feat(types): add SQLSTATE codes for undefined-function/div0 (#216)

Add UNDEFINED_FUNCTION (SQLSTATE 42883) and DIVISION_BY_ZERO
(SQLSTATE 22012) as first-class ErrorCode/ErrorDetails variants, with
msgpack wire tags, encode/decode support, and NodeDbError
constructors. Purely additive plumbing: both codes are unused until
the callers that raise them land in a follow-up commit.

Today a function call naming no registered scalar/aggregate/window
function, or an expression that divides or takes a modulus by zero,
silently folds to NULL instead of failing the statement — this gives
those two cases a distinct, matchable error identity instead of
forcing clients to parse a generic message.

Author: emanzx

nodedb-types/src/error/code.rs

@@ -43,6 +43,10 @@ impl ErrorCode {
     pub const PLAN_ERROR: Self = Self(1200);
     pub const FAN_OUT_EXCEEDED: Self = Self(1201);
     pub const SQL_NOT_ENABLED: Self = Self(1202);
+    /// A function call names no registered scalar/aggregate/window function.
+    pub const UNDEFINED_FUNCTION: Self = Self(1203);
+    /// Expression evaluation divided or took a modulus by zero.
+    pub const DIVISION_BY_ZERO: Self = Self(1204);
 
     // Engine ops (1300–1399)
     pub const ARRAY: Self = Self(1300);

nodedb-types/src/error/ctors/read_query_auth.rs

@@ -120,6 +120,33 @@ impl NodeDbError {
         }
     }
 
+    /// A function call in a query names no registered scalar, aggregate, or
+    /// window function. Distinct from `plan_error` so clients can match on
+    /// the specific code (SQLSTATE `42883`, `undefined_function`) rather
+    /// than parsing the message.
+    pub fn undefined_function(name: impl Into<String>) -> Self {
+        let name = name.into();
+        Self {
+            code: ErrorCode::UNDEFINED_FUNCTION,
+            message: format!("function {name}(...) does not exist"),
+            details: ErrorDetails::UndefinedFunction { name },
+            cause: None,
+        }
+    }
+
+    /// Expression evaluation divided or took a modulus by zero. Distinct
+    /// from `plan_error` so clients can match on the specific code
+    /// (SQLSTATE `22012`, `division_by_zero`) rather than parsing the
+    /// message (nodedb issue #216).
+    pub fn division_by_zero() -> Self {
+        Self {
+            code: ErrorCode::DIVISION_BY_ZERO,
+            message: "division by zero".to_string(),
+            details: ErrorDetails::DivisionByZero,
+            cause: None,
+        }
+    }
+
     pub fn authorization_denied(resource: impl Into<String>) -> Self {
         let resource = resource.into();
         Self {

nodedb-types/src/error/details.rs

@@ -80,6 +80,12 @@ pub enum ErrorDetails {
     FanOutExceeded { shards_touched: u16, limit: u16 },
     #[serde(rename = "sql_not_enabled")]
     SqlNotEnabled,
+    /// A function call names no registered scalar/aggregate/window function.
+    #[serde(rename = "undefined_function")]
+    UndefinedFunction { name: String },
+    /// Expression evaluation divided or took a modulus by zero.
+    #[serde(rename = "division_by_zero")]
+    DivisionByZero,
 
     // Auth
     #[serde(rename = "authorization_denied")]

nodedb-types/src/error/msgpack/constants.rs

@@ -69,6 +69,11 @@
 // |  61 | MoveTenantSnapshotFailed  |
 // |  62 | MoveTenantCutoverFailed   |
 // |  63 | MoveTenantAlreadyAtTarget |
+// |  64 | MirrorReadOnly            |
+// |  65 | StaleReadNotLeader        |
+// |  66 | MirrorNotPromoted         |
+// |  67 | UndefinedFunction         |
+// |  68 | DivisionByZero            |
 
 pub(super) const TAG_CONSTRAINT_VIOLATION: u16 = 1;
 pub(super) const TAG_WRITE_CONFLICT: u16 = 2;
@@ -136,3 +141,5 @@ pub(super) const TAG_MOVE_TENANT_ALREADY_AT_TARGET: u16 = 63;
 pub(super) const TAG_MIRROR_READ_ONLY: u16 = 64;
 pub(super) const TAG_STALE_READ_NOT_LEADER: u16 = 65;
 pub(super) const TAG_MIRROR_NOT_PROMOTED: u16 = 66;
+pub(super) const TAG_UNDEFINED_FUNCTION: u16 = 67;
+pub(super) const TAG_DIVISION_BY_ZERO: u16 = 68;

nodedb-types/src/error/msgpack/decode/from_messagepack.rs

@@ -123,6 +123,14 @@ impl<'a> FromMessagePack<'a> for ErrorDetails {
                 skip_fields(reader, field_count)?;
                 Ok(ErrorDetails::SqlNotEnabled)
             }
+            TAG_UNDEFINED_FUNCTION => {
+                let (name,) = read1_str(reader, field_count)?;
+                Ok(ErrorDetails::UndefinedFunction { name })
+            }
+            TAG_DIVISION_BY_ZERO => {
+                skip_fields(reader, field_count)?;
+                Ok(ErrorDetails::DivisionByZero)
+            }
             TAG_AUTHORIZATION_DENIED => {
                 let (resource,) = read1_str(reader, field_count)?;
                 Ok(ErrorDetails::AuthorizationDenied { resource })
@@ -346,6 +354,7 @@ mod tests {
         for v in [
             ErrorDetails::DeadlineExceeded,
             ErrorDetails::SqlNotEnabled,
+            ErrorDetails::DivisionByZero,
             ErrorDetails::AuthExpired,
             ErrorDetails::SyncConnectionFailed,
             ErrorDetails::Config,

nodedb-types/src/error/msgpack/encode.rs

@@ -153,6 +153,10 @@ impl ToMessagePack for ErrorDetails {
                 limit,
             } => write2(writer, TAG_FAN_OUT_EXCEEDED, shards_touched, limit),
             ErrorDetails::SqlNotEnabled => write_unit(writer, TAG_SQL_NOT_ENABLED),
+            ErrorDetails::UndefinedFunction { name } => {
+                write1(writer, TAG_UNDEFINED_FUNCTION, name)
+            }
+            ErrorDetails::DivisionByZero => write_unit(writer, TAG_DIVISION_BY_ZERO),
             ErrorDetails::AuthorizationDenied { resource } => {
                 write1(writer, TAG_AUTHORIZATION_DENIED, resource)
             }

nodedb-types/src/error/sqlstate.rs

@@ -40,6 +40,10 @@ pub const CANNOT_DROP_DEFAULT_DATABASE: &str = "0A000";
 /// `22003` — `numeric_value_out_of_range`
 pub const NUMERIC_VALUE_OUT_OF_RANGE: &str = "22003";
 
+/// `22012` — `division_by_zero` (`/` or `%` with a zero divisor; nodedb
+/// issue #216 — raised at runtime instead of evaluating to `NULL`)
+pub const DIVISION_BY_ZERO: &str = "22012";
+
 // ── Class 23 — Integrity Constraint Violation ────────────────────────────────
 
 /// `23000` — `integrity_constraint_violation` (generic)
@@ -105,6 +109,10 @@ pub const CANNOT_COERCE: &str = "42846";
 /// `42P01` — `undefined_table` (collection not found)
 pub const UNDEFINED_TABLE: &str = "42P01";
 
+/// `42883` — `undefined_function` (no scalar/aggregate/window function
+/// registered under the called name)
+pub const UNDEFINED_FUNCTION: &str = "42883";
+
 // ── Class 53 — Insufficient Resources ────────────────────────────────────────
 
 /// `53200` — `out_of_memory`
@@ -237,6 +245,7 @@ mod tests {
             NO_DATA,
             FEATURE_NOT_SUPPORTED,
             NUMERIC_VALUE_OUT_OF_RANGE,
+            DIVISION_BY_ZERO,
             INTEGRITY_CONSTRAINT_VIOLATION,
             NOT_NULL_VIOLATION,
             FOREIGN_KEY_VIOLATION,
@@ -256,6 +265,7 @@ mod tests {
             SYNTAX_ERROR,
             CANNOT_COERCE,
             UNDEFINED_TABLE,
+            UNDEFINED_FUNCTION,
             OUT_OF_MEMORY,
             TOO_MANY_CONNECTIONS,
             CONFIGURATION_LIMIT_EXCEEDED,

nodedb-types/src/error/types.rs

@@ -98,6 +98,8 @@ impl NodeDbError {
                 | ErrorDetails::AuthExpired
                 | ErrorDetails::Config
                 | ErrorDetails::SqlNotEnabled
+                | ErrorDetails::UndefinedFunction { .. }
+                | ErrorDetails::DivisionByZero
         )
     }
 }