feat: parse .terraform-version files for stacks dirs

internal/features/stacks/decoder/stacks_context.go

@@ -33,6 +33,7 @@ func (pr *PathReader) PathContext(path lang.Path) (*decoder.PathContext, error)
 	}
 
 	// get terrafom version from statereader and use that to get the schema
+	// -> record.TerraformVersion is available now (if already set hehe)
 
 	// TODO: This only provides tfstacks schema. There is also tfdeploy schema
 	// TODO: this should only work for terraform 1.8 and above
@@ -68,7 +69,7 @@ func (pr *PathReader) PathContext(path lang.Path) (*decoder.PathContext, error)
 	for name, f := range record.ParsedStackFiles {
 		pathCtx.Files[name.String()] = f
 	}
-	
+
 	for name, f := range record.ParsedDeployFiles {
 		pathCtx.Files[name.String()] = f
 	}

internal/features/stacks/events.go

@@ -193,6 +193,20 @@ func (f *StacksFeature) decodeStacks(ctx context.Context, dir document.DirHandle
 	}
 	ids = append(ids, parseId)
 
+	tfVersion, err := f.stateStore.JobStore.EnqueueJob(ctx, job.Job{
+		Dir: dir,
+		Func: func(ctx context.Context) error {
+			return jobs.LoadTerraformVersion(ctx, f.fs, f.Store, path)
+		},
+		Type:        operation.OpTypeLoadModuleMetadata.String(),
+		DependsOn:   job.IDs{parseId},
+		IgnoreState: ignoreState,
+	})
+	if err != nil {
+		return ids, err
+	}
+	ids = append(ids, tfVersion)
+
 	// TODO: Implement the following functions where appropriate to stacks
 	// Future: LoadModuleMetadata(ctx, f.Store, path)
 	// Future: decodeDeclaredModuleCalls(ctx, dir, ignoreState)

internal/features/stacks/jobs/version.go

@@ -0,0 +1,50 @@
+package jobs
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+
+	"github.com/hashicorp/go-version"
+	"github.com/hashicorp/terraform-ls/internal/document"
+	"github.com/hashicorp/terraform-ls/internal/features/stacks/state"
+	"github.com/hashicorp/terraform-ls/internal/job"
+	"github.com/hashicorp/terraform-ls/internal/terraform/module/operation"
+)
+
+// TODO: find a place to register a watcher for this .terraform-version file (put this in a follow-up issue), for now reloading the window is okay enough
+// https://github.com/hashicorp/terraform-ls/blob/c47b2e51a0ca08628a596eca8d5cd11d005b7d87/internal/langserver/handlers/initialized.go#L25
+
+// LoadTerraformVersion loads the terraform version from the .terraform-version
+// file in the stack directory.
+func LoadTerraformVersion(ctx context.Context, fs ReadOnlyFS, stackStore *state.StackStore, stackPath string) error {
+	stackRecord, err := stackStore.StackRecordByPath(stackPath)
+	if err != nil {
+		return err
+	}
+
+	// Avoid parsing if it is already in progress or already known
+	if stackRecord.TerraformVersionState != operation.OpStateUnknown && !job.IgnoreState(ctx) {
+		return job.StateNotChangedErr{Dir: document.DirHandleFromPath(stackPath)}
+	}
+
+	stackStore.SetTerraformVersionState(stackPath, operation.OpStateLoading)
+
+	// read version file
+	v, err := fs.ReadFile(filepath.Join(stackPath, ".terraform-version"))
+	if err != nil {
+		stackStore.SetTerraformVersionError(stackPath, err)
+		return err
+	}
+
+	// parse version
+	version, err := version.NewVersion(strings.TrimSpace(string(v)))
+	if err != nil {
+		stackStore.SetTerraformVersionError(stackPath, err)
+		return err
+	}
+
+	stackStore.SetTerraformVersion(stackPath, version)
+
+	return nil
+}

internal/features/stacks/state/stacks_record.go

@@ -4,6 +4,7 @@
 package state
 
 import (
+	"github.com/hashicorp/go-version"
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/terraform-ls/internal/features/stacks/ast"
 	globalAst "github.com/hashicorp/terraform-ls/internal/terraform/ast"
@@ -28,6 +29,10 @@ type StackRecord struct {
 	DeployParsingErr       error
 	DeployDiagnostics      ast.SourceDeployDiags
 	DeployDiagnosticsState globalAst.DiagnosticSourceState
+
+	TerraformVersion      *version.Version
+	TerraformVersionErr   error
+	TerraformVersionState operation.OpState
 }
 
 func (m *StackRecord) Path() string {

internal/features/stacks/state/stacks_store.go

@@ -7,6 +7,7 @@ import (
 	"log"
 
 	"github.com/hashicorp/go-memdb"
+	"github.com/hashicorp/go-version"
 	"github.com/hashicorp/terraform-ls/internal/features/stacks/ast"
 	globalState "github.com/hashicorp/terraform-ls/internal/state"
 	globalAst "github.com/hashicorp/terraform-ls/internal/terraform/ast"
@@ -17,6 +18,11 @@ type StackStore struct {
 	db        *memdb.MemDB
 	tableName string
 	logger    *log.Logger
+
+	// MaxStackNesting represents how many nesting levels we'd attempt
+	// to parse provider requirements before returning error.
+	MaxStackNesting int
+	changeStore     *globalState.ChangeStore
 }
 
 func (s *StackStore) SetLogger(logger *log.Logger) {
@@ -273,6 +279,61 @@ func (s *StackStore) UpdateDeployDiagnostics(path string, source globalAst.Diagn
 	return nil
 }
 
+func (s *StackStore) setTerraformVersionWithChangeNotification(path string, version *version.Version, vErr error, state operation.OpState) error {
+	txn := s.db.Txn(true)
+	defer txn.Abort()
+
+	oldStack, err := stackByPath(txn, path)
+	if err != nil {
+		return err
+	}
+	stack := oldStack.Copy()
+
+	stack.TerraformVersion = version
+	stack.TerraformVersionErr = vErr
+	stack.TerraformVersionState = state
+
+	err = txn.Insert(s.tableName, stack)
+	if err != nil {
+		return err
+	}
+
+	// err = s.queueStacksChange(oldStack, stack)
+	// if err != nil {
+	// 	return err
+	// }
+
+	txn.Commit()
+	return nil
+}
+
+func (s *StackStore) SetTerraformVersion(path string, version *version.Version) error {
+	return s.setTerraformVersionWithChangeNotification(path, version, nil, operation.OpStateLoaded)
+}
+
+func (s *StackStore) SetTerraformVersionError(path string, vErr error) error {
+	return s.setTerraformVersionWithChangeNotification(path, nil, vErr, operation.OpStateLoaded)
+}
+
+func (s *StackStore) SetTerraformVersionState(path string, state operation.OpState) error {
+	txn := s.db.Txn(true)
+	defer txn.Abort()
+
+	stack, err := stackCopyByPath(txn, path)
+	if err != nil {
+		return err
+	}
+
+	stack.TerraformVersionState = state
+	err = txn.Insert(s.tableName, stack)
+	if err != nil {
+		return err
+	}
+
+	txn.Commit()
+	return nil
+}
+
 func (s *StackStore) add(txn *memdb.Txn, stackPath string) error {
 	// TODO: Introduce Exists method to Txn?
 	obj, err := txn.First(s.tableName, "id", stackPath)

internal/terraform/module/operation/operation.go

@@ -38,4 +38,5 @@ const (
 	OpTypeParseStacks
 	OpTypeParseStacksConfiguration
 	OpTypeParseDeployConfiguration
+	OpTypeLoadTerraformVersion
 )