fix: read inet and cidr results with their prefix, including arrays (#11476)

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

backend/Cargo.lock

@@ -16773,6 +16773,7 @@ dependencies = [
  "pem",
  "pep440_rs",
  "postgres-native-tls 0.5.3",
+ "postgres-protocol",
  "process-wrap",
  "prometheus",
  "prost",

backend/windmill-worker/Cargo.toml

@@ -101,6 +101,7 @@ mappable-rc.workspace = true
 git-version.workspace = true
 once_cell.workspace = true
 tokio-postgres.workspace = true
+postgres-protocol.workspace = true
 bit-vec.workspace = true
 url.workspace = true
 async-stream.workspace = true

backend/windmill-worker/src/pg_executor.rs

@@ -1,5 +1,4 @@
 use std::collections::{HashMap, HashSet};
-use std::net::IpAddr;
 use std::sync::atomic::{AtomicU64, AtomicUsize, Ordering};
 use std::sync::Arc;
 use std::time::Duration;
@@ -1889,8 +1888,8 @@ pub fn pg_cell_to_json_value_with_state(
         Type::UUID => get_basic(row, column, column_i, |a: uuid::Uuid| {
             Ok(JSONValue::String(a.to_string()))
         })?,
-        Type::INET => get_basic(row, column, column_i, |a: IpAddr| {
-            Ok(JSONValue::String(a.to_string()))
+        Type::INET | Type::CIDR => get_basic(row, column, column_i, |a: InetStr| {
+            Ok(JSONValue::String(a.0))
         })?,
         Type::INTERVAL => get_basic(row, column, column_i, |a: IntervalStr| {
             Ok(JSONValue::String(a.0))
@@ -1997,6 +1996,9 @@ pub fn pg_cell_to_json_value_with_state(
         Type::BYTEA_ARRAY => get_array(row, column, column_i, |a: Vec<u8>| {
             Ok(JSONValue::String(format!("\\x{}", hex::encode(a))))
         })?,
+        Type::INET_ARRAY | Type::CIDR_ARRAY => get_array(row, column, column_i, |a: InetStr| {
+            Ok(JSONValue::String(a.0))
+        })?,
         Type::VOID => JSONValue::Null,
         // Default fallback for unhandled column types: read as text. We use
         // `AnyTextValue` instead of plain `String` so that `Kind::Enum`,
@@ -2156,6 +2158,29 @@ fn get_array<'a, T: FromSql<'a>>(
     })
 }
 
+/// `inet` / `cidr` in Postgres's own text form. `IpAddr`'s `FromSql` drops the
+/// prefix length, so a network such as `10.0.0.0/8` would read back as a host.
+struct InetStr(String);
+impl FromSql<'_> for InetStr {
+    fn from_sql(
+        ty: &Type,
+        raw: &[u8],
+    ) -> Result<InetStr, Box<dyn std::error::Error + Sync + Send>> {
+        let inet = postgres_protocol::types::inet_from_sql(raw)?;
+        let host_prefix = if inet.addr().is_ipv4() { 32 } else { 128 };
+        Ok(InetStr(
+            if *ty == Type::CIDR || inet.netmask() != host_prefix {
+                format!("{}/{}", inet.addr(), inet.netmask())
+            } else {
+                inet.addr().to_string()
+            },
+        ))
+    }
+    fn accepts(ty: &Type) -> bool {
+        matches!(*ty, Type::INET | Type::CIDR)
+    }
+}
+
 // you can remove this section if not using TS_VECTOR (or other types requiring an intermediary `FromSQL` struct)
 struct StringCollector(String);
 impl FromSql<'_> for StringCollector {
@@ -2271,6 +2296,19 @@ mod tests {
         );
     }
 
+    #[test]
+    fn inet_keeps_the_prefix_postgres_prints() {
+        let inet = |netmask: u8, addr: [u8; 4]| {
+            let mut raw = vec![2, netmask, 0, 4];
+            raw.extend(addr);
+            raw
+        };
+        let read = |ty: &Type, raw: &[u8]| InetStr::from_sql(ty, raw).unwrap().0;
+        assert_eq!(read(&Type::INET, &inet(32, [10, 1, 2, 3])), "10.1.2.3");
+        assert_eq!(read(&Type::INET, &inet(8, [10, 0, 0, 0])), "10.0.0.0/8");
+        assert_eq!(read(&Type::CIDR, &inet(32, [10, 1, 2, 3])), "10.1.2.3/32");
+    }
+
     #[test]
     fn test_parse_naive_date() {
         // chrono's NaiveDate::to_string() format