The internal script-to-descriptor inference procedure shouldn't return invalid
descriptors or ones that fail the string-to-descriptor parsing process. These
two procedures should always support seamless roundtrips.
This inlines `InferScript`/`InferDescriptor` to the actual descriptors
`ParseScript` logic for the multisig path, ensuring only valid descriptors are
produced.
Examples where this presents an issue:
1) Because the legacy wallet allowed the import of invalid scripts, the process
could end up inferring and storing an unparsable descriptor, which crashes
the software during any subsequent wallet load
2) The `decodescript()` RPC command currently return unusable multisig descriptors.
For example, providing a P2SH multisig redeem script with more than 520 bytes
results in a descriptor when it shouldn't due to its large size.
e.g. sh(addr(ADDR)) or sh(raw(HEX)) are invalid descriptors.
Making sh and wsh top level functions to return addr/raw descriptors when
the subscript inference fails.
The descriptor inference logic would previously always use a dummy
signing provider and would never analyze the witness script of a P2WSH
scriptPubKey.
Note even a valid Miniscript might not always be decodable from Script
without more contextual information (for instance the key preimage for a
pk_h).
Also remove the enumerations ("1)", "2)"...) from the test
cases as those potentially hinder maintainability; e.g. if a
new case in inserted in-between, all the remaining
enumerations would need to be adapted.
The previous diff touched most files in ./test/, so bump the headers to
avoid having to touch them again for a bump later.
-BEGIN VERIFY SCRIPT-
./contrib/devtools/copyright_header.py update ./test/
-END VERIFY SCRIPT-
