))", CONVERTER);
+    BOOST_CHECK(ms_ins && ms_ins->IsValid() && !ms_ins->IsSane());
+    const auto insane_sub = ms_ins->FindInsaneSub();
+    BOOST_CHECK(insane_sub && *insane_sub->ToString(CONVERTER) == "and_b(after(1),a:after(1000000000))");
 
     // Timelock tests
     Test("after(100)", "?", TESTMODE_VALID | TESTMODE_NONMAL); // only heightlock