feat(deserializer): protect against corrupted binary files

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/kernel/expr.cpp

@@ -459,7 +459,7 @@ public:
                     name n = read_name(d);
                     return mk_metavar(n, read_local_context(d));
                 }}
-                lean_unreachable(); // LCOV_EXCL_LINE
+                throw_corrupted_file();
             });
     }
 };

src/kernel/level.cpp

@@ -308,7 +308,7 @@ public:
                     }
                     return max_core(lvls.size(), lvls.data());
                 }}
-                lean_unreachable();
+                throw_corrupted_file();
             });
     }
 };

src/util/name.cpp

@@ -404,7 +404,7 @@ public:
                     name prefix = read();
                     return name(prefix, d.read_unsigned());
                 }}
-                lean_unreachable(); // LCOV_EXCL_LINE
+                throw_corrupted_file();
             });
     }
 };

src/util/object_serializer.h

@@ -7,7 +7,6 @@ Author: Leonardo de Moura
 #pragma once
 #include <unordered_map>
 #include <vector>
-#include "util/exception.h"
 #include "util/serializer.h"
 
 #ifndef LEAN_OBJECT_SERIALIZER_BUCKET_SIZE
@@ -62,7 +61,7 @@ public:
         } else {
             unsigned i = d.read_unsigned();
             if (i >= m_table.size())
-                throw exception("corrupted binary file");
+                throw_corrupted_file();
             return m_table[i];
         }
     }

src/util/serializer.cpp

@@ -9,6 +9,7 @@ Author: Leonardo de Moura
 #include <stdio.h>
 #include <ios>
 #include "util/serializer.h"
+#include "util/exception.h"
 
 namespace lean {
 void serializer_core::write_unsigned(unsigned i) {
@@ -69,4 +70,8 @@ double deserializer_core::read_double() {
     in >> r;
     return r;
 }
+
+void throw_corrupted_file() {
+    throw exception("corrupted binary file");
+}
 }

src/util/serializer.h

@@ -63,4 +63,6 @@ inline deserializer & operator>>(deserializer & d, int & i) { i = d.read_int();
 inline deserializer & operator>>(deserializer & d, char & c) { c = d.read_char(); return d; }
 inline deserializer & operator>>(deserializer & d, bool & b) { b = d.read_bool(); return d; }
 inline deserializer & operator>>(deserializer & d, double & b) { b = d.read_double(); return d; }
+
+[[ noreturn ]] void throw_corrupted_file();
 }

src/util/sexpr/sexpr.cpp

@@ -336,7 +336,7 @@ public:
                     sexpr t = read();
                     return sexpr(h, t);
                 }}
-                lean_unreachable();
+                throw_corrupted_file();
             });
     }
 };