libzstd-kmp.so: Crash in Android release building using okhttp-zstd:5.3.2

[johnjohndoe]

Environment

• Galaxy Tab S7 FE, SM-T733, Android 14; Pixel 6, Android 16
• Sources: https://github.com/johnjohndoe/CampFahrplan/tree/fossgis-2026
  • Android Gradle Plugin 8.13.2
  • Kotlin 2.3.10
  • targetSdk 35
  • com.squareup.okhttp3:okhttp-zstd:5.3.2 (also happens with 5.4.0)

Steps to reproduce

1. Prepare some release keystore
2. Optionally add isDebuggable() to the release build type
3. Build a release version of the fossgis-2026 flavor
4. Install and run the app

Expected

• App fetches data and runs

Observed

• App fetches data and crashes
• Logs: adb-logs.txt

Fetch logs from a debug build

OkHttp        I  <-- 200 https://pretalx.com/fossgis2026/schedule/export/schedule.xml (1117ms)
OkHttp        I  access-control-allow-origin: *
OkHttp        I  alt-svc: h3=":443"; ma=2592000
OkHttp        I  content-encoding: zstd
OkHttp        I  content-security-policy: style-src 'self' 'unsafe-inline'; script-src 'self'; default-src 'self'; base-uri 'none'; img-src 'self' data:; form-action 'self'
OkHttp        I  content-type: text/xml
OkHttp        I  cross-origin-opener-policy: same-origin
OkHttp        I  date: Fri, 24 Jul 2026 11:57:03 GMT
OkHttp        I  etag: "1bbdcdc114ae556645d800a92173a209f929b49c-zstd"
OkHttp        I  referrer-policy: strict-origin-when-cross-origin
OkHttp        I  server: gunicorn
OkHttp        I  strict-transport-security: max-age=31536000; includeSubDomains; preload
OkHttp        I  vary: Cookie
OkHttp        I  vary: Accept-Encoding
OkHttp        I  via: 1.1 Caddy
OkHttp        I  x-content-type-options: nosniff
OkHttp        I  x-frame-options: DENY
OkHttp        I  <-- END HTTP
nativeloader  D  Load /data/app/~~0FFfM6a62T7TRZOZiPeDjw==/info.metadude.android.fossgis.schedule.debug-1Ykynrlv1D3tiajxtEU3og==/lib/arm64/libzstd-kmp.so using class loader ns clns-6 (caller=/data/app/~~0FFfM6a62T7TRZOZiPeDjw==/info.metadude.android.fossgis.schedule.debug-1Ykynrlv1D3tiajxtEU3og==/base.apk!classes31.dex): ok
FetchFahrplan D  ETag: '"1bbdcdc114ae556645d800a92173a209f929b49c-zstd"'
FetchFahrplan D  Last-Modified is missing
FetchFahrplan D  Fetch done successfully

Backend

• Pretalx 2026.3.0.dev0

Workaround

• Add the following ProGuard/R8 rules

-keepclasseswithmembers,includedescriptorclasses class com.squareup.zstd.** {
    native <methods>;
}
-keepclassmembers class com.squareup.zstd.** {
    <fields>;
}
-keepnames class com.squareup.zstd.**

Question

• Should theses rules be shipped with the artifact?

[JakeWharton]

Wrong project, but probably a dupe of square/zstd-kmp#108.

Also, for future reference, we are about to ban LLM use for code, issues, and comments. Please refrain from sending us walls of text when far less will do. Thanks!

[johnjohndoe]

Thank you for the pointer - I did not realize that there is another project.

I did not use AI to get the logs - I simply copied the output of adb. Since, c++ is not my expertise, I thought it might be helpful not to cut anything off for the analysis.