[.NET 10 Preview 1] System.IO.Compression.ZipArchive produces subtly incorrect zip headers

[jonathanpeppers]

Description

We noticed this here:

• [release/10.0.1xx-preview1] Update dependencies from dotnet/sdk android#9732
• 6c58f79...1da2ea4

We use System.IO.Compression.ZipArchive to create Android .apk files (and other archives).

When signing an .apk with Android's zipalign tool, it reports:

01-30 21:38:27.669 38611 159726 W zip     : WARNING: header mismatch 

However, if I inspect the actual file, some tools are ok with it:

> 7z t D:\Downloads\com.companyname.DotNetNewandroid.apk

7-Zip 24.09 (x64) : Copyright (c) 1999-2024 Igor Pavlov : 2024-11-29

Scanning the drive for archives:
1 file, 7069900 bytes (6905 KiB)

Testing archive: D:\Downloads\com.companyname.DotNetNewandroid.apk
--
Path = D:\Downloads\com.companyname.DotNetNewandroid.apk
Type = zip
Physical Size = 7069900

Everything is Ok

Files: 46
Size:       20333467
Compressed: 7069900

So, then we tried:

$ zipdetails com.companyname.DotNetNewandroid.apk
...
#
# ERROR: Found 1 Field Mismatch for Filename 'AndroidManifest.xml'
#
#  --------------------------------------------------------------------------------------
#  | Field Name       | Central Offset     | Central Value | Local Offset | Local Value | 
#  --------------------------------------------------------------------------------------
#  | Extract Zip Spec | 0x6BD1E2 (7066082) | 0x14 (20) 2.0 | 0x7 (7)      | 0x0 (0) 0.0 | 
#  --------------------------------------------------------------------------------------
#
# ERROR: Found 1 Field Mismatch for Filename 'res/layout/activity_main.xml'
#
#  --------------------------------------------------------------------------------------
#  | Field Name       | Central Offset     | Central Value | Local Offset | Local Value | 
#  --------------------------------------------------------------------------------------
#  | Extract Zip Spec | 0x6BD223 (7066147) | 0x14 (20) 2.0 | 0x460 (1120) | 0x0 (0) 0.0 | 
#  --------------------------------------------------------------------------------------
#
# ERROR: Found 1 Field Mismatch for Filename 'res/layout/layout.xml'
#
#  --------------------------------------------------------------------------------------
#  | Field Name       | Central Offset     | Central Value | Local Offset | Local Value | 
#  --------------------------------------------------------------------------------------
#  | Extract Zip Spec | 0x6BD26D (7066221) | 0x14 (20) 2.0 | 0x5C0 (1472) | 0x0 (0) 0.0 | 
#  --------------------------------------------------------------------------------------
#
# ERROR: Found 1 Field Mismatch for Filename 'res/mipmap-anydpi-v26/appicon.xml'
#
#  ----------------------------------------------------------------------------------------
#  | Field Name       | Central Offset     | Central Value | Local Offset   | Local Value | 
#  ----------------------------------------------------------------------------------------
#  | Extract Zip Spec | 0x6BD7A4 (7067556) | 0x14 (20) 2.0 | 0x779C (30620) | 0x0 (0) 0.0 | 
#  ----------------------------------------------------------------------------------------
#
# ERROR: Found 1 Field Mismatch for Filename 'res/mipmap-anydpi-v26/appicon_round.xml'
#
#  ----------------------------------------------------------------------------------------
#  | Field Name       | Central Offset     | Central Value | Local Offset   | Local Value | 
#  ----------------------------------------------------------------------------------------
#  | Extract Zip Spec | 0x6BD7F3 (7067635) | 0x14 (20) 2.0 | 0x78B0 (30896) | 0x0 (0) 0.0 | 
#  ----------------------------------------------------------------------------------------
#
# Error Count: 5

Full output: https://gist.github.com/grendello/3007335dba59383ac7782311d262e844

Reproduction Steps

• dotnet new android
• dotnet build

Xamarin.Android.Common.targets(2547,2): error ANDZA0000: 01-30 21:38:27.669 38611 159726 W zip     : WARNING: header mismatch 

Expected behavior

ZipArchive produces files that do not cause Android tooling to produce errors.

Actual behavior

ZipArchive produces files that cause Android tooling to produce errors.

Regression?

Yes

Known Workarounds

We are attempting a flag we have $(_AndroidUseLibZipSharp)=true, that will fall back to an open-source zip library we used to use.

Configuration

.NET SDK: 10.0.100-preview.1.25079.13
.NET runtime: 10.0.0-preview.1.25078.5

Archive: com.companyname.DotNetNewandroid.apk.zip

Other information

No response

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[carlossanlop]

@edwardneal seems there's a bug from the latest changes.

[jonathanpeppers]

It could be related to us using this file as input: packaged_resources.zip

A tool named aapt2 creates this original file.

Then we add additional files and save it to disk.

[carlossanlop]

Actually, it might not be a bug. We did change the logic that writes the zip headers, @jonathanpeppers . If the files are not malformed and can be read without issues, then maybe we need to let the tool know that the mismatch is expected this time.

[carlossanlop]

These were the changes introduced to System.IO.Compression.ZipArchive for preview1:

#103153
#102704
#111802

[jonathanpeppers]

then maybe we need to let the tool know that the mismatch is expected this time.

zipalign is not owned by us; it's part of Google's Android SDK and we have to shell out to it.

Some .zip tools can open the archive, but it's unknown yet if Android apps are installable and are able to run.

We are trying a workaround to see if this is blocking, thanks.

[carlossanlop]

If you open the archive with different tools, can you open the individual files and read their contents normally?

[jonathanpeppers]

Android Studio can open the file and view contents:

But because the "warning" message causes a build error, I don't know if it will run on Android yet.

[lewing]

for reference https://github.com/aosp-mirror/platform_build/blob/e8ac1cdd2583213911e91a990398e19c51002924/tools/zipalign/ZipEntry.cpp#L93