Implement hcl parse diagnostics

internal/context/context.go

@@ -7,6 +7,7 @@ import (
 	"github.com/hashicorp/terraform-ls/internal/filesystem"
 	"github.com/hashicorp/terraform-ls/internal/terraform/rootmodule"
 	"github.com/hashicorp/terraform-ls/internal/watcher"
+	"github.com/hashicorp/terraform-ls/langserver/diagnostics"
 	"github.com/sourcegraph/go-lsp"
 )
 
@@ -33,6 +34,7 @@ var (
 	ctxRootModuleWalker  = &contextKey{"root module walker"}
 	ctxRootModuleLoader  = &contextKey{"root module loader"}
 	ctxRootDir           = &contextKey{"root directory"}
+	ctxDiags             = &contextKey{"diagnostics"}
 )
 
 func missingContextErr(ctxKey *contextKey) *MissingContextErr {
@@ -211,3 +213,16 @@ func RootModuleLoader(ctx context.Context) (rootmodule.RootModuleLoader, error)
 	}
 	return w, nil
 }
+
+func WithDiagnostics(ctx context.Context, diags *diagnostics.Notifier) context.Context {
+	return context.WithValue(ctx, ctxDiags, diags)
+}
+
+func Diagnostics(ctx context.Context) (*diagnostics.Notifier, error) {
+	diags, ok := ctx.Value(ctxDiags).(*diagnostics.Notifier)
+	if !ok {
+		return nil, missingContextErr(ctxDiags)
+	}
+
+	return diags, nil
+}

langserver/diagnostics/diagnostics.go

@@ -0,0 +1,91 @@
+package diagnostics
+
+import (
+	"context"
+	"sync"
+
+	"github.com/creachadair/jrpc2"
+	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/hcl/v2/hclparse"
+	ilsp "github.com/hashicorp/terraform-ls/internal/lsp"
+	"github.com/sourcegraph/go-lsp"
+)
+
+type documentContext struct {
+	ctx  context.Context
+	uri  lsp.DocumentURI
+	text []byte
+}
+
+type Notifier struct {
+	sessCtx          context.Context
+	hclDocs          chan<- documentContext
+	closeHclDocsOnce sync.Once
+}
+
+func NewNotifier(sessCtx context.Context) *Notifier {
+	hclDocs := make(chan documentContext, 10)
+	go hclDiags(hclDocs)
+	return &Notifier{hclDocs: hclDocs, sessCtx: sessCtx}
+}
+
+func (n *Notifier) DiagnoseHCL(ctx context.Context, uri lsp.DocumentURI, text []byte) {
+	select {
+	case <-n.sessCtx.Done():
+		n.closeHclDocsOnce.Do(func() {
+			close(n.hclDocs)
+		})
+		return
+	case n.hclDocs <- documentContext{ctx: ctx, uri: uri, text: text}:
+	}
+}
+
+func hclDiags(docs <-chan documentContext) {
+	for d := range docs {
+		diags := []lsp.Diagnostic{}
+
+		_, hclDiags := hclparse.NewParser().ParseHCL(d.text, string(d.uri))
+		for _, hclDiag := range hclDiags {
+			if hclDiag.Subject != nil {
+				diags = append(diags, lsp.Diagnostic{
+					Range:    ilsp.HCLRangeToLSP(*hclDiag.Subject),
+					Severity: hclSeverityToLSP(hclDiag.Severity),
+					Source:   "HCL",
+					Message:  lspMessage(hclDiag),
+				})
+			}
+		}
+
+		if err := jrpc2.PushNotify(d.ctx, "textDocument/publishDiagnostics", lsp.PublishDiagnosticsParams{
+			URI:         d.uri,
+			Diagnostics: diags,
+		}); !acceptableError(err) {
+			panic(err)
+		}
+	}
+}
+
+func hclSeverityToLSP(severity hcl.DiagnosticSeverity) lsp.DiagnosticSeverity {
+	var sev lsp.DiagnosticSeverity
+	switch severity {
+	case hcl.DiagError:
+		sev = lsp.Error
+	case hcl.DiagWarning:
+		sev = lsp.Warning
+	case hcl.DiagInvalid:
+		panic("invalid diagnostic")
+	}
+	return sev
+}
+
+func lspMessage(diag *hcl.Diagnostic) string {
+	m := diag.Summary
+	if diag.Detail != "" {
+		m += ": " + diag.Detail
+	}
+	return m
+}
+
+func acceptableError(err error) bool {
+	return true
+}

langserver/handlers/did_change.go

@@ -49,6 +49,16 @@ func TextDocumentDidChange(ctx context.Context, params DidChangeTextDocumentPara
 		return err
 	}
 
+	diags, err := lsctx.Diagnostics(ctx)
+	if err != nil {
+		return err
+	}
+	text, err := f.Text()
+	if err != nil {
+		return err
+	}
+	diags.DiagnoseHCL(ctx, params.TextDocument.URI, text)
+
 	cf, err := lsctx.RootModuleCandidateFinder(ctx)
 	if err != nil {
 		return err

langserver/handlers/did_open.go

@@ -14,6 +14,13 @@ import (
 )
 
 func (lh *logHandler) TextDocumentDidOpen(ctx context.Context, params lsp.DidOpenTextDocumentParams) error {
+
+	diags, err := lsctx.Diagnostics(ctx)
+	if err != nil {
+		return err
+	}
+	diags.DiagnoseHCL(ctx, params.TextDocument.URI, []byte(params.TextDocument.Text))
+
 	fs, err := lsctx.DocumentStorage(ctx)
 	if err != nil {
 		return err

langserver/handlers/service.go

@@ -15,6 +15,7 @@ import (
 	"github.com/hashicorp/terraform-ls/internal/filesystem"
 	"github.com/hashicorp/terraform-ls/internal/terraform/rootmodule"
 	"github.com/hashicorp/terraform-ls/internal/watcher"
+	"github.com/hashicorp/terraform-ls/langserver/diagnostics"
 	"github.com/hashicorp/terraform-ls/langserver/session"
 	"github.com/sourcegraph/go-lsp"
 )
@@ -141,6 +142,7 @@ func (svc *service) Assigner() (jrpc2.Assigner, error) {
 	}
 
 	rmLoader := rootmodule.NewRootModuleLoader(svc.sessCtx, svc.modMgr)
+	diags := diagnostics.NewNotifier(svc.sessCtx)
 
 	rootDir := ""
 
@@ -173,6 +175,7 @@ func (svc *service) Assigner() (jrpc2.Assigner, error) {
 			if err != nil {
 				return nil, err
 			}
+			ctx = lsctx.WithDiagnostics(ctx, diags)
 			ctx = lsctx.WithDocumentStorage(ctx, fs)
 			ctx = lsctx.WithRootModuleCandidateFinder(ctx, svc.modMgr)
 			return handle(ctx, req, TextDocumentDidChange)
@@ -182,6 +185,7 @@ func (svc *service) Assigner() (jrpc2.Assigner, error) {
 			if err != nil {
 				return nil, err
 			}
+			ctx = lsctx.WithDiagnostics(ctx, diags)
 			ctx = lsctx.WithDocumentStorage(ctx, fs)
 			ctx = lsctx.WithRootDirectory(ctx, &rootDir)
 			ctx = lsctx.WithRootModuleCandidateFinder(ctx, svc.modMgr)