type hardening

common/Cargo.toml

@@ -7,6 +7,7 @@ license.workspace = true
 [dependencies]
 prost-types = { workspace = true }
 rust_decimal = { workspace = true }
+rusty-money = { workspace = true }
 
 tonic = "0.14.6"
 prost = "0.14.4"

common/proto/tables_data.proto

@@ -131,7 +131,8 @@ message PostTableDataRequest {
   // - BOOLEAN: bool value
   // - TIMESTAMPTZ: ISO 8601/RFC 3339 string (parsed to TIMESTAMPTZ)
   // - INTEGER: number with no fractional part and within i32 range
-  // - BIGINT: number with no fractional part and within i64 range
+  // - BIGINT: canonical integer string for the full i64 range; a number is
+  //   accepted only within protobuf NumberValue's exact integer range
   // - NUMERIC(p,s): string representation only; empty string becomes NULL
   //   (numbers for NUMERIC are rejected to avoid precision loss)
   //

common/src/lib.rs

@@ -3,6 +3,7 @@
 pub mod search;
 pub mod decimal;
 pub mod grpc_error;
+pub mod money;
 pub mod relationship;
 pub mod system_column;
 

common/src/money.rs

@@ -0,0 +1,53 @@
+// common/src/money.rs
+//!
+//! The one canonical currency spelling shared by the client and the server.
+//!
+//! A currency code is stored, sent and compared as its canonical uppercase
+//! ISO-4217 alphabetic code. Both ends resolve it with
+//! [`require_iso_currency_code`], so the client rejects exactly what the server
+//! would reject, and each side renders the shared error as its own error type.
+
+pub use rusty_money::iso;
+
+/// Resolves a canonical uppercase ISO-4217 alphabetic code to its currency.
+///
+/// Rejects anything not already canonical: lowercase (`eur`), surrounding
+/// whitespace, and any length but three. Normalising here instead would let a
+/// value be written in one spelling and compared in another.
+pub fn require_iso_currency_code(currency_code: &str) -> Result<&'static iso::Currency, String> {
+    if currency_code.len() != 3
+        || !currency_code
+            .chars()
+            .all(|character| character.is_ascii_uppercase())
+    {
+        return Err("Currency must be a canonical uppercase ISO-4217 code".to_string());
+    }
+
+    iso::find(currency_code).ok_or_else(|| format!("Unknown ISO-4217 currency: {currency_code}"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn canonical_codes_resolve_to_their_currency() {
+        assert_eq!(require_iso_currency_code("EUR").unwrap(), iso::EUR);
+        assert_eq!(
+            require_iso_currency_code("USD").unwrap().iso_alpha_code,
+            "USD"
+        );
+    }
+
+    #[test]
+    fn non_canonical_or_unknown_codes_are_rejected() {
+        for currency_code in [
+            "", "E", "EU", "EURO", "eur", "Eur", " EUR", "EUR ", "E R", "E\u{20AC}R", "AAA", "123",
+        ] {
+            assert!(
+                require_iso_currency_code(currency_code).is_err(),
+                "unexpectedly accepted {currency_code:?}"
+            );
+        }
+    }
+}

common/src/proto/komp_ac.tables_data.rs

@@ -27,7 +27,8 @@ pub struct PostTableDataRequest {
     /// * BOOLEAN: bool value
     /// * TIMESTAMPTZ: ISO 8601/RFC 3339 string (parsed to TIMESTAMPTZ)
     /// * INTEGER: number with no fractional part and within i32 range
-    /// * BIGINT: number with no fractional part and within i64 range
+    /// * BIGINT: canonical integer string for the full i64 range; a number is
+    ///   accepted only within protobuf NumberValue's exact integer range
     /// * NUMERIC(p,s): string representation only; empty string becomes NULL
     ///   (numbers for NUMERIC are rejected to avoid precision loss)
     ///