Merge pull request #4112 from hashicorp/maint/core-config/fixup-panic-on-missing-use

internal/config: Fix panic if no scoped use stanza found

Author: briancain

.changelog/4112.txt

@@ -0,0 +1,4 @@
+```release-note:bug
+core: Fix panic if no Use stanza found for given workspace scope on a build,
+deploy, release, or registry stanza.
+```

internal/config/app.go

@@ -278,6 +278,8 @@ func (c *App) Release(ctx *hcl.EvalContext) (*Release, error) {
 func (c *App) BuildUse(ctx *hcl.EvalContext) (string, error) {
 	if c.BuildRaw == nil {
 		return "", nil
+	} else if c.BuildRaw.Use == nil {
+		return "", nil
 	}
 
 	useType := c.BuildRaw.Use.Type
@@ -296,6 +298,8 @@ func (c *App) BuildUse(ctx *hcl.EvalContext) (string, error) {
 func (c *App) RegistryUse(ctx *hcl.EvalContext) (string, error) {
 	if c.BuildRaw == nil || c.BuildRaw.Registry == nil {
 		return "", nil
+	} else if c.BuildRaw.Registry.Use == nil {
+		return "", nil
 	}
 
 	useType := c.BuildRaw.Registry.Use.Type
@@ -314,6 +318,8 @@ func (c *App) RegistryUse(ctx *hcl.EvalContext) (string, error) {
 func (c *App) DeployUse(ctx *hcl.EvalContext) (string, error) {
 	if c.DeployRaw == nil {
 		return "", nil
+	} else if c.DeployRaw.Use == nil {
+		return "", nil
 	}
 
 	useType := c.DeployRaw.Use.Type
@@ -332,6 +338,8 @@ func (c *App) DeployUse(ctx *hcl.EvalContext) (string, error) {
 func (c *App) ReleaseUse(ctx *hcl.EvalContext) (string, error) {
 	if c.ReleaseRaw == nil {
 		return "", nil
+	} else if c.ReleaseRaw.Use == nil {
+		return "", nil
 	}
 
 	useType := c.ReleaseRaw.Use.Type