[bettereng] Fold a bunch of panics into the Error case of their Result

Note one case in the github secure storage is a panic occurring in
case an invalid UTF8 encoding is parsed anywhere in the storage, which
does not bode well.

language/move-lang/src/shared/mod.rs

@@ -42,7 +42,8 @@ impl Address {
             hex_string.insert(0, '0');
         }
 
-        let mut result = hex::decode(hex_string.as_str()).unwrap();
+        let mut result = hex::decode(hex_string.as_str())
+            .map_err(|_| "hex string does not decode properly".to_owned())?;
         let len = result.len();
         if len < ADDRESS_LENGTH {
             result.reverse();

language/move-prover/stackless-bytecode-generator/src/borrow_analysis.rs

@@ -488,7 +488,10 @@ impl<'a> BorrowAnalysis<'a> {
         let livevar_annotation_at = self
             .livevar_annotation
             .get_live_var_info_at(code_offset)
-            .unwrap();
+            .ok_or_else(|| PackError {
+                code_offset,
+                indices,
+            })?;
         for idx in livevar_annotation_at
             .before
             .difference(&livevar_annotation_at.after)

language/move-prover/stackless-bytecode-generator/src/packref_analysis.rs

@@ -94,7 +94,7 @@ impl<'a> CopyAnalysis<'a> {
         let after_refs = &self
             .borrow_annotation
             .get_borrow_info_at(code_offset)
-            .unwrap()
+            .ok_or_else(|| ())?
             .after
             .all_refs();
         post.copies = post.copies.intersection(after_refs).cloned().collect();

secure/storage/src/github.rs

@@ -34,7 +34,9 @@ impl KVStorage for GitHubStorage {
     fn get<T: DeserializeOwned>(&self, key: &str) -> Result<GetResponse<T>, Error> {
         let data = self.client.get_file(key)?;
         let data = base64::decode(&data)?;
-        let data = std::str::from_utf8(&data).unwrap();
+        let data = std::str::from_utf8(&data).map_err(|_| {
+            Error::InternalError("Unparseable data returned from Github KV Storage".into())
+        })?;
         serde_json::from_str(&data).map_err(|e| e.into())
     }
 

testsuite/cli/libra-wallet/src/mnemonic.rs

@@ -77,7 +77,9 @@ impl Mnemonic {
         bit_writer.write_buffer();
 
         // This will never fail as we've already checked the word-list is not empty.
-        let (checksum, entropy) = bit_writer.bytes.split_last().unwrap();
+        let (checksum, entropy) = bit_writer.bytes.split_last().ok_or_else(|| {
+            WalletError::LibraWalletGeneric("Bit writer producing inconsistent byte strings".into())
+        })?;
         let computed_checksum = Sha256::digest(entropy)[0] >> (8 - len / 3);
         // Checksum validation.
         if *checksum != computed_checksum {