Make sure copied files actually have write permissions in ~/.openshot-qt

[peti]

openshot-qt copies all kinds of Python or SVG files into a temporary location, i.e.~/.openshot_qt/blender/8f9c347a-ce4e-11e9-b006-a4c3f0b51071/lens_flare.py. Now, on the NixOS those files are installed with 0444 permissions. The originals have no +w bit -- and consequently the copy lacks that permission and cannot be used properly by the edit. This trivial problem breaks the title generator on NixOS, among other things (NixOS/nixpkgs#48591).

Would you consider adding code into oneshot-qt that simply performs a chmod u+w on the newly created temporary file after copying it?

[ferdnyc]

@peti The interesting thing is, we're not creating that file as a copy of the source. We're reading the source file into memory, then writing it out to a newly-created file. So, the permissions of the original shouldn't matter, I don't think. If it's being created read-only, I suspect it probably has something to do with the umask on your system. (Out of curiosity, are the .png files created by Blender also read-only?)

Whatever the reason, I've submitted #2973 with a change to explicitly set write permission on the generated .py file after it's created. That should hopefully ensure that the file is made writable on all three OSes.

[ferdnyc]

Aagh! Never mind, I was wrong. We do copy the file first, before modifying it.

But that actually makes things even easier, we can use Python's shutil.copyfile() instead of shutil.copy(), to copy the file without duplicating its permissions. Ignore that AppImage, I'm going to update the PR to fix both the animated and still title file copying.

[ferdnyc]

OK, #2973 should now fix both the .svg files and the .py files. Don't worry about testing it, though, as the AppImage won't be a valid test anymore ­— its template files are most likely not set read-only.

However, if you want to attempt a local fix, the fix is as simple as changing shutil.copy() to shutil.copyfile() in both openshot_qt/windows/views/blender_listview.py and openshot_qt/windows/title_editor.py in your OpenShot install.

[peti]

I applied the patch in NixOS (NixOS/nixpkgs@d7bbcdf) and the new version appears to work fine. Thank you very much for the quick fix!

[ferdnyc]

Glad to hear that worked! Reopening this only because the fix hasn't gone in yet on our end; GitHub will auto-close when the PR gets merged.