Fix encoding 0-length arrays #225
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The array encoder assumed that arrays had at least one value, so it would serialize them with a zero-value for the array, such as `[0]`. This adds a test to reproduce the issue, and updates the encoder to write an empty array if the length is 0.
feature_reflect_array.go
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| func (encoder *arrayEncoder) Encode(ptr unsafe.Pointer, stream *Stream) { | ||
| if encoder.arrayType.Len() == 0 { |
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Looking at this again I realized that since an array's length is a static part of the type, I could also move this into encoderOfArray to return a special emptyArrayEncoder instead of checking the length on each value. That would be faster and also fix some assumptions in EncodeInterface and IsEmpty that the array has a non-zero length.
I don't quite understand the special optimization for interface{} in EncodeInterface and when that case would get called. The output in that case is hard-coded to produce [null], but it seems like that also ignores the original length of the array, even if the contents should all be null.
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emptyArrayEncoder sounds like a good idea, can you make it happen?
Codecov Report
@@ Coverage Diff @@
## master #225 +/- ##
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- Coverage 83.86% 83.72% -0.14%
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Files 42 42
Lines 5416 5426 +10
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+ Hits 4542 4543 +1
- Misses 690 697 +7
- Partials 184 186 +2
Continue to review full report at Codecov.
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Instead of checking the array length in encode, this can be checked up front in `encoderOfArray` since the array type has a fixed length determined at compile time. So return an `emptyArrayEncoder` that simply writes an empty array to the stream.
Fix encoding 0-length arrays
2 participants
The array encoder assumed that arrays had at least one value, so it
would serialize them with a zero-value for the array, such as
[0].This adds a test to reproduce the issue, and updates the encoder to
write an empty array if the length is 0.