From 53134b60faf2601d8d9d225b2141445f6a3e7789 Mon Sep 17 00:00:00 2001
From: Marcin Tojek <marcin@coder.com>
Date: Mon, 17 Jul 2023 13:45:50 +0200
Subject: [PATCH] feat: assume empty value for ephemeral, required parameter
 while stopping workspace

---
 coderd/wsbuilder/wsbuilder.go   |  4 +++-
 codersdk/richparameters.go      |  9 ++++++++-
 codersdk/richparameters_test.go | 21 ++++++++++++++++++++-
 3 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/coderd/wsbuilder/wsbuilder.go b/coderd/wsbuilder/wsbuilder.go
index 7f6d840f9db6d..2b29c06c4c6bf 100644
--- a/coderd/wsbuilder/wsbuilder.go
+++ b/coderd/wsbuilder/wsbuilder.go
@@ -495,8 +495,10 @@ func (b *Builder) getParameters() (names, values []string, err error) {
 	if err != nil {
 		return nil, nil, BuildError{http.StatusBadRequest, "Unable to build workspace with unsupported parameters", err}
 	}
+
 	resolver := codersdk.ParameterResolver{
-		Rich: db2sdk.WorkspaceBuildParameters(lastBuildParameters),
+		Rich:       db2sdk.WorkspaceBuildParameters(lastBuildParameters),
+		Transition: codersdk.WorkspaceTransition(b.trans),
 	}
 	for _, templateVersionParameter := range templateVersionParameters {
 		tvp, err := db2sdk.TemplateVersionParameter(templateVersionParameter)
diff --git a/codersdk/richparameters.go b/codersdk/richparameters.go
index d26b6abeed0c6..22b81e89caa21 100644
--- a/codersdk/richparameters.go
+++ b/codersdk/richparameters.go
@@ -145,12 +145,18 @@ func validationEnabled(param TemplateVersionParameter) bool {
 // correctly validates.
 // @typescript-ignore ParameterResolver
 type ParameterResolver struct {
-	Rich []WorkspaceBuildParameter
+	Rich       []WorkspaceBuildParameter
+	Transition WorkspaceTransition
 }
 
 // ValidateResolve checks the provided value, v, against the parameter, p, and the previous build.  If v is nil, it also
 // resolves the correct value.  It returns the value of the parameter, if valid, and an error if invalid.
 func (r *ParameterResolver) ValidateResolve(p TemplateVersionParameter, v *WorkspaceBuildParameter) (value string, err error) {
+	// Assume value for required, ephemeral parameter for stopped/deleted workspace
+	if p.Ephemeral && r.Transition != "" && r.Transition != WorkspaceTransitionStart {
+		return "", nil
+	}
+
 	prevV := r.findLastValue(p)
 	if !p.Mutable && v != nil && prevV != nil {
 		return "", xerrors.Errorf("Parameter %q is not mutable, so it can't be updated after creating a workspace.", p.Name)
@@ -171,6 +177,7 @@ func (r *ParameterResolver) ValidateResolve(p TemplateVersionParameter, v *Works
 			Value: p.DefaultValue,
 		}
 	}
+
 	err = ValidateWorkspaceBuildParameter(p, resolvedValue, prevV)
 	if err != nil {
 		return "", err
diff --git a/codersdk/richparameters_test.go b/codersdk/richparameters_test.go
index e009421d9a553..75d95d886aeb1 100644
--- a/codersdk/richparameters_test.go
+++ b/codersdk/richparameters_test.go
@@ -379,7 +379,9 @@ func TestParameterResolver_ValidateResolve_Ephemeral_UseEmptyDefault(t *testing.
 
 func TestParameterResolver_ValidateResolve_Ephemeral_RequiredButMissing(t *testing.T) {
 	t.Parallel()
-	uut := codersdk.ParameterResolver{}
+	uut := codersdk.ParameterResolver{
+		Transition: codersdk.WorkspaceTransitionStart,
+	}
 	p := codersdk.TemplateVersionParameter{
 		Name:      "n",
 		Type:      "number",
@@ -394,3 +396,20 @@ func TestParameterResolver_ValidateResolve_Ephemeral_RequiredButMissing(t *testi
 	require.Error(t, err) // Parameter is required, but not provided.
 	require.Equal(t, "", v)
 }
+
+func TestParameterResolver_ValidateResolve_Ephemeral_RequiredButMissing_StoppedWorkspace(t *testing.T) {
+	t.Parallel()
+	uut := codersdk.ParameterResolver{
+		Transition: codersdk.WorkspaceTransitionStop,
+	}
+	p := codersdk.TemplateVersionParameter{
+		Name:      "n",
+		Type:      "number",
+		Mutable:   true,
+		Required:  true,
+		Ephemeral: true,
+	}
+	v, err := uut.ValidateResolve(p, nil)
+	require.NoError(t, err) // Parameter is not provided, but resolver assumes an empty value.
+	require.Equal(t, "", v)
+}