[GraphQL/Data] TransactionBlock Point Queries (MystenLabs#15628)

## Description

Port queries for TransactionBlock by digest into the new data loading
framework.

## Test Plan

```
sui-graphql-rpc$ cargo nextest run
sui-graphql-e2e-tests$ cargo nextest run -j 1 --features pg_nte
```

## Stack
- MystenLabs#15467 
- MystenLabs#15470 
- MystenLabs#15471 
- MystenLabs#15472 
- MystenLabs#15473
- MystenLabs#15474 
- MystenLabs#15475 
- MystenLabs#15484 
- MystenLabs#15485
- MystenLabs#15519
- MystenLabs#15520
- MystenLabs#15521
- MystenLabs#15522
- MystenLabs#15523
- MystenLabs#15524
- MystenLabs#15525
- MystenLabs#15526
- MystenLabs#15527
- MystenLabs#15625 
- MystenLabs#15528
- MystenLabs#15529

crates/sui-graphql-rpc/src/context_data/db_backend.rs

@@ -31,7 +31,6 @@ pub(crate) type BalanceQuery<'a, DB> = BoxedSelectStatement<
 >;
 
 pub(crate) trait GenericQueryBuilder<DB: Backend> {
-    fn get_tx_by_digest(digest: Vec<u8>) -> transactions::BoxedQuery<'static, DB>;
     fn get_obj(address: Vec<u8>, version: Option<i64>) -> objects::BoxedQuery<'static, DB>;
     fn get_obj_by_type(object_type: String) -> objects::BoxedQuery<'static, DB>;
     fn get_display_by_obj_type(object_type: String) -> display::BoxedQuery<'static, DB>;

crates/sui-graphql-rpc/src/context_data/db_data_provider.rs

@@ -139,14 +139,6 @@ impl PgManager {
 
 /// Implement methods to query db and return StoredData
 impl PgManager {
-    async fn get_tx(&self, digest: Vec<u8>) -> Result<Option<StoredTransaction>, Error> {
-        self.run_query_async_with_cost(
-            move || Ok(QueryBuilder::get_tx_by_digest(digest.clone())),
-            |query| move |conn| query.get_result::<StoredTransaction>(conn).optional(),
-        )
-        .await
-    }
-
     async fn get_obj(
         &self,
         address: Vec<u8>,
@@ -482,16 +474,6 @@ impl PgManager {
         }
     }
 
-    pub(crate) async fn fetch_tx(
-        &self,
-        digest: &Digest,
-    ) -> Result<Option<TransactionBlock>, Error> {
-        self.get_tx(digest.to_vec())
-            .await?
-            .map(TransactionBlock::try_from)
-            .transpose()
-    }
-
     /// Retrieve the validator APYs
     pub(crate) async fn fetch_validator_apys(
         &self,

crates/sui-graphql-rpc/src/context_data/pg_backend.rs

@@ -36,11 +36,6 @@ pub(crate) const EXPLAIN_COSTING_LOG_TARGET: &str = "gql-explain-costing";
 pub(crate) struct PgQueryBuilder;
 
 impl GenericQueryBuilder<Pg> for PgQueryBuilder {
-    fn get_tx_by_digest(digest: Vec<u8>) -> transactions::BoxedQuery<'static, Pg> {
-        transactions::dsl::transactions
-            .filter(transactions::dsl::transaction_digest.eq(digest))
-            .into_boxed()
-    }
     fn get_obj(address: Vec<u8>, version: Option<i64>) -> objects::BoxedQuery<'static, Pg> {
         let mut query = objects::dsl::objects.into_boxed();
         query = query.filter(objects::dsl::object_id.eq(address));

crates/sui-graphql-rpc/src/types/object.rs

@@ -196,8 +196,7 @@ impl Object {
         ctx: &Context<'_>,
     ) -> Result<Option<TransactionBlock>> {
         let digest = self.native.previous_transaction;
-        ctx.data_unchecked::<PgManager>()
-            .fetch_tx(&digest.into())
+        TransactionBlock::query(ctx.data_unchecked(), digest.into())
             .await
             .extend()
     }

crates/sui-graphql-rpc/src/types/query.rs

@@ -115,8 +115,7 @@ impl Query {
         ctx: &Context<'_>,
         digest: Digest,
     ) -> Result<Option<TransactionBlock>> {
-        ctx.data_unchecked::<PgManager>()
-            .fetch_tx(&digest)
+        TransactionBlock::query(ctx.data_unchecked(), digest)
             .await
             .extend()
     }

crates/sui-graphql-rpc/src/types/transaction_block.rs

@@ -4,16 +4,20 @@ use async_graphql::{
     connection::{Connection, CursorType, Edge},
     *,
 };
+use diesel::{ExpressionMethods, QueryDsl};
 use fastcrypto::encoding::{Base58, Encoding};
-use sui_indexer::models_v2::transactions::StoredTransaction;
+use sui_indexer::{models_v2::transactions::StoredTransaction, schema_v2::transactions};
 use sui_types::{
     base_types::SuiAddress as NativeSuiAddress,
     transaction::{
         SenderSignedData as NativeSenderSignedData, TransactionDataAPI, TransactionExpiration,
     },
 };
 
-use crate::error::Error;
+use crate::{
+    data::{Db, QueryExecutor},
+    error::Error,
+};
 
 use super::{
     address::Address,
@@ -164,6 +168,22 @@ impl TransactionBlock {
     }
 }
 
+impl TransactionBlock {
+    /// Look up a `TransactionBlock` in the database, by its transaction digest.
+    pub(crate) async fn query(db: &Db, digest: Digest) -> Result<Option<Self>, Error> {
+        use transactions::dsl;
+        db.optional::<_, _, _, _, StoredTransaction>(move || {
+            dsl::transactions
+                .filter(dsl::transaction_digest.eq(digest.to_vec()))
+                .into_boxed()
+        })
+        .await
+        .map_err(|e| Error::Internal(format!("Failed to fetch transaction: {e}")))?
+        .map(TransactionBlock::try_from)
+        .transpose()
+    }
+}
+
 impl TryFrom<StoredTransaction> for TransactionBlock {
     type Error = Error;