From 4b366ef2d479568da7530aa944b73f551bfa346b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20Sch=C3=BCtt?= <felix@wasmer.io>
Date: Fri, 20 Jan 2023 16:29:23 +0100
Subject: [PATCH] Debug provided bytes not deserializing correctly

---
 lib/compiler/src/engine/artifact.rs  |  6 +++---
 lib/types/src/compilation/symbols.rs |  2 +-
 lib/types/src/serialize.rs           | 14 ++++++++++----
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/lib/compiler/src/engine/artifact.rs b/lib/compiler/src/engine/artifact.rs
index 2c917475273..07c4c23c60f 100644
--- a/lib/compiler/src/engine/artifact.rs
+++ b/lib/compiler/src/engine/artifact.rs
@@ -106,9 +106,9 @@ impl Artifact {
                     eprintln!("Could not deserialize as static object: {}", err);
                 }
             }
-            return Err(DeserializeError::Incompatible(
-                "The provided bytes are not wasmer-universal".to_string(),
-            ));
+            return Err(DeserializeError::Incompatible(format!(
+                "Artifact::deserialize: The provided bytes are not wasmer-universal"
+            )));
         }
 
         let bytes = Self::get_byte_slice(bytes, ArtifactBuild::MAGIC_HEADER.len(), bytes.len())?;
diff --git a/lib/types/src/compilation/symbols.rs b/lib/types/src/compilation/symbols.rs
index 81bd8d5ceb7..195f355f787 100644
--- a/lib/types/src/compilation/symbols.rs
+++ b/lib/types/src/compilation/symbols.rs
@@ -123,7 +123,7 @@ impl ModuleMetadata {
     ) -> Result<&ArchivedModuleMetadata, DeserializeError> {
         if metadata_slice.len() < 8 {
             return Err(DeserializeError::Incompatible(
-                "invalid serialized ModuleMetadata".into(),
+                "ModuleMetadata::archive_from_slice: invalid serialized ModuleMetadata".into(),
             ));
         }
         let mut pos: [u8; 8] = Default::default();
diff --git a/lib/types/src/serialize.rs b/lib/types/src/serialize.rs
index 44d051b6418..0b0f76aa954 100644
--- a/lib/types/src/serialize.rs
+++ b/lib/types/src/serialize.rs
@@ -168,7 +168,7 @@ impl SerializableModule {
 /// Metadata header which holds an ABI version and the length of the remaining
 /// metadata.
 #[repr(C)]
-#[derive(Clone, Copy)]
+#[derive(Clone, Debug, Copy)]
 pub struct MetadataHeader {
     magic: [u8; 8],
     version: u32,
@@ -205,6 +205,7 @@ impl MetadataHeader {
 
     /// Parses the header and returns the length of the metadata following it.
     pub fn parse(bytes: &[u8]) -> Result<usize, DeserializeError> {
+        println!("parsing metadata header...");
         if bytes.as_ptr() as usize % 8 != 0 {
             return Err(DeserializeError::CorruptedBinary(
                 "misaligned metadata".to_string(),
@@ -217,18 +218,23 @@ impl MetadataHeader {
             })?
             .try_into()
             .unwrap();
+
+        println!("bytes: {:?}", bytes);
         let header: Self = unsafe { mem::transmute(bytes) };
+        println!("header {:#?}", header);
         if header.magic != Self::MAGIC {
             return Err(DeserializeError::Incompatible(
-                "The provided bytes were not serialized by Wasmer".to_string(),
+                "MetadataHeader::parse: The provided bytes were not serialized by Wasmer"
+                    .to_string(),
             ));
         }
+        println!("header ok!");
         if header.version != Self::CURRENT_VERSION {
             return Err(DeserializeError::Incompatible(
-                "The provided bytes were serialized by an incompatible version of Wasmer"
-                    .to_string(),
+                format!("MetadataHeader::parse: The provided bytes were serialized by an incompatible version of Wasmer: expected version {}, got version {}", Self::CURRENT_VERSION, header.version)
             ));
         }
+        println!("metadata parsing ok!");
         Ok(header.len as usize)
     }
 }