Return error instead of debug assert

With dirty storage we hit the assert. Returning an error permits to continue to
catch if the invariant is broken for normal operation while being able to
continue fuzzing with dirty storage.

libraries/persistent_store/src/format.rs

@@ -335,12 +335,12 @@ impl Format {
     }
 
     /// Builds the storage representation of an init info.
-    pub fn build_init(&self, init: InitInfo) -> WordSlice {
+    pub fn build_init(&self, init: InitInfo) -> StoreResult<WordSlice> {
         let mut word = ERASED_WORD;
-        INIT_CYCLE.set(&mut word, init.cycle);
-        INIT_PREFIX.set(&mut word, init.prefix);
-        WORD_CHECKSUM.set(&mut word, 0);
-        word.as_slice()
+        INIT_CYCLE.set(&mut word, init.cycle)?;
+        INIT_PREFIX.set(&mut word, init.prefix)?;
+        WORD_CHECKSUM.set(&mut word, 0)?;
+        Ok(word.as_slice())
     }
 
     /// Returns the storage index of the compact info of a page.
@@ -368,36 +368,36 @@ impl Format {
     }
 
     /// Builds the storage representation of a compact info.
-    pub fn build_compact(&self, compact: CompactInfo) -> WordSlice {
+    pub fn build_compact(&self, compact: CompactInfo) -> StoreResult<WordSlice> {
         let mut word = ERASED_WORD;
-        COMPACT_TAIL.set(&mut word, compact.tail);
-        WORD_CHECKSUM.set(&mut word, 0);
-        word.as_slice()
+        COMPACT_TAIL.set(&mut word, compact.tail)?;
+        WORD_CHECKSUM.set(&mut word, 0)?;
+        Ok(word.as_slice())
     }
 
     /// Builds the storage representation of an internal entry.
-    pub fn build_internal(&self, internal: InternalEntry) -> WordSlice {
+    pub fn build_internal(&self, internal: InternalEntry) -> StoreResult<WordSlice> {
         let mut word = ERASED_WORD;
         match internal {
             InternalEntry::Erase { page } => {
-                ID_ERASE.set(&mut word);
-                ERASE_PAGE.set(&mut word, page);
+                ID_ERASE.set(&mut word)?;
+                ERASE_PAGE.set(&mut word, page)?;
             }
             InternalEntry::Clear { min_key } => {
-                ID_CLEAR.set(&mut word);
-                CLEAR_MIN_KEY.set(&mut word, min_key);
+                ID_CLEAR.set(&mut word)?;
+                CLEAR_MIN_KEY.set(&mut word, min_key)?;
             }
             InternalEntry::Marker { count } => {
-                ID_MARKER.set(&mut word);
-                MARKER_COUNT.set(&mut word, count);
+                ID_MARKER.set(&mut word)?;
+                MARKER_COUNT.set(&mut word, count)?;
             }
             InternalEntry::Remove { key } => {
-                ID_REMOVE.set(&mut word);
-                REMOVE_KEY.set(&mut word, key);
+                ID_REMOVE.set(&mut word)?;
+                REMOVE_KEY.set(&mut word, key)?;
             }
         }
-        WORD_CHECKSUM.set(&mut word, 0);
-        word.as_slice()
+        WORD_CHECKSUM.set(&mut word, 0)?;
+        Ok(word.as_slice())
     }
 
     /// Parses the first word of an entry from its storage representation.
@@ -459,31 +459,31 @@ impl Format {
     }
 
     /// Builds the storage representation of a user entry.
-    pub fn build_user(&self, key: Nat, value: &[u8]) -> Vec<u8> {
+    pub fn build_user(&self, key: Nat, value: &[u8]) -> StoreResult<Vec<u8>> {
         let length = usize_to_nat(value.len());
         let word_size = self.word_size();
         let footer = self.bytes_to_words(length);
         let mut result = vec![0xff; ((1 + footer) * word_size) as usize];
         result[word_size as usize..][..length as usize].copy_from_slice(value);
         let mut word = ERASED_WORD;
-        ID_HEADER.set(&mut word);
+        ID_HEADER.set(&mut word)?;
         if footer > 0 && is_erased(&result[(footer * word_size) as usize..]) {
             HEADER_FLIPPED.set(&mut word);
             *result.last_mut().unwrap() = 0x7f;
         }
-        HEADER_LENGTH.set(&mut word, length);
-        HEADER_KEY.set(&mut word, key);
+        HEADER_LENGTH.set(&mut word, length)?;
+        HEADER_KEY.set(&mut word, key)?;
         HEADER_CHECKSUM.set(
             &mut word,
             count_zeros(&result[(footer * word_size) as usize..]),
-        );
+        )?;
         result[..word_size as usize].copy_from_slice(&word.as_slice());
-        result
+        Ok(result)
     }
 
     /// Sets the padding bit in the first word of a user entry.
-    pub fn set_padding(&self, word: &mut Word) {
-        ID_PADDING.set(word);
+    pub fn set_padding(&self, word: &mut Word) -> StoreResult<()> {
+        ID_PADDING.set(word)
     }
 
     /// Sets the deleted bit in the first word of a user entry.