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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Empty read from gitdb.OStream.read() before EOF","articleBody":"I have code that relies on reading an object from a gitdb stream.\n\nTo do this I used with a standard `.read()` loop (like with [io.RawIOBase](https://docs.python.org/3/library/io.html#io.RawIOBase)):\n\n```python\nstream = db.stream(bytes.fromhex(sha))\nwhile chunk := stream.read(4096):\n    yield chunk\n```\n\nThe behaviour I expected to see (from the duck-type with RawIOBase) is to only see `b''` at EOF:\n\n\u003e If 0 bytes are returned, and size was not 0, this indicates end of file. \n\nHowever `stream.read(4096)` can return empty chunks even before the end of the stream, so the loop exits early.\n\nFor the file where I saw this first, it is sensitive to the `size` parameter - it apparently occurs for `0 \u003c size \u003c= 4096`.\n\nLooking at the code there is a condition to repeat a read if we got insufficient bytes:\n\nhttps://github.com/gitpython-developers/gitdb/blob/f36c0cc42ea2f529291e441073f74e920988d4d2/gitdb/stream.py#L316-L317\n\nHowever the leading `if dcompdat and ` means that the condition doesn't apply if zero bytes were read. Removing this part of the condition addresses the issue (but I understand from the comment that this is in order to support `compressed_bytes_read()`).","author":{"url":"https://github.com/lordmauve","@type":"Person","name":"lordmauve"},"datePublished":"2025-04-16T10:35:10.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/120/gitdb/issues/120"}