F-022: extract validation framework into plugins/core

README.md

@@ -197,6 +197,7 @@ Configuration-time performance: **F-017**
 ([`docs/CONFIGURATION-PERFORMANCE.md`](docs/CONFIGURATION-PERFORMANCE.md)).
 forma-core API design: **F-020** ([`docs/forma-core-api.md`](docs/forma-core-api.md)).
 forma-core extraction (restriction engine + TargetType + Android matrix kit): **F-021** done (`plugins/core`).
+forma-core validation SPI + content rules (Gradle facade in `:validation`): **F-022** done.
 
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TICKETS.md

@@ -32,7 +32,7 @@ Update this file when picking or finishing work. Cron workers must pick the **hi
 |----|--------|-------|-------|
 | F-020 | done | Design forma-core public API (types, restrictions, validation, target registry) | `docs/forma-core-api.md` — types, restriction graph, validator SPI, registry, coords, library-suffix decision |
 | F-021 | done | Extract dependency-type / restriction engine into `forma-core` | `plugins/core` + TargetType/NameMatcher/RestrictionGraph + AndroidTargetTypes + AndroidRestrictionKit (distinct jvm.library vs android.library); facades preserved. Related GH #39 |
-| F-022 | todo | Extract validation framework into `forma-core` | Keep Android validators as plugins |
+| F-022 | done | Extract validation framework into `forma-core` | `plugins/core` TargetValidator + ContentRule; `:validation` facade; Android helpers call pure rules |
 | F-023 | todo | Wire Android implementation as first consumer of forma-core | Sample still builds |
 | F-024 | todo | Publish/coordinate coordinates: `tools.forma:core` vs android plugins | |
 

docs/ARCHITECTURE.md

@@ -70,17 +70,18 @@ Group/version (root `plugins/build.gradle.kts`): **`tools.forma` / `0.1.3`**.
 
 ```
                     ┌────────────┐
-                    │    core    │  TargetType, NameMatcher, RestrictionGraph (F-021)
+                    │    core    │  TargetType, RestrictionGraph (F-021),
+                    │            │  TargetValidator + ContentRule (F-022)
                     └─────▲──────┘
                           │
                     ┌─────┴──────┐
-                    │   target   │  TargetTemplate, FormaTarget (parallel for compat)
+                    │   target   │  TargetTemplate; FormaTarget : TargetRef
                     └─────▲──────┘
                           │
               ┌───────────┼────────────┐
               │           │            │
         ┌─────┴─────┐ ┌───┴────┐       │
-        │validation │ │ owners │       │
+        │validation │ │ owners │       │  validation = Gradle facade over core
         └─────▲─────┘ └───▲────┘       │
               │           │            │
         ┌─────┴─────┐     │      ┌─────┴─────┐
@@ -90,19 +91,19 @@ Group/version (root `plugins/build.gradle.kts`): **`tools.forma` / `0.1.3`**.
               └─────┬─────┴────────────┘
                     │
               ┌─────┴─────┐
-              │  android  │  user-facing DSL + AGP features (+ AndroidTargetTypes + matrix)
+              │  android  │  DSL + AGP + AndroidTargetTypes + matrix + content helpers
               └───────────┘
 ```
 
 | Module | Plugin id | Depends on | Responsibility |
 |--------|-----------|------------|----------------|
-| `:core` | (library, not plugin) | (none / gradleApi compileOnly if needed) | `TargetType` / `TargetRef`, `NameMatcher`/`SuffixNameMatcher`, `RestrictionGraph`/`MutableRestrictionGraph`, `EdgeKind`, `RestrictionRule`. Pure engine. |
-| `:target` | `tools.forma.target` | `gradleApi` | `TargetTemplate(suffix)`, `FormaTarget(project)` (compat facade; F-021 adds parallel core types) |
-| `:validation` | `tools.forma.validation` | `:target`, `gradleApi` | Name validators, content validators, `ProjectValidationError` (F-022 will migrate to core) |
+| `:core` | (library, not plugin) | (none) | Pure engine: `TargetType`/`TargetRef`, `NameMatcher`, `RestrictionGraph`, **`TargetValidator` / `dependencyTypeValidator` / `selfTypeValidator` / `AcceptAny`**, **`ContentRule` + No/OnlyResources/OnlyLayout**, `FormaValidationException`. Identity-cached factories (F-017). |
+| `:target` | `tools.forma.target` | `:core`, `gradleApi` | `TargetTemplate(suffix)`; `FormaTarget(project)` implements `TargetRef` |
+| `:validation` | `tools.forma.validation` | `:core`, `:target`, `gradleApi` | Thin Gradle facade: legacy `Validator`/`validator(TargetTemplate…)` → core; `ProjectValidationError`; `validateDirectoryContent` (FS listing) |
 | `:owners` | `tools.forma.owners` | `gradleApi` | `Owner` / `Person` / `Team` / `NoOwner` |
 | `:config` | `tools.forma.config` | `gradleApi` | `AndroidProjectSettings`, `FormaSettingsStore`, plugin/dep registration maps |
-| `:deps` | `tools.forma.deps` | `:validation`, `:target`, `:config`, kotlin-dsl | `FormaDependency` model, `applyDependencies`, version-catalog generators |
-| `:android` | `tools.forma.android` | `:core` + all of the above + **AGP** + Kotlin GP | Target DSL (`api`, `impl`, `androidLibrary`, …), feature appliers; owns `AndroidTargetTypes` + `AndroidRestrictionKit` (F-021) |
+| `:deps` | `tools.forma.deps` | `:core`, `:validation`, `:target`, `:config`, kotlin-dsl | `FormaDependency` model, `applyDependencies`, version-catalog generators |
+| `:android` | `tools.forma.android` | `:core` + all of the above + **AGP** + Kotlin GP | Target DSL; `AndroidTargetTypes` + `AndroidRestrictionKit` (F-021); content helpers call core `ContentRule` (F-022) |
 
 `:android` compiles against **AGP 8.1.2** (aligned with sample runtime force in
 `application/settings.gradle.kts` as of F-003). Keep `plugins/android` AGP
@@ -307,9 +308,9 @@ Aligned with `docs/VISION.md`: core must not assume Android/AGP/Dagger.
 
 | Concern | Current home | forma-core? | Notes |
 |---------|--------------|-------------|-------|
-| Target type identity (`TargetTemplate` / suffix) | `:target` + `:core` (F-021) | **Yes** | Parallel `TargetType` in core; templates kept for compat in F-021. Registry in F-022/F-023. |
-| Name + dep-type `Validator` | `:validation` | **Yes** | Keep framework; Android content rules as plugins |
-| Content validators (`onlyAllowResources`, …) | `:android` + `:validation` helpers | **Split** | Generic dir checks → core; Android paths → android plugin |
+| Target type identity (`TargetTemplate` / suffix) | `:target` + `:core` (F-021) | **Yes** | Parallel `TargetType` in core; templates kept for compat. Registry in F-023. |
+| Name + dep-type `Validator` | `:core` + `:validation` facade (F-022) | **Yes** | Core `TargetValidator` + factories; legacy API re-exports |
+| Content validators (`onlyAllowResources`, …) | core predicates + `:android` helpers (F-022) | **Split** | Pure `ContentRule` in core; Gradle listing + Android helpers in platform |
 | Dependency model + apply | `:deps` | **Mostly yes** | Strip AGP-ish config features; catalog generators may stay tooling |
 | Settings store | `:config` | **Split** | Generic `SettingsStore` / plugin registry → core; `AndroidProjectSettings` → android |
 | Owners | `:owners` | **Optional / yes** | Platform-agnostic metadata |
@@ -323,9 +324,9 @@ Suggested extraction order (tickets F-020…F-024):
 1. Document public API — **done (F-020):** [`forma-core-api.md`](forma-core-api.md)
    (types, restriction graph, validator SPI, target registry, coords preview,
    `library` suffix decision).
-2. Create `plugins/core` + TargetType + RestrictionGraph + wire Android matrix from DEPENDENCY-MATRIX (F-021). Parallel types + facades; full move later.
-3. Re-home `applyDependencies` project-validation path on core validators (F-022).
-4. Leave `:android` as the first platform package implementing templates + AGP features (F-023).
+2. Create `plugins/core` + TargetType + RestrictionGraph + wire Android matrix from DEPENDENCY-MATRIX — **done (F-021)**.
+3. Validation SPI + content predicates in core; `:validation` thin facade — **done (F-022)**.
+4. Wire Android DSL / registry as first consumer of core (F-023); sample stays green.
 5. Coordinates: e.g. `tools.forma:core` vs `tools.forma.android` (F-024).
 
 ---

docs/PROGRESS.md

@@ -2,6 +2,30 @@
 
 Newest entries first.
 
+## 2026-07-13 — F-022 Extract validation framework into forma-core
+
+- **Ticket:** F-022 → `done`
+- **Branch:** `forma/F-022-validation-framework` (from `origin/v2`)
+- **Skills/modes:** Grok Build `--mode full` (plan design → implement; implement hit max-turns); Hermes finished docs, OnlyLayout empty-list parity, builds, commit/PR
+- **Core (`tools.forma.core.validation`):**
+  - `TargetValidator` SPI + `AcceptAny`
+  - `dependencyTypeValidator` / `selfTypeValidator` with **identity cache** (F-017)
+  - `FormaValidationException` (recognizable suffix messages)
+  - Pure `ContentRule` + `NoResourcesUnderMain` / `OnlyResourcesUnderMain` / `OnlyLayoutResources`
+  - Unit tests: `TargetValidatorTest`, `ContentRuleTest`
+- **Facades:**
+  - `:validation` `Validator`/`validator(TargetTemplate…)` → core; still throws `ProjectValidationError`
+  - `FormaTarget` implements `TargetRef`; `:target`/`:deps` depend on `:core`
+  - Android `commonValidators.kt` lists dirs via Gradle, checks via core rules
+- **Docs:** ARCHITECTURE graph/table/extraction; forma-core-api status + checklist; README Progress; TICKETS
+- **Verify (OpenJDK 17 + env-mac.sh):**
+  - `plugins/`: `./gradlew :core:test` → **BUILD SUCCESSFUL**
+  - `plugins/`: `./gradlew build` → **BUILD SUCCESSFUL** (68 tasks)
+  - `application/`: `./gradlew :binary:assembleDebug` → **BUILD SUCCESSFUL** (578 tasks)
+- **Commits/PRs:** this run — push + PR base `v2`
+- **Blockers:** none (Grok implement max-turns; tree completed by Hermes verify/docs)
+- **Next step:** F-023 Wire Android as first consumer of forma-core (registry / DSL)
+
 ## 2026-07-13 — Local maven publishing for plugin testing
 
 - **Scope:** tooling for F-018 AGP/Gradle smoke tests + external consumers

docs/forma-core-api.md

@@ -1,12 +1,13 @@
 # forma-core public API design (F-020)
 
-Design-only ticket. This document is the contract for extraction tickets
-**F-021…F-024**. It is grounded in the live plugins under `plugins/`
-(`:target`, `:validation`, `:deps`, `:config`, `:owners`, `:android`) and in
-[`ARCHITECTURE.md`](ARCHITECTURE.md) §6 + [`VISION.md`](VISION.md).
+Design ticket contract for extraction **F-021…F-024**. Grounded in the live
+plugins under `plugins/` and in [`ARCHITECTURE.md`](ARCHITECTURE.md) §6 +
+[`VISION.md`](VISION.md).
 
-**Status:** accepted design for workers. Code moves land in later tickets;
-do **not** treat this file as already-implemented packages.
+**Status:** accepted design. **Implemented so far:** F-021 (types +
+restriction graph + Android kit), **F-022** (validation SPI + content
+predicates in `plugins/core`; `:validation` is a Gradle facade). Registry /
+DSL consumption remains **F-023**.
 
 ---
 
@@ -401,7 +402,7 @@ Bazel adapter (later): same registry + restriction graph; replace
 |--------|--------|
 | **F-020** (this doc) | Public API design only |
 | **F-021** | Create `plugins/core` (or move packages); target types + **restriction graph** + wire Android matrix data; keep binary/API facades so sample builds |
-| **F-022** | Move validation SPI, default suffix validators, content predicates; Android content helpers call core |
+| **F-022** | **Done:** validation SPI, identity-cached factories, content predicates in `plugins/core`; Android helpers call core; `:validation` facade |
 | **F-023** | Android DSL uses registry; delete duplicated allow-lists from individual `*.kt` entrypoints where safe; sample green |
 | **F-024** | Publishing coordinates, README/Portal metadata, deprecate old plugin jars if merged |
 
@@ -413,15 +414,15 @@ Do not skip to JVM targets (F-030) until F-023 is done.
 
 **Must ship in forma-core v1**
 
-- [ ] `TargetType`, `TargetRef`, `NameMatcher` / `SuffixNameMatcher`
-- [ ] `TargetRegistry` + `TargetRegistration` + `DefaultTargetRegistry`
-- [ ] `RestrictionGraph` / `RestrictionRule` / `EdgeKind`
-- [ ] `TargetValidator`, `AcceptAny`, `dependencyTypeValidator`, `selfTypeValidator`
-- [ ] Content rule interfaces + `NoResourcesUnderMain` / `OnlyResourcesUnderMain`
-- [ ] Validation error type + message helpers (suffix lists)
+- [x] `TargetType`, `TargetRef`, `NameMatcher` / `SuffixNameMatcher` (F-021)
+- [ ] `TargetRegistry` + `TargetRegistration` + `DefaultTargetRegistry` (F-023)
+- [x] `RestrictionGraph` / `RestrictionRule` / `EdgeKind` (F-021)
+- [x] `TargetValidator`, `AcceptAny`, `dependencyTypeValidator`, `selfTypeValidator` (F-022)
+- [x] Content rule interfaces + `NoResourcesUnderMain` / `OnlyResourcesUnderMain` / `OnlyLayoutResources` (F-022)
+- [x] Validation error type + message helpers (suffix lists) — core `FormaValidationException`; facade keeps `ProjectValidationError` (F-022)
 - [ ] `SettingsStore`, `PluginBindingStore` (from today’s config interfaces)
 - [ ] Dependency model types needed for project-edge validation
-- [ ] Identity-cached validator factory (F-017 behavior)
+- [x] Identity-cached validator factory (F-017 behavior) (F-022)
 
 **Explicitly deferred**
 

plugins/android/src/main/java/tools/forma/android/validation/commonValidators.kt

@@ -2,29 +2,63 @@ package tools.forma.android.validation
 
 import org.gradle.api.Project
 import java.io.File
-import tools.forma.validation.validateDirectoryContent
+import tools.forma.core.validation.NoResourcesUnderMain
+import tools.forma.core.validation.OnlyLayoutResources
+import tools.forma.core.validation.OnlyResourcesUnderMain
+import tools.forma.validation.buildException
+// validateDirectoryContent kept in :validation as Gradle-coupled facade (core ContentRule is pure)
 
-fun Project.disallowResources() = validateDirectoryContent(
-    dir = "./src/main",
-    errorMsg = "Please make sure this does not contain `res` directory"
-) { files ->
-    files.filter(File::isDirectory)
-        .map { it.name }
-        .run { !contains("res") }
+/**
+ * Gradle-coupled content helpers. Pure predicates live in core (F-022); listing + error wrapping
+ * uses the validation facade so behavior and messages for existing DSLs are unchanged.
+ */
+
+fun Project.disallowResources() {
+    val dir = "./src/main"
+    val files = file(dir).listFiles() ?: throw buildException(project.name, "'$dir' does not exists")
+    val names = files.filter(File::isDirectory).map { it.name }
+    val failure = NoResourcesUnderMain.check(names)
+    if (failure != null) {
+        throw buildException(
+            project.name,
+            """$failure
+                  |Current list of files in $dir:
+                  |${files.joinToString("\n") { it.name }}
+                """.trimMargin()
+        )
+    }
 }
 
-fun Project.onlyAllowResources() = validateDirectoryContent(
-    dir = "./src/main",
-    errorMsg = "Please make sure this target only contains `res` folder in `src/main`"
-) {
-    it.filter(File::isDirectory)
-        .run { size == 1 && first().name == "res" }
+fun Project.onlyAllowResources() {
+    val dir = "./src/main"
+    val files = file(dir).listFiles() ?: throw buildException(project.name, "'$dir' does not exists")
+    val names = files.filter(File::isDirectory).map { it.name }
+    val failure = OnlyResourcesUnderMain.check(names)
+    if (failure != null) {
+        throw buildException(
+            project.name,
+            """$failure
+                  |Current list of files in $dir:
+                  |${files.joinToString("\n") { it.name }}
+                """.trimMargin()
+        )
+    }
 }
 
-fun Project.onlyAllowLayouts() = validateDirectoryContent(
-    dir = "./src/main/res",
-    errorMsg = "Please make sure this target only contains `layout.*` folders in `src/main/res`"
-) {
-    it.filter(File::isDirectory)
-        .all { it.name.startsWith("layout") }
+fun Project.onlyAllowLayouts() {
+    val dir = "./src/main/res"
+    val files = file(dir).listFiles() ?: throw buildException(project.name, "'$dir' does not exists")
+    val names = files.filter(File::isDirectory).map { it.name }
+    val failure = OnlyLayoutResources.check(names)
+    if (failure != null) {
+        throw buildException(
+            project.name,
+            """$failure
+                  |Current list of files in $dir:
+                  |${files.joinToString("\n") { it.name }}
+                """.trimMargin()
+        )
+    }
 }
+
+// Note: validateDirectoryContent remains in tools.forma.validation for any external Gradle-coupled usage.

plugins/core/src/main/java/tools/forma/core/validation/ContentRule.kt

@@ -0,0 +1,47 @@
+package tools.forma.core.validation
+
+/**
+ * Pure predicate for directory content validation (no Gradle APIs).
+ * Implementations receive relative file/dir names under the inspected root (e.g. "src/main" or "src/main/res").
+ * @return null if content is acceptable, otherwise a human-readable failure reason.
+ */
+fun interface ContentRule {
+    fun check(filesUnderRoot: List<String>): String?
+}
+
+/** Rejects any "res" directory under the inspected root (e.g. src/main). */
+object NoResourcesUnderMain : ContentRule {
+    override fun check(filesUnderRoot: List<String>): String? =
+        if (filesUnderRoot.any { it == "res" }) {
+            "Please make sure this does not contain `res` directory"
+        } else {
+            null
+        }
+}
+
+/** Requires the inspected root to contain exactly one "res" directory and nothing else. */
+object OnlyResourcesUnderMain : ContentRule {
+    override fun check(filesUnderRoot: List<String>): String? {
+        val dirs = filesUnderRoot
+        return if (dirs.size == 1 && dirs.first() == "res") {
+            null
+        } else {
+            "Please make sure this target only contains `res` folder in `src/main`"
+        }
+    }
+}
+
+/**
+ * For res/ inspection: every top-level entry under res must start with "layout".
+ * Empty list is OK (matches historical `list.all { startsWith("layout") }` on empty).
+ */
+object OnlyLayoutResources : ContentRule {
+    override fun check(filesUnderRoot: List<String>): String? {
+        val allLayouts = filesUnderRoot.all { it.startsWith("layout") }
+        return if (allLayouts) {
+            null
+        } else {
+            "Please make sure this target only contains `layout.*` folders in `src/main/res`"
+        }
+    }
+}