Make sure we propagate TLV decode errors to consumers in Darwin frame…

…work. (#26890)

In particular, in MTRDevice we should cache that we had a decode failure instead
of leaving the cache un-filled.

src/darwin/Framework/CHIP/MTRBaseDevice.mm

@@ -574,7 +574,7 @@ id _Nullable MTRDecodeDataValueDictionaryFromCHIPTLV(chip::TLV::TLVReader * data
  chip::TLV::Tag tag = data->GetTag();
  id value = MTRDecodeDataValueDictionaryFromCHIPTLV(data);
  if (value == nullptr) {
- MTR_LOG_ERROR("Error when decoding TLV container");
+ MTR_LOG_ERROR("Error when decoding TLV container of type %s", typeName.UTF8String);
  return nil;
  }
  NSMutableDictionary * arrayElement = [NSMutableDictionary dictionary];

src/darwin/Framework/CHIP/MTRDevice.mm

@@ -1356,14 +1356,16 @@ - (void)invokeCommandWithEndpointID:(NSNumber *)endpointID
  MTRErrorKey : [MTRError errorForCHIPErrorCode:CHIP_ERROR_INVALID_ARGUMENT]
  }];
  } else {
- id value;
- if (apData == nullptr) {
- value = nil;
+ id value = MTRDecodeDataValueDictionaryFromCHIPTLV(apData);
+ if (value == nil) {
+ MTR_LOG_ERROR("Failed to decode event data for path %@", eventPath);
+ [mEventReports addObject:@ {
+ MTREventPathKey : eventPath,
+ MTRErrorKey : [MTRError errorForCHIPErrorCode:CHIP_ERROR_DECODE_FAILED],
+ }];
  } else {
- value = MTRDecodeDataValueDictionaryFromCHIPTLV(apData);
+ [mEventReports addObject:[MTRBaseDevice eventReportForHeader:aEventHeader andData:value]];
  }
-
- [mEventReports addObject:[MTRBaseDevice eventReportForHeader:aEventHeader andData:value]];
  }
 }
 
@@ -1391,7 +1393,13 @@ - (void)invokeCommandWithEndpointID:(NSNumber *)endpointID
  }];
  } else {
  id value = MTRDecodeDataValueDictionaryFromCHIPTLV(apData);
- if (value) {
+ if (value == nil) {
+ MTR_LOG_ERROR("Failed to decode attribute data for path %@", attributePath);
+ [mAttributeReports addObject:@ {
+ MTRAttributePathKey : attributePath,
+ MTRErrorKey : [MTRError errorForCHIPErrorCode:CHIP_ERROR_DECODE_FAILED],
+ }];
+ } else {
  [mAttributeReports addObject:@ { MTRAttributePathKey : attributePath, MTRDataKey : value }];
  }
  }

src/darwin/Framework/CHIP/MTRError.h

@@ -69,6 +69,13 @@ typedef NS_ERROR_ENUM(MTRErrorDomain, MTRErrorCode){
  * expected schema.
  */
  MTRErrorCodeSchemaMismatch MTR_NEWLY_AVAILABLE = 13,
+ /**
+ * MTRErrorCodeTLVDecodeFailed means that the TLV being decoded was malformed in
+ * some way. This can include things like lengths running past the end of
+ * the buffer, strings that are not actually UTF-8, and various other
+ * TLV-level failures.
+ */
+ MTRErrorCodeTLVDecodeFailed MTR_NEWLY_AVAILABLE = 14,
 };
 // clang-format on
 

src/darwin/Framework/CHIP/MTRError.mm

@@ -89,6 +89,9 @@ + (NSError *)errorForCHIPErrorCode:(CHIP_ERROR)errorCode
  [userInfo addEntriesFromDictionary:@{
  NSLocalizedDescriptionKey : NSLocalizedString(@"The device is already a member of this fabric.", nil)
  }];
+ } else if (errorCode == CHIP_ERROR_DECODE_FAILED) {
+ code = MTRErrorCodeTLVDecodeFailed;
+ [userInfo addEntriesFromDictionary:@{ NSLocalizedDescriptionKey : NSLocalizedString(@"TLV decoding failed.", nil) }];
  } else {
  code = MTRErrorCodeGeneralError;
  [userInfo addEntriesFromDictionary:@{