CI has only ever produced debug-signed Android artifacts, because
build.gradle.kts:63-70 falls back to signingConfigs "debug" when
key.properties is absent, which is exactly the CI condition (#111).
Debug-signed builds cannot be installed over a Play install or over a
properly signed GitHub release, so users hit "App not installed".
Adds a separate workflow that signs with the real keystore.
Security posture, given this repo is PUBLIC and the keystore is the one
credential that cannot be replaced if leaked:
- No pull_request trigger. A PR, including from a fork, must never run
a job that can read these secrets.
- Pinned to the release-signing Environment, which carries a required
reviewer and only accepts main or v* tags. The signing secrets are
scoped to that environment, NOT to the repo, so a workflow that
omits the environment key cannot read them at all.
- Keystore decoded to disk only for the build, removed in a step with
if: always() so a failed build leaves nothing behind.
- Secrets passed via env: and printf'd into a file, never placed on a
command line where they would appear in process listings, and never
echoed.
Includes an apksigner check that fails the job if the built APK carries
CN=Android Debug. A green build alone does not prove release signing,
because the gradle fallback is silent; that check is what makes this
verifiable rather than assumed.
The keystore is PKCS12 despite its .jks extension, and PKCS12 cannot
carry a key password distinct from the store password, so one secret
correctly populates both fields.
Part of epic #312, plan #321 (Phase 5).
Strycher
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