Backend toolchain and inherited baseline

Status: P01-T01 evidence. Resolves D01 (runtime versions) for local/CI use; digests and remaining tool pins land in their owning P01 tasks. No Android version was changed.

1. Inherited Android baseline (observed, unchanged)

Source commit b8a52049e0294cd2d07612cedcc52b3017c5271e, branch main. gradle/libs.versions.toml: Kotlin 2.0.21, AGP 8.7.3, Compose BOM 2024.12.01, Room 2.6.1, Hilt 2.53.1, WorkManager 2.10.0, OkHttp 4.12.0, Jsoup 1.18.3. Gradle wrapper 8.10.2; minSdk 26, compileSdk/targetSdk 35; JVM target 17 (domain/application via jvmToolchain(17)); app versionName 3.1.0 / versionCode 4 (app/build.gradle.kts:42-43).

Execution environment on 2026-09-28:

• Active JVM: Eclipse Temurin 21 (java -version → 21+35-LTS). Gradle auto-provisioned Eclipse Temurin JDK 17.0.19+10 (/data/dev/caches/gradle-home/jdks/eclipse_adoptium-17-amd64-linux.2, ./gradlew -q javaToolchains → auto-detection/download enabled), which satisfies jvmToolchain(17). No JDK install or Gradle change was needed.
• Android SDK: ANDROID_HOME/ANDROID_SDK_ROOT = /data/dev/android/sdk/Sdk holds platforms/android-34, android-35, android-36, android-36.1 and build-tools/35.0.0 among others. The earlier "no platforms directory" observation inspected the parent symlink path /data/dev/android/sdk/platforms instead of $ANDROID_HOME.
• Full baseline ./gradlew :domain:test :application:test :data:testDebugUnitTest :app:testDebugUnitTest :app:assembleDebug --no-daemon → BUILD SUCCESSFUL in ~1m55s (88 tasks: 81 executed, 2 from cache, 5 up-to-date). bash scripts/validate-repo-baseline.sh → exit 0.

2. Backend toolchain pins (D01: decided)

• Go: minimum supported 1.26, preferred 1.27.x (checked 2026-09-28: latest 1.27.1 per go.dev; Go supports the two most recent majors). Installed go1.22.2 is out of support and must not be used beyond this planning task. P01-T02 pins the exact version in backend/go.mod (GOTOOLCHAIN=auto may fetch it; a local 1.26+ install is preferred).
• PostgreSQL 18 + PostGIS 3.6.x (stable 3.6.2, Feb 2026; supports PG 12–18; PG 14–18 are supported majors per postgresql.org). PostGIS 3.7 is still RC — do not use for the pilot. P01-T07 pins the exact image digest (no latest tags) in infra/compose.dev.yml.
• Docker 29.1.3 + Compose v2.27.0 (verified docker version server reachable, docker compose version). Daemon access confirmed.
• Go stack per ADR-005: net/http, chi routing, pgx, sqlc, slog, explicit SQL migrations. Exact library versions are pinned in backend/go.mod by P01-T02 with a recorded license/security review; Caddy image digest by P01-T10.
• Static/contract tooling (staticcheck, govulncheck, sqlc, OpenAPI linter) is pinned in P01-T11/P01-T12, not here.

3. Licenses and support

Go BSD-3-Clause; PostgreSQL under the permissive PostgreSQL Licence; PostGIS GPL-2.0 (copyleft — server-side use, no client redistribution); Docker Engine/Compose Apache-2.0; Gradle/AGP Apache-2.0; Room/Compose/WorkManager Apache-2.0. Support windows rechecked 2026-09-28 via go.dev, postgresql.org and postgis.net; recheck at image/dependency procurement (P01-T02/T07).

4. Inherited documentation corrections (A01/A02/A11)

Baseline truth; docs/architecture.md R-ARCH-03 and the README scope/version lines below are corrected in this task. Remaining historical references (tech-stack/data-sources/ADR-001 FTS5 prose, old TABELA-ANP-COMBUSTIVEIS URLs, docs/releases/v1.0.0|v2.0.0.md) stay as history and are recorded here, not rewritten.

• A01 — FTS baseline is FTS4. MunicipalityFtsEntity.kt:5,14 uses Room @Fts4; AnpFuelDatabaseMigrations.kt:12,102 create municipality_fts USING FTS4. Prose claiming FTS5 (docs/architecture.md:285,331-338, docs/tech-stack.md:17,34,105,188,191, docs/data-sources.md:121, docs/adr/001-kotlin-compose-stack.md:27,37) is stale. Do not replace search during backend work.
• A02 — Schema v4; :data also depends on :application. AnpFuelDatabase.kt:30 → version = 4 with schemas 1–4 under data/schemas/; data/build.gradle.kts:57-58 implements both project(":domain") and project(":application") (worker orchestration). docs/architecture.md R-ARCH-03 and its version-1 schema example are corrected/annotated accordingly in this task.
• A11 — Legacy publishing references. README.md indexed UC-001…UC-014 while UC-015 exists (FindNearestBestPriceStationUseCase, architecture mapping table row UC-015); linked git-ignored .local/PROJECT_PLAN.md; release quick-start commented (v2.0.0) while the release is 3.1.0 (app/build.gradle.kts:42-43). Scope/version lines are corrected in this task; historical release notes keep their original text. Never run release/tag scripts to establish a baseline.

5. Validation evidence

java -version  # Temurin 21+35-LTS (launcher); JDK 17.0.19 auto-provisioned by Gradle
go version     # go1.22.2 linux/amd64 — out of support, plan-only
docker version # Server 29.1.3 reachable
docker compose version  # v2.27.0
bash scripts/validate-repo-baseline.sh  # exit 0
./gradlew :domain:test :application:test :data:testDebugUnitTest \
  :app:testDebugUnitTest :app:assembleDebug --no-daemon  # BUILD SUCCESSFUL ~1m55s
./gradlew -q javaToolchains --no-daemon  # Temurin 17.0.19 provisioned; 21 current
git diff --check  # clean (run after edits)

Limitation: instrumentation (connectedDebugAndroidTest), coverage/lint gates and live ANP import were not executed in this task.

6. Next

P01-T02 (Go module and process roots) consumes the Go ≥1.26 pin from §2. P01-T07 pins the Postgres/PostGIS digest. Backend code starts in P01-T02; no Android source was touched here.