feat: migrate provider to generated schema (#1208)

- add code generation tooling (parser, templates, docs, tests) to mirror libvirtxml
- switch domain, network, pool, and volume resources plus examples/docs to the generated schemas/models/conversions
- add schema helpers, lint fixes, and improved snake_case utility

Author: dmacvicar

.github/workflows/test.yml

@@ -27,6 +27,8 @@ jobs:
       - uses: actions/setup-go@v5
         with:
           go-version: ${{ matrix.go-version }}
+      - name: Generate code
+        run: make generate
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v7
         with:

.gitignore

@@ -1,5 +1,6 @@
 # Binaries
 terraform-provider-libvirt
+/codegen
 *.exe
 *.dll
 *.so
@@ -35,3 +36,9 @@ override.tf.json
 # OS
 .DS_Store
 Thumbs.db
+
+# Generated code
+internal/generated/*.gen.go
+
+tmp
+tmp/

AGENTS.md

@@ -189,28 +189,23 @@ Example:
 
 **Key principle**: If libvirt XML has a container element (like `<devices>`), we must have a corresponding nested object in HCL.
 
-**Preserve User Intent Pattern**
+**Field Read Semantics**
 
-**Rule**: Only populate optional fields in state if the user explicitly specified them in their configuration.
+Terraform state reflects what the user cares about, not the entire API response.
 
-**Why**: Libvirt sets defaults for many optional fields. If we naively read all values back, Terraform detects drift between null (user didn't specify) and libvirt's default, causing unwanted plan diffs.
+**Computed** (not Optional) - Always read from API
+- Examples: `id`, `key`, `allocation`, `physical`
+- `model.Key = types.StringValue(xml.Key)`
 
-**Apply to**: Optional fields where libvirt provides defaults (on_poweroff, current_memory, boot_devices, autostart, unit, type, etc.)
+**Optional** (with or without Computed) - Only read if user specified
+- If user didn't specify, don't populate (libvirt defaults are irrelevant)
+- Examples: `on_poweroff`, `type`, `capacity` (when optional)
+- `if !plan.Field.IsNull() { model.Field = types.StringValue(xml.Field) }`
 
-**Don't apply to**: Required fields (name, memory) or purely computed fields (uuid, id)
+**Required** - Always read
+- User must specify, always in state
 
-Example:
-```go
-// ❌ WRONG
-if domain.OnPoweroff != "" {
-    model.OnPoweroff = types.StringValue(domain.OnPoweroff)
-}
-
-// ✅ CORRECT
-if !model.OnPoweroff.IsNull() && !model.OnPoweroff.IsUnknown() && domain.OnPoweroff != "" {
-    model.OnPoweroff = types.StringValue(domain.OnPoweroff)
-}
-```
+Key insight: The `Optional` flag means "only populate if user cares", regardless of whether it's also Computed.
 
 ## Project Structure
 

Makefile

@@ -1,4 +1,4 @@
-.PHONY: help build install test testacc testacc-tofu sweep lint fmt clean
+.PHONY: help build install test testacc testacc-tofu sweep lint fmt clean generate
 
 # Default target
 .DEFAULT_GOAL := help
@@ -13,7 +13,11 @@ help: ## Display this help message
 	@echo "Terraform Provider Libvirt - Available targets:"
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2}'
 
-build: ## Build the provider binary
+generate: ## Run code generation
+	@echo "Running code generator..."
+	@go run ./internal/codegen
+
+build: generate ## Build the provider binary
 	@echo "Building terraform-provider-libvirt..."
 	@go build $(LDFLAGS) -o terraform-provider-libvirt
 
@@ -23,11 +27,11 @@ install: build ## Install the provider to local Terraform plugin directory
 	@cp terraform-provider-libvirt ~/.terraform.d/plugins/registry.terraform.io/dmacvicar/libvirt/$(VERSION)/linux_amd64/
 	@echo "Installed to ~/.terraform.d/plugins/registry.terraform.io/dmacvicar/libvirt/$(VERSION)/linux_amd64/"
 
-test: ## Run unit tests
+test: generate ## Run unit tests
 	@echo "Running unit tests..."
 	@go test ./... -v
 
-testacc: ## Run acceptance tests (requires running libvirt)
+testacc: generate ## Run acceptance tests (requires running libvirt)
 	@echo "Running acceptance tests..."
 	@TF_ACC=1 go test -count=1 -v -timeout 10m ./internal/provider
 
@@ -38,7 +42,7 @@ sweep: ## Clean up leaked test resources from failed tests
 	@echo "Running test sweepers..."
 	@cd internal/provider && go test -sweep=$(shell if [ -n "$$LIBVIRT_TEST_URI" ]; then echo "$$LIBVIRT_TEST_URI"; else echo "qemu:///system"; fi) -timeout 10m .
 
-lint: ## Run golangci-lint
+lint: generate ## Run golangci-lint
 	@echo "Verifying golangci-lint config..."
 	@golangci-lint config verify
 	@echo "Running golangci-lint..."