graph: Track diesel's bigdecimal version and drop vendored PG codec

Our `BigDecimal` wrapped `bigdecimal = 0.1.2` (renamed `old_bigdecimal`) to
avoid diesel's numeric ToSql/FromSql impls targeting a distinct type, and to
avoid a PoI divergence attributed to the upgrade. That forced `num-bigint`
to `=0.2.6` and required ~150 lines of vendored PgNumeric codec.

Move `bigdecimal` and `num-bigint` into `[workspace.dependencies]` (0.3 and
0.4, unpinned), so our newtype wraps the same type diesel ships impls for.
The vendored `mod pg` collapses to two ToSql/FromSql delegations. The
`big_decimal_stable` PoI hashes remain unchanged.

`num-bigint` 0.4 returns `u64` from `BigInt::bits()` and requires a typed
operand for `Shl`/`Shr`; adjust `BigInt` wrapper accordingly.

Author: lutter

Cargo.lock

@@ -42,6 +42,7 @@ async-graphql = { version = "7.2.1", features = ["chrono"] }
 async-graphql-axum = "7.2.1"
 async-trait = "0.1.74"
 axum = "0.8.8"
+bigdecimal = { version = "0.3", features = ["serde"] }
 chrono = "0.4.44"
 bs58 = "0.5.1"
 clap = { version = "4.5.4", features = ["derive", "env", "wrap_help"] }
@@ -75,6 +76,7 @@ indicatif = "0.18"
 Inflector = "0.11.3"
 itertools = "0.14.0"
 lazy_static = "1.5.0"
+num-bigint = { version = "0.4", features = ["serde"] }
 prost = "0.14"
 prost-types = "0.14"
 redis = { version = "1.2.0", features = [

Cargo.toml

@@ -10,12 +10,7 @@ anyhow = "1.0"
 async-trait = { workspace = true }
 async-stream = "0.3"
 atomic_refcell = "0.1.13"
-# We require this precise version of bigdecimal. Updating to later versions
-# has caused PoI differences; if you update this version, you will need to
-# make sure that it does not cause PoI changes
-old_bigdecimal = { version = "=0.1.2", features = [
-    "serde",
-], package = "bigdecimal" }
+bigdecimal.workspace = true
 bytes = "1.0.1"
 bs58 = { workspace = true }
 cid = "0.11.1"
@@ -37,7 +32,7 @@ futures01 = { package = "futures", version = "0.1.31" }
 lru_time_cache = "0.11"
 graphql-tools = { workspace = true }
 lazy_static = { workspace = true }
-num-bigint = { version = "=0.2.6", features = ["serde"] }
+num-bigint.workspace = true
 num-integer = { version = "=0.1.46" }
 num-traits = "=0.2.19"
 rand.workspace = true

graph/Cargo.toml

@@ -359,8 +359,8 @@ impl From<FromHexError> for QueryExecutionError {
     }
 }
 
-impl From<old_bigdecimal::ParseBigDecimalError> for QueryExecutionError {
-    fn from(e: old_bigdecimal::ParseBigDecimalError) -> Self {
+impl From<bigdecimal::ParseBigDecimalError> for QueryExecutionError {
+    fn from(e: bigdecimal::ParseBigDecimalError) -> Self {
         QueryExecutionError::ValueParseError("BigDecimal".to_string(), format!("{}", e))
     }
 }