commands: Fix environment isolation for configuration settings

Closes #14763

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

commands/commandeer.go

@@ -153,6 +153,23 @@ type rootCommand struct {
 	cfgDir  string
 }
 
+// resolveEnvironment sets r.environment if not already set.
+// server indicates whether the server command is running (defaults to development).
+func (r *rootCommand) resolveEnvironment(server bool) {
+	if r.environment != "" {
+		return
+	}
+	if env := os.Getenv("HUGO_ENVIRONMENT"); env != "" {
+		r.environment = env
+	} else if env := os.Getenv("HUGO_ENV"); env != "" {
+		r.environment = env
+	} else if server {
+		r.environment = hugo.EnvironmentDevelopment
+	} else {
+		r.environment = hugo.EnvironmentProduction
+	}
+}
+
 func (r *rootCommand) isVerbose() bool {
 	return r.logger.Level() <= logg.LevelInfo
 }
@@ -224,6 +241,7 @@ func (r *rootCommand) ConfigFromProvider(key configKey, cfg config.Provider) (*c
 	if cfg == nil {
 		panic("cfg must be set")
 	}
+	r.resolveEnvironment(false)
 	cc, _, err := r.commonConfigs.GetOrCreate(key, func(key configKey) (*commonConfig, error) {
 		var dir string
 		if r.source != "" {

commands/hugobuilder.go

@@ -1082,22 +1082,8 @@ func (c *hugoBuilder) loadConfig(cd *simplecobra.Commandeer, running bool) error
 	cfg := config.New()
 	cfg.Set("renderToMemory", c.r.renderToMemory)
 	watch := c.r.buildWatch || (c.s != nil && c.s.serverWatch)
-	if c.r.environment == "" {
-		// We need to set the environment as early as possible because we need it to load the correct config.
-		// Check if the user has set it in env.
-		if env := os.Getenv("HUGO_ENVIRONMENT"); env != "" {
-			c.r.environment = env
-		} else if env := os.Getenv("HUGO_ENV"); env != "" {
-			c.r.environment = env
-		} else {
-			if c.s != nil {
-				// The server defaults to development.
-				c.r.environment = hugo.EnvironmentDevelopment
-			} else {
-				c.r.environment = hugo.EnvironmentProduction
-			}
-		}
-	}
+	// We need to set the environment as early as possible because we need it to load the correct config.
+	c.r.resolveEnvironment(c.s != nil)
 	cfg.Set("environment", c.r.environment)
 
 	cfg.Set("internal", hmaps.Params{

testscripts/commands/config_environment_isolation_issue14763.txt

@@ -0,0 +1,23 @@
+# Issue 14763
+
+# The staging config should not apply.
+hugo config
+! stdout 'myparam'
+mkdir content
+hugo new content foo.md
+hugo -DF
+! grep 'foo' public/foo/index.html
+
+# The staging config should apply.
+hugo config -e staging
+stdout 'myparam'
+hugo new content bar.md -e staging
+hugo -DF -e staging
+grep 'myparam: foo|' public/bar/index.html
+
+-- config/_default/hugo.toml --
+baseURL = "https://example.com"
+-- config/staging/params.toml --
+myparam = "foo"
+-- layouts/single.html --
+myparam: {{ site.Params.myparam }}|