amd-efs#99 Improve dumping of image contents with unknown parts.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "amd-efs"
-version = "0.3.1"
+version = "0.3.2"
 authors = ["Oxide Computer Company"]
 edition = "2018"
 

src/ondisk.rs

@@ -737,7 +737,7 @@ macro_rules! make_bitfield_serde {(
 
     #[cfg(feature = "serde")]
     paste::paste! {
-        #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+        #[cfg_attr(feature = "serde", derive(serde::Deserialize))]
         #[cfg_attr(feature = "serde", serde(deny_unknown_fields))]
         #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
         #[cfg_attr(feature = "serde", serde(rename = "" $StructName))]
@@ -748,6 +748,25 @@ macro_rules! make_bitfield_serde {(
             )*
         }
     }
+
+    #[cfg(feature = "serde")]
+    paste::paste!{
+        /// Use this for serialization in order to make serde skip those fields
+        /// where the meaning of a raw value is unknown to us.
+        ///
+        /// Caller can then override Serializer::skip_field and thus find out
+        /// which fields were skipped, inferring where errors were.
+        #[doc(hidden)]
+        #[allow(non_camel_case_types)]
+        #[cfg_attr(feature = "serde", derive(serde::Serialize))]
+        #[cfg_attr(feature = "serde", serde(rename = "" $StructName))]
+        pub(crate) struct [<SerdePermissiveSerializing $StructName>] {
+            $(
+                $(#[serde(skip_serializing_if="Option::is_none")] pub $field_name: Option<$field_ty>,)?
+                $(#[serde(skip_serializing_if="Option::is_none")] $(#[$serde_field_orig_meta])* pub $field_name: Option<$serde_ty>,)?
+            )*
+        }
+    }
 }}
 
 make_bitfield_serde! {

src/serializers.rs

@@ -8,7 +8,7 @@
 use crate::ondisk::*;
 
 // Note: This is written such that it will fail if the underlying struct has fields added/removed/renamed--if those have a public setter.
-macro_rules! make_serde{($StructName:ident, $SerdeStructName:ident, [$($field_name:ident),* $(,)?]
+macro_rules! impl_struct_serde_conversion{($StructName:ident, $SerdeStructName:ident, $SerializingStructName:ident, [$($field_name:ident),* $(,)?]
 ) => (
     paste::paste!{
         #[cfg(feature = "serde")]
@@ -26,9 +26,9 @@ macro_rules! make_serde{($StructName:ident, $SerdeStructName:ident, [$($field_na
         impl serde::Serialize for $StructName {
             fn serialize<S>(&self, serializer: S) -> core::result::Result<S::Ok, S::Error>
             where S: serde::Serializer, {
-                $SerdeStructName {
+                $SerializingStructName {
                     $(
-                        $field_name: self.[<serde_ $field_name>]().map_err(|_| serde::ser::Error::custom("value unknown"))?.into(),
+                        $field_name: self.[<serde_ $field_name>]().ok(),
                     )*
                 }.serialize(serializer)
             }
@@ -48,14 +48,16 @@ macro_rules! make_serde{($StructName:ident, $SerdeStructName:ident, [$($field_na
     }
 )}
 
-make_serde!(
+impl_struct_serde_conversion!(
     DirectoryAdditionalInfo,
     SerdeDirectoryAdditionalInfo,
+    SerdePermissiveSerializingDirectoryAdditionalInfo,
     [max_size, spi_block_size, base_address, address_mode, _reserved_0,]
 );
-make_serde!(
+impl_struct_serde_conversion!(
     PspSoftFuseChain,
     SerdePspSoftFuseChain,
+    SerdePermissiveSerializingPspSoftFuseChain,
     [
         secure_debug_unlock,
         _reserved_0,

src/struct_accessors.rs

@@ -311,22 +311,28 @@ macro_rules! make_accessors {(
             )?
         )*
     }
-    // for serde
     #[cfg(feature = "serde")]
     paste::paste!{
+        /// Use this for serialization in order to make serde skip those fields
+        /// where the meaning of a raw value is unknown to us.
+        ///
+        /// Caller can then override Serializer::skip_field and thus find out
+        /// which fields were skipped, inferring where errors were.
         #[doc(hidden)]
         #[allow(non_camel_case_types)]
-        #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
-        #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
-        // Doing remoting automatically would make it impossible for the user to use another one.
-        // Since the config format presumably needs to be
-        // backward-compatible, that wouldn't be such a great idea.
+        #[cfg_attr(feature = "serde", derive(serde::Serialize))]
         #[cfg_attr(feature = "serde", serde(rename = "" $StructName))]
-        #[cfg_attr(feature = "serde", serde(deny_unknown_fields))]
-        pub(crate) struct [<Serde $StructName>] {
+        // Rust's serde automatically has Options transparent--but not Results.
+        // See also <https://github.com/serde-rs/serde/issues/1042> for
+        // limitations (that don't hit us since our zerocopy structs
+        // can't have Option<Option<T>> anyway).
+        pub(crate) struct [<SerdePermissiveSerializing $StructName>] {
             $(
-                $(pub $field_name: $field_ty,)?
-                $($(#[$serde_field_orig_meta])* pub $field_name: $serde_ty,)?
+                $(#[serde(skip_serializing_if="Option::is_none")]
+                pub $field_name: Option<$field_ty>,)?
+                $(#[serde(skip_serializing_if="Option::is_none")]
+                $(#[$serde_field_orig_meta])*
+                pub $field_name: Option<$serde_ty>,)?
             )*
         }
     }