postcss: Make the resource cache key more stable

By using the input map as the basis, which means the hash will not change if we add/rename/remove options.

This happened in Hugo 0.99, as we added a new options. This is unortunate.

Unfortunately this means that the cache keys for PostCSS will change one more time in 0.100, but will be stable going forward.

Note that we have implemented this pattern in all the other resource transformers.

Updates #9787

resources/resource_transformers/postcss/postcss.go

@@ -60,7 +60,7 @@ func New(rs *resources.Spec) *Client {
 	return &Client{rs: rs}
 }
 
-func DecodeOptions(m map[string]any) (opts Options, err error) {
+func decodeOptions(m map[string]any) (opts Options, err error) {
 	if m == nil {
 		return
 	}
@@ -82,8 +82,8 @@ type Client struct {
 }
 
 // Process transforms the given Resource with the PostCSS processor.
-func (c *Client) Process(res resources.ResourceTransformer, options Options) (resource.Resource, error) {
-	return res.Transform(&postcssTransformation{rs: c.rs, options: options})
+func (c *Client) Process(res resources.ResourceTransformer, options map[string]any) (resource.Resource, error) {
+	return res.Transform(&postcssTransformation{rs: c.rs, optionsm: options})
 }
 
 // Some of the options from https://github.com/postcss/postcss-cli
@@ -137,12 +137,12 @@ func (opts Options) toArgs() []string {
 }
 
 type postcssTransformation struct {
-	options Options
+	optionsm map[string]any
 	rs       *resources.Spec
 }
 
 func (t *postcssTransformation) Key() internal.ResourceTransformationKey {
-	return internal.NewResourceTransformationKey("postcss", t.options)
+	return internal.NewResourceTransformationKey("postcss", t.optionsm)
 }
 
 // Transform shells out to postcss-cli to do the heavy lifting.
@@ -157,8 +157,17 @@ func (t *postcssTransformation) Transform(ctx *resources.ResourceTransformationC
 	var configFile string
 	logger := t.rs.Logger
 
-	if t.options.Config != "" {
-		configFile = t.options.Config
+	var options Options
+	if t.optionsm != nil {
+		var err error
+		options, err = decodeOptions(t.optionsm)
+		if err != nil {
+			return err
+		}
+	}
+
+	if options.Config != "" {
+		configFile = options.Config
 	} else {
 		configFile = "postcss.config.js"
 	}
@@ -168,9 +177,9 @@ func (t *postcssTransformation) Transform(ctx *resources.ResourceTransformationC
 	// We need an absolute filename to the config file.
 	if !filepath.IsAbs(configFile) {
 		configFile = t.rs.BaseFs.ResolveJSConfigFile(configFile)
-		if configFile == "" && t.options.Config != "" {
+		if configFile == "" && options.Config != "" {
 			// Only fail if the user specified config file is not found.
-			return fmt.Errorf("postcss config %q not found:", t.options.Config)
+			return fmt.Errorf("postcss config %q not found:", options.Config)
 		}
 	}
 
@@ -181,7 +190,7 @@ func (t *postcssTransformation) Transform(ctx *resources.ResourceTransformationC
 		cmdArgs = []any{"--config", configFile}
 	}
 
-	if optArgs := t.options.toArgs(); len(optArgs) > 0 {
+	if optArgs := options.toArgs(); len(optArgs) > 0 {
 		cmdArgs = append(cmdArgs, collections.StringSliceToInterfaceSlice(optArgs)...)
 	}
 
@@ -212,11 +221,11 @@ func (t *postcssTransformation) Transform(ctx *resources.ResourceTransformationC
 	imp := newImportResolver(
 		ctx.From,
 		ctx.InPath,
-		t.options,
+		options,
 		t.rs.Assets.Fs, t.rs.Logger,
 	)
 
-	if t.options.InlineImports {
+	if options.InlineImports {
 		var err error
 		src, err = imp.resolve()
 		if err != nil {

resources/resource_transformers/postcss/postcss_test.go

@@ -31,14 +31,14 @@ import (
 // Issue 6166
 func TestDecodeOptions(t *testing.T) {
 	c := qt.New(t)
-	opts1, err := DecodeOptions(map[string]any{
+	opts1, err := decodeOptions(map[string]any{
 		"no-map": true,
 	})
 
 	c.Assert(err, qt.IsNil)
 	c.Assert(opts1.NoMap, qt.Equals, true)
 
-	opts2, err := DecodeOptions(map[string]any{
+	opts2, err := decodeOptions(map[string]any{
 		"noMap": true,
 	})
 

tpl/resources/resources.go

@@ -405,15 +405,8 @@ func (ns *Namespace) PostCSS(args ...any) (resource.Resource, error) {
 	if err != nil {
 		return nil, err
 	}
-	var options postcss.Options
-	if m != nil {
-		options, err = postcss.DecodeOptions(m)
-		if err != nil {
-			return nil, err
-		}
-	}
 
-	return ns.postcssClient.Process(r, options)
+	return ns.postcssClient.Process(r, m)
 }
 
 func (ns *Namespace) PostProcess(r resource.Resource) (postpub.PostPublishedResource, error) {