fix: use pointer handle null values (#679)

Note: Required after the update to `hashicorp/packer-plugin-sdk` v0.6.6.

Change `DirPerm` in `OutputConfig` from `os.FileMode` to `*os.FileMode`
so that HCL2 can correctly represent the field as optional/nullable.

When `directory_permission` is not set in a onfiguration, the packer-sdc generated flat struct receives a cty null value for the field. Assigning a cty null to a non-pointer `os.FileMode` causes a runtime panic: "null value is not allowed". Using a pointer type allows the field to be nil when omitted, which is handled in `Prepare()` by falling back to the default permission of `0750`.

The corresponding generated `hcl2spec.go` files (`output_config` and `step_export`) are updated to mirror the pointer type. Because the pointer is now declared in the source struct, future runs of `make generate` will regenerate these files with `*os.FileMode`.

Fixes:
- Runtime error: null value is not allowed [directory_permission]
- Build error: cannot use DirPerm (type *os.FileMode) as os.FileMode

Ref: #675

Signed-off-by: Ryan Johnson <ryan.johnson@broadcom.com>

Author: tenthirtyam

.web-docs/components/builder/vsphere-clone/README.md

@@ -1641,7 +1641,7 @@ The above configuration would create the following files:
   created, must be empty prior to running the builder. By default, this is
   "output-<buildName>" where "buildName" is the name of the build.
 
-- `directory_permission` (os.FileMode) - The permissions to apply to the "output_directory", and to any parent
+- `directory_permission` (\*os.FileMode) - The permissions to apply to the "output_directory", and to any parent
   directories that get created for output_directory.  By default, this is
   "0750". You should express the permission as quoted string with a
   leading zero such as "0755" in JSON file, because JSON does not support

.web-docs/components/builder/vsphere-iso/README.md

@@ -1489,7 +1489,7 @@ The above configuration would create the following files:
   created, must be empty prior to running the builder. By default, this is
   "output-<buildName>" where "buildName" is the name of the build.
 
-- `directory_permission` (os.FileMode) - The permissions to apply to the "output_directory", and to any parent
+- `directory_permission` (\*os.FileMode) - The permissions to apply to the "output_directory", and to any parent
   directories that get created for output_directory.  By default, this is
   "0750". You should express the permission as quoted string with a
   leading zero such as "0755" in JSON file, because JSON does not support

Makefile

@@ -29,6 +29,11 @@ testacc: dev
 
 generate: install-packer-sdc
 	@go generate ./...
+	# Patch the generated files to use *os.FileMode so null values are handled correctly.
+	@for f in builder/vsphere/common/output_config.hcl2spec.go builder/vsphere/common/step_export.hcl2spec.go; do \
+		awk '/DirPerm/{gsub(/ os\.FileMode/, " *os.FileMode")} {print}' "$$f" > "$$f.tmp" && mv "$$f.tmp" "$$f"; \
+	done
+	@go fmt ./...
 	@rm -rf .docs
 	@packer-sdc renderdocs -src "docs" -partials docs-partials/ -dst ".docs/"
 	@./.web-docs/scripts/compile-to-webdocs.sh "." ".docs" ".web-docs" "hashicorp"

builder/vsphere/common/output_config.go

@@ -31,16 +31,17 @@ type OutputConfig struct {
 	// leading zero such as "0755" in JSON file, because JSON does not support
 	// octal value. In Unix-like OS, the actual permission may differ from
 	// this value because of umask.
-	DirPerm os.FileMode `mapstructure:"directory_permission" required:"false"`
+	DirPerm *os.FileMode `mapstructure:"directory_permission" required:"false"`
 }
 
 func (c *OutputConfig) Prepare(ctx *interpolate.Context, pc *common.PackerConfig) []error {
 	if c.OutputDir == "" {
 		c.OutputDir = fmt.Sprintf("output-%s", pc.PackerBuildName)
 	}
 
-	if runtime.GOOS != "windows" && c.DirPerm == 0 {
-		c.DirPerm = 0750
+	if runtime.GOOS != "windows" && (c.DirPerm == nil || *c.DirPerm == 0) {
+		perm := os.FileMode(0750)
+		c.DirPerm = &perm
 	}
 
 	return nil

builder/vsphere/common/output_config.hcl2spec.go

@@ -159,7 +159,7 @@ func (c *ExportConfig) Prepare(ctx *interpolate.Context, lc *LocationConfig, pc
 	}
 
 	// Check if the output directory exists.
-	if err := os.MkdirAll(c.OutputDir.OutputDir, c.OutputDir.DirPerm); err != nil {
+	if err := os.MkdirAll(c.OutputDir.OutputDir, *c.OutputDir.DirPerm); err != nil {
 		errs = packersdk.MultiErrorAppend(errs, errors.Wrap(err, "unable to make directory for export"))
 	}
 

builder/vsphere/common/step_export.go

@@ -7,7 +7,7 @@
   created, must be empty prior to running the builder. By default, this is
   "output-<buildName>" where "buildName" is the name of the build.
 
-- `directory_permission` (os.FileMode) - The permissions to apply to the "output_directory", and to any parent
+- `directory_permission` (\*os.FileMode) - The permissions to apply to the "output_directory", and to any parent
   directories that get created for output_directory.  By default, this is
   "0750". You should express the permission as quoted string with a
   leading zero such as "0755" in JSON file, because JSON does not support