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

3 files changed, 25 insertions, 23 deletions

diff --git a/resources/resource_transformers/postcss/postcss.go b/resources/resource_transformers/postcss/postcss.go
index adf2b5164..eab52b8c5 100644
--- a/resources/resource_transformers/postcss/postcss.go
+++ b/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
-	rs      *resources.Spec
+	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 {
diff --git a/resources/resource_transformers/postcss/postcss_test.go b/resources/resource_transformers/postcss/postcss_test.go
index f5d49300a..6901d69de 100644
--- a/resources/resource_transformers/postcss/postcss_test.go
+++ b/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,
 	})
 
diff --git a/tpl/resources/resources.go b/tpl/resources/resources.go
index 165152c78..428e36c92 100644
--- a/tpl/resources/resources.go
+++ b/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) {