return partial config from LoadConfig with errors

LoadConfig should return any parsed configuration in order for the
caller to verify `required_version`.

internal/command/init.go

@@ -227,7 +227,7 @@ func (c *InitCommand) Run(args []string) int {
 	var back backend.Backend
 	if flagBackend {
 
-		be, backendOutput, backendDiags := c.initBackend(config.Root.Module, flagConfigExtra)
+		be, backendOutput, backendDiags := c.initBackend(config.Module, flagConfigExtra)
 		diags = diags.Append(backendDiags)
 		if backendDiags.HasErrors() {
 			c.showDiagnostics(diags)

internal/configs/configload/loader_load.go

@@ -21,7 +21,13 @@ import (
 func (l *Loader) LoadConfig(rootDir string) (*configs.Config, hcl.Diagnostics) {
 	rootMod, diags := l.parser.LoadConfigDir(rootDir)
 	if rootMod == nil || diags.HasErrors() {
-		return nil, diags
+		// Ensure we return any parsed modules here so that required_version
+		// constraints can be verified even when encountering errors.
+		cfg := &configs.Config{
+			Module: rootMod,
+		}
+
+		return cfg, diags
 	}
 
 	cfg, cDiags := configs.BuildConfig(rootMod, configs.ModuleWalkerFunc(l.moduleWalkerLoad))

internal/configs/configload/loader_load_test.go

@@ -91,8 +91,16 @@ func TestLoaderLoadConfig_loadDiags(t *testing.T) {
 		t.Fatalf("unexpected error from NewLoader: %s", err)
 	}
 
-	_, diags := loader.LoadConfig(fixtureDir)
+	cfg, diags := loader.LoadConfig(fixtureDir)
 	if !diags.HasErrors() {
-		t.Fatalf("success; want error")
+		t.Fatal("success; want error")
+	}
+
+	if cfg == nil {
+		t.Fatal("partial config not returned with diagnostics")
+	}
+
+	if cfg.Module == nil {
+		t.Fatal("expected config module")
 	}
 }