Ensure all SQLAlchemy exception can be properly pickled

Implemented proper ``__reduce__()`` methods for all SQLAlchemy exception
objects to ensure they all support clean round trips when pickling, as
exception objects are often serialized for the purposes of various
debugging tools.

Fixes  #7077
Closes: #7078
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/7078
Pull-request-sha: 8ba69f26532f0f60f679289702c9477e25149bf8

Change-Id: Id62f8d351cd9180c441ffa9201efcf5f1876bf83

1 files changed, 20 insertions, 2 deletions

diff --git a/lib/sqlalchemy/exc.py b/lib/sqlalchemy/exc.py
index a24cf7ba4..afda1b779 100644
--- a/lib/sqlalchemy/exc.py
+++ b/lib/sqlalchemy/exc.py
@@ -118,6 +118,10 @@ class ObjectNotExecutableError(ArgumentError):
         super(ObjectNotExecutableError, self).__init__(
             "Not an executable object: %r" % target
         )
+        self.target = target
+
+    def __reduce__(self):
+        return self.__class__, (self.target,)
 
 
 class NoSuchModuleError(ArgumentError):
@@ -164,7 +168,11 @@ class CircularDependencyError(SQLAlchemyError):
         self.edges = edges
 
     def __reduce__(self):
-        return self.__class__, (None, self.cycles, self.edges, self.args[0])
+        return (
+            self.__class__,
+            (None, self.cycles, self.edges, self.args[0]),
+            {"code": self.code} if self.code is not None else {},
+        )
 
 
 class CompileError(SQLAlchemyError):
@@ -188,6 +196,12 @@ class UnsupportedCompilationError(CompileError):
             "Compiler %r can't render element of type %s%s"
             % (compiler, element_type, ": %s" % message if message else "")
         )
+        self.compiler = compiler
+        self.element_type = element_type
+        self.message = message
+
+    def __reduce__(self):
+        return self.__class__, (self.compiler, self.element_type, self.message)
 
 
 class IdentifierError(SQLAlchemyError):
@@ -258,7 +272,7 @@ class ResourceClosedError(InvalidRequestError):
     object that's in a closed state."""
 
 
-class NoSuchColumnError(KeyError, InvalidRequestError):
+class NoSuchColumnError(InvalidRequestError, KeyError):
     """A nonexistent column is requested from a ``Row``."""
 
 
@@ -431,8 +445,10 @@ class StatementError(SQLAlchemyError):
                 self.params,
                 self.orig,
                 self.hide_parameters,
+                self.__dict__.get("code"),
                 self.ismulti,
             ),
+            {"detail": self.detail},
         )
 
     @_preloaded.preload_module("sqlalchemy.sql.util")
@@ -571,8 +587,10 @@ class DBAPIError(StatementError):
                 self.orig,
                 self.hide_parameters,
                 self.connection_invalidated,
+                self.__dict__.get("code"),
                 self.ismulti,
             ),
+            {"detail": self.detail},
         )
 
     def __init__(