Remove (almost all) panickers from trie module (#1776)

* memorydb ub patch and other cleanup

* fix denote invocations

* move trie traits into trie module

* replace "denote" with shim

* triedb returns results and no longer panics

* fix warnings

* get ethcore compiling

* warn on trie errors in ethcore

* remove unsafety from node decoder

* restore broken denote behavior for this branch

* fix overlayrecent fallout

* fix triedb tests

* remove unwrap in state

* alter Trie::get to return Result<Option<_>>

* fix refcell error in require

* fix test warnings

* fix json tests

* whitespace

[ci:skip]

* Avoid unneeded match/indentation

* whitespace

* prettify map_or_else

* remove test warning

ethcore/src/client/client.rs

@@ -183,7 +183,7 @@ impl Client {
 		let tracedb = Arc::new(try!(TraceDB::new(config.tracing, db.clone(), chain.clone())));
 
 		let mut state_db = journaldb::new(db.clone(), config.pruning, DB_COL_STATE);
-		if state_db.is_empty() && spec.ensure_db_good(state_db.as_hashdb_mut()) {
+		if state_db.is_empty() && try!(spec.ensure_db_good(state_db.as_hashdb_mut())) {
 			let batch = DBTransaction::new(&db);
 			try!(state_db.commit(&batch, 0, &spec.genesis_header().hash(), None));
 			try!(db.write(batch).map_err(ClientError::Database));

ethcore/src/client/error.rs

@@ -2,11 +2,15 @@ use trace::Error as TraceError;
 use util::UtilError;
 use std::fmt::{Display, Formatter, Error as FmtError};
 
+use util::trie::TrieError;
+
 /// Client configuration errors.
 #[derive(Debug)]
 pub enum Error {
 	/// TraceDB configuration error.
 	Trace(TraceError),
+	/// TrieDB-related error.
+	Trie(TrieError),
 	/// Database error
 	Database(String),
 	/// Util error
@@ -19,16 +23,29 @@ impl From<TraceError> for Error {
 	}
 }
 
+impl From<TrieError> for Error {
+	fn from(err: TrieError) -> Self {
+		Error::Trie(err)
+	}
+}
+
 impl From<UtilError> for Error {
 	fn from(err: UtilError) -> Self {
 		Error::Util(err)
 	}
 }
 
+impl<E> From<Box<E>> for Error where Error: From<E> {
+	fn from(err: Box<E>) -> Self {
+		Error::from(*err)
+	}
+}
+
 impl Display for Error {
 	fn fmt(&self, f: &mut Formatter) -> Result<(), FmtError> {
 		match *self {
 			Error::Trace(ref err) => write!(f, "{}", err),
+			Error::Trie(ref err) => write!(f, "{}", err),
 			Error::Util(ref err) => write!(f, "{}", err),
 			Error::Database(ref s) => write!(f, "Database error: {}", s),
 		}

ethcore/src/client/test_client.rs

@@ -262,7 +262,7 @@ impl MiningBlockChainClient for TestBlockChainClient {
 		let genesis_header = self.spec.genesis_header();
 		let mut db_result = get_temp_journal_db();
 		let mut db = db_result.take();
-		self.spec.ensure_db_good(db.as_hashdb_mut());
+		self.spec.ensure_db_good(db.as_hashdb_mut()).unwrap();
 
 		let last_hashes = vec![genesis_header.hash()];
 		let mut open_block = OpenBlock::new(