read_xmp Crashes python without exception about pyexiv2 HOT 8 CLOSED

Thanks for your report.
When I'm using your images auphofBSF@3890a83, I can call .read_exif() and .read_iptc() normally, but calling .read_xmp() always causes Python to crash.
The good news is that this problem can be repeated. I'll start debugging it now.

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By the way, I used to compile exiv2 with VS2015, but the latest exiv2 project can only be compiled with VS2017.

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Sounds like a tricky bug, your commit makes it at least work sometimes for more than 1 read but unfortunately it still fails for me with Python Crash after an seemingly unpredictable number of reads. sorry I cant contribute more to the cpp debugging

In my test I have a folder of 43 Nikon images processed by Digikam.
The following code Fails at random number of iterations, 7,16,19,12,6,10,3 (no pattern evident). It has never processed all 43.

from os import listdir
from os.path import isfile, join
files = [f for f in listdir(mypath) if isfile(os.path.join(mypath, f))]

for i,f in enumerate(files):
    image = Image(os.path.join(mypath, f))
    try:
        xmpDict = image.read_xmp()
        print('{} | Image: {}  Xmp.digiKam.TagsList: {}  Xmp.dc.subject: {}   -----------------'.format(i, image.filename,
                xmpDict['Xmp.digiKam.TagsList'],
                xmpDict['Xmp.dc.subject']))

    #     xmpDictNew = xmpDict.copy()
    #     xmpDictNew['Xmp.dc.subject'] = xmpDict['Xmp.digiKam.TagsList']
    #     xmpDictNew['Xmp.dc.subject'] = "TEST"
    #     # image.modify_xmp(xmpDictNew)
    except Exception as e:
        print("Error:{}".format(e))

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I changed a little code, rebuilt, and then successfully read XMP.
commit 715ce1d
Please confirm whether the problem has been solved.

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Yesterday, I tried to do this on Linux, and it reads normally. But doing this on Windows would cause Python to crash.

When calling the read_*() method, Python will call the C++ API, and the C++ API wil read the metadata and return it to Python.
Since there are many data need to be returned, I use an EOL symbol to separate them.

What confuses me is that:

• When EOL is set to "\n\r", reading metadata will randomly causes the program to crash. Sometimes it crashes during the reading, sometimes after a reading, and sometimes during a repeated reading.
• When EOL is set to "\n \r" (just add a space), I can read 1000 times in 10 seconds with no problem.

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Random crashes are usually caused by memory exceptions.
This problem seems to be caused by the use of local variables outside of scope, like this:

std::stringstream data;
data << "some data...";
make_buffer(data.str());
// the data which data.str() returns, may have been destroyed when the function make_buffer() reads it

I have corrected the use of stringstream.str(), and now none of the previous problems would be repeated on my computer.
commit 028f6418

Please confirm whether the problem has been solved.

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Fantastic, @LeoHsiao1, I've learnt a lot and this now works well for the test case of 42 images. Well done. I am happy to mark this issue closed

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This issue has been automatically closed because there has been no activity for a month.

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