Fix NullPointerException issues in HeifReader and PngMetadataReader #708
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- Add null checks in HeifReader.extract() and PngMetadataReader.readMetadata() - Handle InputStream.available() edge case in HeifReader - Add @NotNull annotations for API clarity - Add unit tests for null parameter handling
drewnoakes
reviewed
Oct 5, 2025
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| int available = inputStream.available(); | ||
| // Some InputStreams return -1 for available(), so use a reasonable default | ||
| int markReadAheadLimit = (available > 0) ? available + 1 : 8192; | ||
| inputStream.mark(markReadAheadLimit); |
Owner
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Is there some additional context on this change? In what case were you seeing this? I'd like to think through the consequences of this a bit more.
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| if (inputStream == null) { | ||
| throw new IllegalArgumentException("inputStream cannot be null"); | ||
| } | ||
| if (handler == null) { | ||
| throw new IllegalArgumentException("handler cannot be null"); | ||
| } |
Owner
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There are probably thousands of such places where we don't validate parameter values as non-null. I'm not sure what value this adds in practice.
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| public void extract(InputStream inputStream, HeifHandler<?> handler) | ||
| public void extract(@NotNull InputStream inputStream, @NotNull HeifHandler<?> handler) |
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Problem
Fixes
java.lang.NullPointerExceptionin stream reader initialization chain, particularly affecting HEIF and PNG metadata reading workflows.Root Cause: Missing null parameter validation in key entry points allows null InputStreams to propagate through the system, causing NPEs during StreamReader construction or method chaining.
Solution
inputStreamandhandlerparametersInputStream.available()edge case handling@NotNullannotations for better IDE supportChanges Made
HeifReader.extract()
inputStream != nullandhandler != nullIllegalArgumentExceptionwith descriptive messagesInputStream.available()handling when it returns -1PngMetadataReader.readMetadata()
Testing
HeifReaderTestwith 3 comprehensive test scenarios:Impact
@NotNullannotations help developers use the API correctly