Broken ZIP files created by commit a1da686

[AlyoshaVasilieva]

PR #290 (rev a1da686) appears to have broken writing, at least header writing. Creating test.zip by my example code in #287, tools report:

7-Zip:

Error: Headers Error
Unconfirmed start of archive

Warning: Headers Error
There are some data after the end of the payload data

zip -T test.zip (zip 3.0-11build1 on Ubuntu 20.04):

  error:  invalid compressed data to inflate testfile
test of test.zip FAILED

zip error: Zip file invalid, could not spawn unzip, or wrong unzip (original files unmodified)

Neither 7-Zip nor unzip can extract the archive created by this library.

The same code, when using rev 574bb3d, the immediately preceding commit, creates a working ZIP file.

[zamazan4ik]

@aweinstock314 check the issue please

[zamazan4ik]

@AlyoshaVasilieva I am sorry for the broken master branch. At least it shows that now we have lack of tests

[zamazan4ik]

If we do not fix the issue quickly - I will revert the corresponding PR.

[AlyoshaVasilieva]

No worries about broken master, better now than released.

I'm not good at writing CI but I'd recommend maybe creating test files and using zip -T command on a Linux runner to test them as a possible improvement to testing. It won't find everything (e.g. I think it doesn't care about wrong local headers if central record is fine) but it would detect broken files like here.

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edit: I investigated it a bit. It's writing 0 for both local csize and usize. Replacing those with 0xFFFFFFFF doesn't fix it, but tools will now get further. The new error from zip is:

$ zip -T test.zip
testfile               bad extra-field entry:
      EF block length (63 bytes) exceeds remaining EF data (24 bytes)
test of test.zip FAILED

zip error: Zip file invalid, could not spawn unzip, or wrong unzip (original files unmodified)

though the specific issue it points to might of course be wrong.

7-Zip gives "Unexpected end of data", "Headers Error", and a CRC error when extracting.

[n3vu0r]

I'm on it.

[zamazan4ik]

I have reverted the changes in master branch. So if you want to continue the work - please rebase :)

[lebe-dev]

Tested with different zip tools:

• 7-zip -> Warning: Header error
• Far Manager 3.x -> No warnings or errors
• Windows 10 Standard Zip tool -> No warnings\errors, but archive file is blank folder, no files present

[n3vu0r]

Does the fix as part of #292 pass your tests?

[zamazan4ik]

@AlyoshaVasilieva could you confirm please that with the latest release the issue is resolved? Thanks!

[AlyoshaVasilieva]

I believe it was fixed, will test again once I wake up

[AlyoshaVasilieva]

The test I've been using works fine with 0.6.2. Also works fine with the rejected PR #292.