F-041: spike Bazel BUILD generate/check from forma model

README.md

@@ -52,6 +52,7 @@ systems like Buck and Bazel.
 9. [JVM targets](docs/JVM-TARGETS.md) — pure JVM platform plugin `tools.forma.jvm` (F-030)
 10. [JVM sample application](docs/JVM-SAMPLE.md) — multi-module pure-JVM gold standard (`jvm-application/`, F-031)
 11. [Bazel adapter design](docs/BAZEL-ADAPTER.md) — target types to rules, restriction graph to visibility (F-040 design)
+12. [Bazel adapter spike](bazel-adapter/README.md) — generate/check BUILD from Forma model (F-041; JVM-first)
 
 Configuration made easy:
 
@@ -208,6 +209,7 @@ Pure JVM target set (`tools.forma.jvm`, `JvmTargetRegistry`): **F-030** done (se
 JVM sample application + `binary` composition root: **F-031** done ([`docs/JVM-SAMPLE.md`](docs/JVM-SAMPLE.md), `jvm-application/`).
 JVM getting-started tutorial: **F-032** done ([`docs/JVM-GETTING-STARTED.md`](docs/JVM-GETTING-STARTED.md)).
 Bazel adapter mapping design (targets ↔ rules, visibility ↔ deps): **F-040** done (see [`docs/BAZEL-ADAPTER.md`](docs/BAZEL-ADAPTER.md)).
+Bazel adapter spike (generate/check BUILD from portable model, JVM matrix): **F-041** done ([`bazel-adapter/`](bazel-adapter/), spike results in BAZEL-ADAPTER.md).
 
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TICKETS.md

@@ -49,7 +49,7 @@ Update this file when picking or finishing work. Cron workers must pick the **hi
 | ID | Status | Title | Notes |
 |----|--------|-------|-------|
 | F-040 | done | Design Bazel adapter mapping (targets ↔ rules, visibility ↔ deps) | `docs/BAZEL-ADAPTER.md` + cross-links; commit 45674c7 |
-| F-041 | todo | Spike: generate or check Bazel BUILD from forma declarations | |
+| F-041 | done | Spike: generate or check Bazel BUILD from forma declarations | `bazel-adapter/` generate+check via core RestrictionGraph; examples + tests green |
 | F-042 | todo | Minimal Bazel sample using forma-core concepts | |
 
 ## Backlog (lower priority / historical GitHub)

bazel-adapter/README.md

@@ -0,0 +1,43 @@
+# bazel-adapter (F-041 spike)
+
+JVM-first adapter that converts a portable `FormaProjectModel` (targets + declared edges) into Bazel `BUILD.bazel` fragments (or validates them) while preserving the forma-core `RestrictionGraph` discipline.
+
+**Core invariant:** `impl` may never depend on another `impl`; composition happens only at `binary`. The adapter enforces this using `RestrictionGraph.isAllowed` from `tools.forma:core`.
+
+## What it contains
+
+- `tools.forma.bazel.model.*` — portable snapshot types (no Gradle APIs)
+- `JvmBazelAdapter` implementing `FormaToBazel.generate()` + `check()`
+- Hand-built fixture from `jvm-application/` (8 targets)
+- Unit tests + committed example BUILD files under `examples/`
+
+## Running
+
+Requires JDK 17+ (Temurin recommended).
+
+```bash
+# From repo root
+source scripts/env-mac.sh
+
+cd bazel-adapter
+./gradlew test
+./gradlew runSample   # prints generated BUILD text + check report
+```
+
+You do **not** need Bazel installed for the spike.
+
+## Limitations (spike)
+
+- Only JVM 6-type matrix (`jvm.api` ... `jvm.binary`)
+- Project edges only (no external catalog GAV translation)
+- Visibility is computed from declared consumers in the model + graph (hybrid; good enough)
+- No full BUILD parser — check validates the *model* edges (and lightly inspects generated text)
+- No `kt_jvm_test` emission yet (testDependencies carried in model but ignored for rule emission)
+- No content rules (pure JVM has none)
+
+## Golden / committed artifacts
+
+- `examples/jvm-application-build/` — representative generated BUILD.bazel files
+- Tests assert key labels, absence of illegal edges, round-trip cleanliness
+
+See `docs/BAZEL-ADAPTER.md` for the full mapping design and F-041 acceptance criteria.

bazel-adapter/build.gradle.kts

@@ -0,0 +1,42 @@
+plugins {
+    kotlin("jvm")
+}
+
+// Co-version with forma; for spike we do not publish the adapter.
+group = "tools.forma.experimental"
+version = "0.1.3-spike"
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(17))
+    }
+}
+
+kotlin {
+    jvmToolchain(17)
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    // ONLY production dependency allowed per F-041 / BAZEL-ADAPTER design:
+    // adapter depends on core; core has ZERO Bazel / Gradle-Project / AGP knowledge.
+    implementation("tools.forma:core:0.1.3")
+
+    // Test only
+    testImplementation(kotlin("test"))
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+
+// Convenience: allow running a small main to dump sample output if added later
+tasks.register<JavaExec>("runSample") {
+    group = "application"
+    description = "Run a driver that prints generated BUILD for the jvm-application fixture"
+    mainClass.set("tools.forma.bazel.BazelAdapterSampleKt")
+    classpath = sourceSets["main"].runtimeClasspath
+}

bazel-adapter/examples/jvm-application-build/binary/BUILD.bazel

@@ -0,0 +1,22 @@
+# GENERATED by JvmBazelAdapter (F-041) — do not edit by hand for the spike.
+# gradlePath=:binary type=jvm.binary
+
+kt_jvm_binary(
+    name = "binary",
+    srcs = glob(["src/main/kotlin/**/*.kt"]),
+    deps = [
+        "//common/library:library",
+        "//common/util:util",
+        "//feature/calculator/api:api",
+        "//feature/calculator/impl:impl",
+        "//feature/greeter/api:api",
+        "//feature/greeter/impl:impl",
+    ],
+    visibility = [
+        "//visibility:public",
+    ],
+    main_class = "tools.forma.jvm.sample.binary.MainKt",
+    tags = [
+        "forma:type=jvm.binary",
+    ],
+)

bazel-adapter/examples/jvm-application-build/feature/greeter/api/BUILD.bazel

@@ -0,0 +1,14 @@
+# GENERATED by JvmBazelAdapter (F-041) — do not edit by hand for the spike.
+# gradlePath=:feature:greeter:api type=jvm.api
+
+kt_jvm_library(
+    name = "api",
+    srcs = glob(["src/main/kotlin/**/*.kt"]),
+    visibility = [
+        "//binary:__pkg__",
+        "//feature/greeter/impl:__pkg__",
+    ],
+    tags = [
+        "forma:type=jvm.api",
+    ],
+)

bazel-adapter/examples/jvm-application-build/feature/greeter/impl/BUILD.bazel

@@ -0,0 +1,18 @@
+# GENERATED by JvmBazelAdapter (F-041) — do not edit by hand for the spike.
+# gradlePath=:feature:greeter:impl type=jvm.impl
+
+kt_jvm_library(
+    name = "impl",
+    srcs = glob(["src/main/kotlin/**/*.kt"]),
+    deps = [
+        "//common/library:library",
+        "//common/util:util",
+        "//feature/greeter/api:api",
+    ],
+    visibility = [
+        "//binary:__pkg__",
+    ],
+    tags = [
+        "forma:type=jvm.impl",
+    ],
+)

bazel-adapter/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists