Improving the granularity parsing errors (#1623)

Add more context to GPBCodedInputStream failures.
Have GPBMessage parsing apis extract out the GPBCodedInputStream information and expose it.
Update HeaderDocs with pointers to all error domains/codes.
Expand the unittests to cover the full set of errors reported.

Fixes https://github.com/google/protobuf/issues/1618

1 files changed, 26 insertions, 2 deletions

diff --git a/objectivec/GPBMessage.h b/objectivec/GPBMessage.h
index 2249829f..b3b07793 100644
--- a/objectivec/GPBMessage.h
+++ b/objectivec/GPBMessage.h
@@ -49,12 +49,15 @@ extern NSString *const GPBMessageErrorDomain;
 
 /// Error code for NSError with GPBMessageErrorDomain.
 typedef NS_ENUM(NSInteger, GPBMessageErrorCode) {
-  /// The data being parsed is bad and a message can not be created from it.
-  GPBMessageErrorCodeMalformedData = -100,
+  /// Uncategorized error.
+  GPBMessageErrorCodeOther = -100,
   /// A message can't be serialized because it is missing required fields.
   GPBMessageErrorCodeMissingRequiredField = -101,
 };
 
+/// Key under which the error's reason is stored inside the userInfo dictionary.
+extern NSString *const GPBErrorReasonKey;
+
 CF_EXTERN_C_END
 
 /// Base class for all of the generated message classes.
@@ -86,6 +89,9 @@ CF_EXTERN_C_END
 /// @note In DEBUG builds, the parsed message is checked to be sure all required
 ///       fields were provided, and the parse will fail if some are missing.
 ///
+/// @note The errors returned are likely coming from the domain and codes listed
+///       at the top of this file and GPBCodedInputStream.h.
+///
 /// @param data     The data to parse.
 /// @param errorPtr An optional error pointer to fill in with a failure reason if
 ///                 the data can not be parsed.
@@ -101,6 +107,9 @@ CF_EXTERN_C_END
 /// @note In DEBUG builds, the parsed message is checked to be sure all required
 ///       fields were provided, and the parse will fail if some are missing.
 ///
+/// @note The errors returned are likely coming from the domain and codes listed
+///       at the top of this file and GPBCodedInputStream.h.
+///
 /// @param data              The data to parse.
 /// @param extensionRegistry The extension registry to use to look up extensions.
 /// @param errorPtr          An optional error pointer to fill in with a failure
@@ -119,6 +128,9 @@ CF_EXTERN_C_END
 /// @note In DEBUG builds, the parsed message is checked to be sure all required
 ///       fields were provided, and the parse will fail if some are missing.
 ///
+/// @note The errors returned are likely coming from the domain and codes listed
+///       at the top of this file and GPBCodedInputStream.h.
+///
 /// @param input             The stream to read data from.
 /// @param extensionRegistry The extension registry to use to look up extensions.
 /// @param errorPtr          An optional error pointer to fill in with a failure
@@ -139,6 +151,9 @@ CF_EXTERN_C_END
 ///       the required fields are set. So this method can be used to reload
 ///       messages that may not be complete.
 ///
+/// @note The errors returned are likely coming from the domain and codes listed
+///       at the top of this file and GPBCodedInputStream.h.
+///
 /// @param input             The stream to read data from.
 /// @param extensionRegistry The extension registry to use to look up extensions.
 /// @param errorPtr          An optional error pointer to fill in with a failure
@@ -158,6 +173,9 @@ CF_EXTERN_C_END
 /// @note In DEBUG builds, the parsed message is checked to be sure all required
 ///       fields were provided, and the parse will fail if some are missing.
 ///
+/// @note The errors returned are likely coming from the domain and codes listed
+///       at the top of this file and GPBCodedInputStream.h.
+///
 /// @param data     The data to parse.
 /// @param errorPtr An optional error pointer to fill in with a failure reason if
 ///                 the data can not be parsed.
@@ -171,6 +189,9 @@ CF_EXTERN_C_END
 /// @note In DEBUG builds, the parsed message is checked to be sure all required
 ///       fields were provided, and the parse will fail if some are missing.
 ///
+/// @note The errors returned are likely coming from the domain and codes listed
+///       at the top of this file and GPBCodedInputStream.h.
+///
 /// @param data              The data to parse.
 /// @param extensionRegistry The extension registry to use to look up extensions.
 /// @param errorPtr          An optional error pointer to fill in with a failure
@@ -188,6 +209,9 @@ CF_EXTERN_C_END
 ///       the required fields are set. So this method can be used to reload
 ///       messages that may not be complete.
 ///
+/// @note The errors returned are likely coming from the domain and codes listed
+///       at the top of this file and GPBCodedInputStream.h.
+///
 /// @param input             The stream to read data from.
 /// @param extensionRegistry The extension registry to use to look up extensions.
 /// @param errorPtr          An optional error pointer to fill in with a failure