ci: add validate command

d2cli/help.go

@@ -23,6 +23,7 @@ Usage:
   %[1]s layout [name]
   %[1]s fmt file.d2 ...
   %[1]s play [--theme=0] [--sketch] file.d2
+  %[1]s validate file.d2 ...
 
 %[1]s compiles and renders file.d2 to file.svg | file.png
 It defaults to file.svg if an output path is not provided.
@@ -40,6 +41,7 @@ Subcommands:
   %[1]s themes - Lists available themes
   %[1]s fmt file.d2 ... - Format passed files
 	%[1]s play file.d2 - Opens the file in playground, an online web viewer (https://play.d2lang.com)
+  %[1]s validate file.d2 ... - Validate input files
 
 See more docs and the source code at https://oss.terrastruct.com/d2.
 Hosted icons at https://icons.terrastruct.com.

d2cli/main.go

@@ -173,6 +173,8 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 			return fmtCmd(ctx, ms, *checkFlag)
 		case "play":
 			return playCmd(ctx, ms)
+		case "validate":
+			return validateCmd(ctx, ms)
 		case "version":
 			if len(ms.Opts.Flags.Args()) > 1 {
 				return xmain.UsageErrorf("version subcommand accepts no arguments")

d2cli/validate.go

@@ -0,0 +1,35 @@
+package d2cli
+
+import (
+	"context"
+
+	"oss.terrastruct.com/d2/d2lib"
+	"oss.terrastruct.com/util-go/xdefer"
+	"oss.terrastruct.com/util-go/xmain"
+)
+
+func validateCmd(ctx context.Context, ms *xmain.State) (err error) {
+	defer xdefer.Errorf(&err, "failed to validate")
+
+	ms.Opts = xmain.NewOpts(ms.Env, ms.Opts.Flags.Args()[1:])
+	if len(ms.Opts.Args) == 0 {
+		return xmain.UsageErrorf("validate must be passed at least one file to be validated")
+	}
+
+	for _, inputPath := range ms.Opts.Args {
+		if inputPath != "-" {
+			inputPath = ms.AbsPath(inputPath)
+		}
+
+		input, err := ms.ReadPath(inputPath)
+		if err != nil {
+			return err
+		}
+
+		_, err = d2lib.Parse(ctx, string(input), nil)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}