fix(core): tweak serialization impls to fix offline mode

sqlx-core/Cargo.toml

@@ -72,7 +72,7 @@ parking_lot = "0.10.2"
 threadpool = "*"
 phf = { version = "0.8.0", features = [ "macros" ] }
 rand = { version = "0.7.3", default-features = false, optional = true, features = [ "std" ] }
-serde = { version = "1.0.106", features = [ "derive" ], optional = true }
+serde = { version = "1.0.106", features = [ "derive", "rc" ], optional = true }
 serde_json = { version = "1.0.51", features = [ "raw_value" ], optional = true }
 sha-1 = { version = "0.8.2", default-features = false, optional = true }
 sha2 = { version = "0.8.1", default-features = false, optional = true }

sqlx-core/src/ext/ustr.rs

@@ -8,7 +8,6 @@ use std::sync::Arc;
 // a micro-string is either a reference-counted string or a static string
 // this guarantees these are cheap to clone everywhere
 #[derive(Debug, Clone, Eq)]
-#[cfg_attr(feature = "offline", derive(serde::Serialize, serde::Deserialize))]
 pub(crate) enum UStr {
     Static(&'static str),
     Shared(Arc<str>),
@@ -75,3 +74,28 @@ impl Display for UStr {
         f.pad(self)
     }
 }
+
+// manual impls because otherwise things get a little screwy with lifetimes
+
+#[cfg(feature = "offline")]
+impl<'de> serde::Deserialize<'de> for UStr {
+    fn deserialize<D>(deserializer: D) -> Result<Self, <D as serde::Deserializer<'de>>::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        Ok(String::deserialize(deserializer)?.into())
+    }
+}
+
+#[cfg(feature = "offline")]
+impl serde::Serialize for UStr {
+    fn serialize<S>(
+        &self,
+        serializer: S,
+    ) -> Result<<S as serde::Serializer>::Ok, <S as serde::Serializer>::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(&self)
+    }
+}

sqlx-core/src/postgres/type_info.rs

@@ -109,7 +109,7 @@ pub(crate) enum PgType {
     Custom(Arc<PgCustomType>),
 
     // From [`PgTypeInfo::with_name`]
-    DeclareWithName(&'static str),
+    DeclareWithName(UStr),
 
     // NOTE: Do we want to bring back type declaration by ID? It's notoriously fragile but
     //       someone may have a user for it
@@ -194,7 +194,7 @@ impl PgTypeInfo {
     /// The OID for the type will be fetched from Postgres on use of
     /// a value of this type. The fetched OID will be cached per-connection.
     pub const fn with_name(name: &'static str) -> Self {
-        Self(PgType::DeclareWithName(name))
+        Self(PgType::DeclareWithName(UStr::Static(name)))
     }
 
     pub(crate) const fn with_oid(oid: u32) -> Self {

sqlx-core/src/postgres/types/array.rs

@@ -3,7 +3,6 @@ use bytes::Buf;
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
-use crate::ext::ustr::UStr;
 use crate::postgres::type_info::PgType;
 use crate::postgres::{PgArgumentBuffer, PgTypeInfo, PgValueFormat, PgValueRef, Postgres};
 use crate::types::Type;
@@ -49,7 +48,7 @@ where
 
         // element type
         match T::type_info().0 {
-            PgType::DeclareWithName(name) => buf.push_type_hole(&UStr::Static(name)),
+            PgType::DeclareWithName(name) => buf.push_type_hole(&name),
 
             ty => {
                 buf.extend(&ty.oid().to_be_bytes());

sqlx-core/src/postgres/types/record.rs

@@ -3,7 +3,6 @@ use bytes::Buf;
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::{mismatched_types, BoxDynError};
-use crate::ext::ustr::UStr;
 use crate::postgres::type_info::PgType;
 use crate::postgres::{
     PgArgumentBuffer, PgTypeInfo, PgTypeKind, PgValueFormat, PgValueRef, Postgres,
@@ -44,7 +43,7 @@ impl<'a> PgRecordEncoder<'a> {
         if let PgType::DeclareWithName(name) = ty.0 {
             // push a hole for this type ID
             // to be filled in on query execution
-            self.buf.push_type_hole(&UStr::Static(name));
+            self.buf.push_type_hole(&name);
         } else {
             // write type id
             self.buf.extend(&ty.0.oid().to_be_bytes());