feat: add validation for zero confirmation block sync (#6237)

Description
---
Added validation checks to ensure an input in a block that is also an
output in the same block will be accepted when syncing blocks.

Motivation and Context
---
Blocks with zero confirmation inputs and outputs could not be synced
with block sync.

Previous for block `#3316` and input/output
`00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425`:
```rust
2024-03-26 11:40:08.989607400 [c::cs::lmdb_db::lmdb_db] DEBUG Fetch output: 00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425
2024-03-26 11:40:08.989617600 [c::cs::lmdb_db::lmdb_db] DEBUG Fetch output: 00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425 NOT found in index
2024-03-26 11:40:08.991003900 [c::cs::lmdb_db::lmdb_db] TRACE [apply_db_transaction] WriteOperation: Delete orphan with hash: 8a0ac6b1581eedffffcde3b05613b5ec525cd0575cb5a93a5f2bcbe0917957f6
2024-03-26 11:40:08.991035700 [c::cs::lmdb_db::lmdb_db] DEBUG delete_orphan: request to delete orphan block 8a0ac6b1581eedffffcde3b05613b5ec525cd0575cb5a93a5f2bcbe0917957f6 that was not found.
2024-03-26 11:40:08.991047800 [c::cs::lmdb_db::lmdb_db] TRACE [apply_db_transaction] WriteOperation: Insert bad block #3316 8a0ac6b1581eedffffcde3b05613b5ec525cd0575cb5a93a5f2bcbe0917957f6
2024-03-26 11:40:08.991068000 [c::cs::lmdb_db::lmdb_db] DEBUG Cleaned out 0 stale bad blocks
2024-03-26 11:40:08.993916100 [c::cs::lmdb_db::lmdb_db] TRACE Database completed 2 operation(s) in 3ms
2024-03-26 11:40:08.996400500 [c::bn::block_sync] WARN  Block validation failed: Contains an unknown input
2024-03-26 11:40:08.997329500 [c::bn::block_sync] WARN  Block validation failed: Contains an unknown input
2024-03-26 11:40:08.997882300 [c::bn::sync] DEBUG Sync peer 7dcc333714f9b31ebda93edec1 removed from the sync peer list because Contains an unknown input
2024-03-26 11:40:08.997900900 [c::bn::sync] WARN  Banned sync peer 7dcc333714f9b31ebda93edec1 for 7200s because Contains an unknown input
2024-03-26 11:40:08.997914500 [c::bn::block_sync] WARN  Block sync failed: No more sync peers available: Block sync failed
```
This PR:
```rust
2024-03-26 13:57:51.006006700 [c::cs::lmdb_db::lmdb_db] DEBUG Fetch output: 00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425
2024-03-26 13:57:51.006025600 [c::cs::lmdb_db::lmdb_db] DEBUG Fetch output: 00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425 NOT found in index
2024-03-26 13:57:51.008880000 [c::cs::lmdb_db::lmdb_db] DEBUG Fetch output: 00f6bce621663a88a0dd0a156d3d4adabb7fc7f38077052f54da5297c52def10
2024-03-26 13:57:51.008910600 [c::cs::lmdb_db::lmdb_db] DEBUG Fetch output: 00f6bce621663a88a0dd0a156d3d4adabb7fc7f38077052f54da5297c52def10 Found (0ee73f94629ecacd0d9118d5852e42831b8f71a0ce56e2b18cc20506b1d3135c00f6bce621663a88a0dd0a156d3d4adabb7fc7f38077052f54da5297c52def10)
...
2024-03-26 13:57:51.463387100 [c::cs::lmdb_db::lmdb_db] DEBUG Fetch output: 00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425 NOT found in index
2024-03-26 13:57:51.463541300 [c::val::helpers] WARN  Input: (6c8f19486e43c051fb9f308d5eaa6b06a726d0cf1c17c713453d904faf405c56, 00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425) does not exist in the database yet
...
2024-03-26 13:57:55.618675800 [c::cs::lmdb_db::lmdb_db] TRACE Inserting output (`6c8f19486e43c051fb9f308d5eaa6b06a726d0cf1c17c713453d904faf405c56`, `00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425`)
2024-03-26 13:57:55.618713200 [c::cs::lmdb_db::lmdb] TRACE Inserted 72 bytes with key '00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425' into 'txos_hash_to_index_db'
2024-03-26 13:57:55.618729500 [c::cs::lmdb_db::lmdb] TRACE Inserted 1121 bytes with key '8a0ac6b1581eedffffcde3b05613b5ec525cd0575cb5a93a5f2bcbe0917957f600eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425' into 'utxos_db'
2024-03-26 13:57:55.745300700 [c::cs::lmdb_db::lmdb_db] TRACE Inserting input (`6c8f19486e43c051fb9f308d5eaa6b06a726d0cf1c17c713453d904faf405c56`, `00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425`)
2024-03-26 13:57:55.745324500 [c::cs::lmdb_db::lmdb] TRACE Inserted 72 bytes with key '00eaffe31d4c535fb678248078524f9b91f183ca344e6ed52c4ca56f6e50a425' into 'deleted_txo_hash_to_header_index'
```

How Has This Been Tested?
---
System-level testing

What process can a PR reviewer use to test or verify this change?
---
Code review

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Breaking Changes
---

- [x] None
- [ ] Requires data directory on base node to be deleted
- [ ] Requires hard fork
- [ ] Other - Please specify

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<!-- BREAKING CHANGE: Description what the user should do, e.g. delete a
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Co-authored-by: SW van Heerden <swvheerden@gmail.com>

base_layer/core/src/validation/aggregate_body/aggregate_body_chain_validator.rs

@@ -110,27 +110,44 @@ fn validate_input_not_pruned<B: BlockchainBackend>(
     db: &B,
 ) -> Result<Vec<TransactionInput>, ValidationError> {
     let mut inputs: Vec<TransactionInput> = body.inputs().clone();
+    let outputs: Vec<TransactionOutput> = body.outputs().clone();
     for input in &mut inputs {
         if input.is_compact() {
-            let output_mined_info = db
-                .fetch_output(&input.output_hash())?
-                .ok_or(ValidationError::UnknownInput)?;
+            let output = match db.fetch_output(&input.output_hash()) {
+                Ok(val) => match val {
+                    Some(output_mined_info) => output_mined_info.output,
+                    None => {
+                        let input_output_hash = input.output_hash();
+                        if let Some(found) = outputs.iter().find(|o| o.hash() == input_output_hash) {
+                            found.clone()
+                        } else {
+                            warn!(
+                                target: LOG_TARGET,
+                                "Input not found in database or block, commitment: {}, hash: {}",
+                                input.commitment()?.to_hex(), input_output_hash.to_hex()
+                            );
+                            return Err(ValidationError::UnknownInput);
+                        }
+                    },
+                },
+                Err(e) => return Err(ValidationError::from(e)),
+            };
 
-            let rp_hash = match output_mined_info.output.proof {
+            let rp_hash = match output.proof {
                 Some(proof) => proof.hash(),
                 None => FixedHash::zero(),
             };
             input.add_output_data(
-                output_mined_info.output.version,
-                output_mined_info.output.features,
-                output_mined_info.output.commitment,
-                output_mined_info.output.script,
-                output_mined_info.output.sender_offset_public_key,
-                output_mined_info.output.covenant,
-                output_mined_info.output.encrypted_data,
-                output_mined_info.output.metadata_signature,
+                output.version,
+                output.features,
+                output.commitment,
+                output.script,
+                output.sender_offset_public_key,
+                output.covenant,
+                output.encrypted_data,
+                output.metadata_signature,
                 rp_hash,
-                output_mined_info.output.minimum_value_promise,
+                output.minimum_value_promise,
             );
         }
     }
@@ -207,11 +224,16 @@ fn check_inputs_are_utxos<B: BlockchainBackend>(db: &B, body: &AggregateBody) ->
                 }
 
                 let output_hashes = output_hashes.as_ref().unwrap();
-                let output_hash = input.output_hash();
-                if output_hashes.iter().any(|output| output == &output_hash) {
+                let input_output_hash = input.output_hash();
+                if output_hashes.iter().any(|val| val == &input_output_hash) {
                     continue;
                 }
-                not_found_inputs.push(output_hash);
+                warn!(
+                    target: LOG_TARGET,
+                    "Input not found in database, commitment: {}, hash: {}",
+                    input.commitment()?.to_hex(), input_output_hash.to_hex()
+                );
+                not_found_inputs.push(input_output_hash);
             },
             Err(err) => {
                 return Err(err);

base_layer/core/src/validation/helpers.rs

@@ -163,7 +163,8 @@ pub fn is_all_unique_and_sorted<'a, I: IntoIterator<Item = &'a T>, T: PartialOrd
     true
 }
 
-/// This function checks that an input is a valid spendable UTXO
+/// This function checks that an input is a valid spendable UTXO in the database. It cannot confirm
+/// zero confermation transactions.
 pub fn check_input_is_utxo<B: BlockchainBackend>(db: &B, input: &TransactionInput) -> Result<(), ValidationError> {
     let output_hash = input.output_hash();
     if let Some(utxo_hash) = db.fetch_unspent_output_hash_by_commitment(input.commitment()?)? {
@@ -203,7 +204,7 @@ pub fn check_input_is_utxo<B: BlockchainBackend>(db: &B, input: &TransactionInpu
 
     warn!(
         target: LOG_TARGET,
-        "Validation failed due to input: {} which does not exist yet", input
+        "Input ({}, {}) does not exist in the database yet", input.commitment()?.to_hex(), output_hash.to_hex()
     );
     Err(ValidationError::UnknownInput)
 }