[sql] Framework for allowing tests to handle errors.

sql/connection.h

Index: sql/connection.h
diff --git a/sql/connection.h b/sql/connection.h
index 049d7cf5b4e2f9715ffc4b7f67dd2e89dc367bff..c5ab91b74223fc70dc8e618b5c472857864d428b 100644
--- a/sql/connection.h
+++ b/sql/connection.h
@@ -539,6 +539,54 @@ class SQL_EXPORT Connection {
   DISALLOW_COPY_AND_ASSIGN(Connection);
 };
 
+// Most errors are fatal in debug mode, because usually they indicate
+// an inappropriate use of SQL.  This makes it challenging to write
+// tests for things like recovery from corruption.  Use this scoper to
+// ignore errors during the current test.  This applies globally (to
+// all connections).  The scoper can be nested, but is not thread-safe.
+//
+// Specific errors must be ignores, and all ignored errors must be

[erikwright (departed), 2013/06/11 18:54:19]

Grammar problems to the point that I don't know what this line means.

+// seen.
+//
+// TODO(shess): Wire things up so this can only be used from tests.
+// NOTE(shess): This does not comprehensively suppress errors at this
+// time.  If your test is handling database errors and you're hitting
+// a case not handled, contact me.
+// NOTE(shess): If you use this in production code, I will revert you.
+class SQL_EXPORT ScopedErrorIgnorer {

[erikwright (departed), 2013/06/11 18:54:19]

I'd have to scan sql/ to see what the local convention is, but I'm a big fan of
one class per file and would prefer to see this moved into
sql/scoped_error_ignorer.h, for example.

+ public:
+  ScopedErrorIgnorer();
+  ~ScopedErrorIgnorer();
+
+  // Add an error to ignore.  Extended error codes can be ignored
+  // specifically, or the base can be ignored as a group
+  // (SQLITE_IOERR_* versus SQLITE_IOERR).
+  void IgnoreError(int err);
+
+  // Allow containing test to check if the errors were encountered.
+  // Test is REQUIRED to call this before destruction.
+  // TODO(shess): How to handle ASSERT_X() cases which cause early
+  // return in tests?
+  bool CheckIgnoredErrors();
+
+  // Check if the error should be ignored.
+  static bool ShouldIgnoreError(int err);
+
+ private:
+  // Record whether CheckIgnoredErrors() has been called.
+  bool checked_;
+
+  // Errors to ignore.
+  std::set<int> ignore_errors_;
+
+  // Errors which have been ignored.
+  std::set<int> errors_ignored_;
+
+  ScopedErrorIgnorer* next_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedErrorIgnorer);
+};
+
 }  // namespace sql
 
 #endif  // SQL_CONNECTION_H_