Merge #16542: Return more specific errors about invalid descriptors

787c9ec Additional tests for other failure cases (Andrew Chow)
6e1ae58 Check error messages in descriptor tests (Andrew Chow)
625534d Give more errors for specific failure conditions (Andrew Chow)
c325f61 Return an error from descriptor Parse that gives more information about what failed (Andrew Chow)

Pull request description:

  Because it's nigh impossible to figure out what is wrong with a descriptor otherwise.

ACKs for top commit:
  Sjors:
    ACK 787c9ec
  meshcollider:
    Code review ACK 787c9ec

Tree-SHA512: 07c5deff127fd65507b96df2e4608b4f918e0cbd20b3b45b9ab5a05c2985a6efa9832079cf1e7f504305bfbb861019e93b96cc1574dd63b2ff0756b5928ece20

Author: meshcollider

src/rpc/misc.cpp

@@ -150,9 +150,10 @@ UniValue getdescriptorinfo(const JSONRPCRequest& request)
     RPCTypeCheck(request.params, {UniValue::VSTR});
 
     FlatSigningProvider provider;
-    auto desc = Parse(request.params[0].get_str(), provider);
+    std::string error;
+    auto desc = Parse(request.params[0].get_str(), provider, error);
     if (!desc) {
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Invalid descriptor"));
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
     }
 
     UniValue result(UniValue::VOBJ);
@@ -199,9 +200,10 @@ UniValue deriveaddresses(const JSONRPCRequest& request)
     }
 
     FlatSigningProvider key_provider;
-    auto desc = Parse(desc_str, key_provider, /* require_checksum = */ true);
+    std::string error;
+    auto desc = Parse(desc_str, key_provider, error, /* require_checksum = */ true);
     if (!desc) {
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Invalid descriptor"));
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
     }
 
     if (!desc->IsRange() && request.params.size() > 1) {

src/rpc/util.cpp

@@ -717,9 +717,10 @@ std::vector<CScript> EvalDescriptorStringOrObject(const UniValue& scanobject, Fl
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Scan object needs to be either a string or an object");
     }
 
-    auto desc = Parse(desc_str, provider);
+    std::string error;
+    auto desc = Parse(desc_str, provider, error);
     if (!desc) {
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Invalid descriptor '%s'", desc_str));
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
     }
     if (!desc->IsRange()) {
         range.first = 0;

src/script/descriptor.cpp

@@ -79,7 +79,7 @@ struct Descriptor {
  * If a parse error occurs, or the checksum is missing/invalid, or anything
  * else is wrong, nullptr is returned.
  */
-std::unique_ptr<Descriptor> Parse(const std::string& descriptor, FlatSigningProvider& out, bool require_checksum = false);
+std::unique_ptr<Descriptor> Parse(const std::string& descriptor, FlatSigningProvider& out, std::string& error, bool require_checksum = false);
 
 /** Get the checksum for a descriptor.
  *

src/script/descriptor.h

@@ -1098,9 +1098,10 @@ static UniValue ProcessImportDescriptor(ImportData& import_data, std::map<CKeyID
 
     const std::string& descriptor = data["desc"].get_str();
     FlatSigningProvider keys;
-    auto parsed_desc = Parse(descriptor, keys, /* require_checksum = */ true);
+    std::string error;
+    auto parsed_desc = Parse(descriptor, keys, error, /* require_checksum = */ true);
     if (!parsed_desc) {
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Descriptor is invalid");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
     }
 
     have_solving_data = parsed_desc->IsSolvable();

src/test/descriptor_tests.cpp

@@ -13,14 +13,14 @@ def set_test_params(self):
         self.supports_cli = 1
 
     def run_test(self):
-        assert_raises_rpc_error(-5, "Invalid descriptor", self.nodes[0].deriveaddresses, "a")
+        assert_raises_rpc_error(-5, "Missing checksum", self.nodes[0].deriveaddresses, "a")
 
         descriptor = "wpkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/0)#t6wfjs64"
         address = "bcrt1qjqmxmkpmxt80xz4y3746zgt0q3u3ferr34acd5"
         assert_equal(self.nodes[0].deriveaddresses(descriptor), [address])
 
         descriptor = descriptor[:-9]
-        assert_raises_rpc_error(-5, "Invalid descriptor", self.nodes[0].deriveaddresses, descriptor)
+        assert_raises_rpc_error(-5, "Missing checksum", self.nodes[0].deriveaddresses, descriptor)
 
         descriptor_pubkey = "wpkh(tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/0)#s9ga3alw"
         address = "bcrt1qjqmxmkpmxt80xz4y3746zgt0q3u3ferr34acd5"

src/wallet/rpcdump.cpp

@@ -552,7 +552,7 @@ def run_test(self):
                                "keys": [key.privkey]},
                               success=False,
                               error_code=-5,
-                              error_message="Descriptor is invalid")
+                              error_message="Missing checksum")
 
         # Test importing of a P2SH-P2WPKH address via descriptor + private key
         key = get_key(self.nodes[0])