Fix OS env override for nested config param only available in theme

Fixes #8346

2 files changed, 52 insertions, 37 deletions

diff --git a/hugolib/config.go b/hugolib/config.go
index 5ef78acf4..fe138bf20 100644
--- a/hugolib/config.go
+++ b/hugolib/config.go
@@ -18,6 +18,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/common/types"
 
 	"github.com/gobwas/glob"
@@ -27,8 +28,6 @@ import (
 
 	"github.com/gohugoio/hugo/cache/filecache"
 
-	"github.com/gohugoio/hugo/common/maps"
-
 	"github.com/gohugoio/hugo/parser/metadecoders"
 
 	"github.com/gohugoio/hugo/common/herrors"
@@ -167,6 +166,40 @@ func LoadConfig(d ConfigSourceDescriptor, doWithConfig ...func(cfg config.Provid
 		}
 	}
 
+	// We made this a Glob pattern in Hugo 0.75, we don't need both.
+	if v.GetBool("ignoreVendor") {
+		helpers.Deprecated("--ignoreVendor", "--ignoreVendorPaths **", false)
+		v.Set("ignoreVendorPaths", "**")
+	}
+
+	modulesConfig, err := l.loadModulesConfig(v)
+	if err != nil {
+		return v, configFiles, err
+	}
+
+	// Need to run these after the modules are loaded, but before
+	// they are finalized.
+	collectHook := func(m *modules.ModulesConfig) error {
+		if err := loadLanguageSettings(v, nil); err != nil {
+			return err
+		}
+
+		mods := m.ActiveModules
+
+		// Apply default project mounts.
+		if err := modules.ApplyProjectConfigDefaults(v, mods[0]); err != nil {
+			return err
+		}
+
+		return nil
+	}
+
+	_, modulesConfigFiles, err := l.collectModules(modulesConfig, v, collectHook)
+
+	if err == nil && len(modulesConfigFiles) > 0 {
+		configFiles = append(configFiles, modulesConfigFiles...)
+	}
+
 	const delim = "__env__delim"
 
 	// Apply environment overrides
@@ -222,40 +255,6 @@ func LoadConfig(d ConfigSourceDescriptor, doWithConfig ...func(cfg config.Provid
 
 	}
 
-	// We made this a Glob pattern in Hugo 0.75, we don't need both.
-	if v.GetBool("ignoreVendor") {
-		helpers.Deprecated("--ignoreVendor", "--ignoreVendorPaths **", false)
-		v.Set("ignoreVendorPaths", "**")
-	}
-
-	modulesConfig, err := l.loadModulesConfig(v)
-	if err != nil {
-		return v, configFiles, err
-	}
-
-	// Need to run these after the modules are loaded, but before
-	// they are finalized.
-	collectHook := func(m *modules.ModulesConfig) error {
-		if err := loadLanguageSettings(v, nil); err != nil {
-			return err
-		}
-
-		mods := m.ActiveModules
-
-		// Apply default project mounts.
-		if err := modules.ApplyProjectConfigDefaults(v, mods[0]); err != nil {
-			return err
-		}
-
-		return nil
-	}
-
-	_, modulesConfigFiles, err := l.collectModules(modulesConfig, v, collectHook)
-
-	if err == nil && len(modulesConfigFiles) > 0 {
-		configFiles = append(configFiles, modulesConfigFiles...)
-	}
-
 	return v, configFiles, err
 }
 
diff --git a/hugolib/config_test.go b/hugolib/config_test.go
index ecb450067..75f5b9786 100644
--- a/hugolib/config_test.go
+++ b/hugolib/config_test.go
@@ -483,6 +483,7 @@ func TestLoadConfigWithOsEnvOverrides(t *testing.T) {
 
 	baseConfig := `
 
+theme = "mytheme"
 environment = "production"
 enableGitInfo = true
 intSlice = [5,7,9]
@@ -501,6 +502,16 @@ quality = 75
 
 	b := newTestSitesBuilder(t).WithConfigFile("toml", baseConfig)
 
+	b.WithSourceFile("themes/mytheme/config.toml", `
+
+[params]
+[params.mytheme_section]
+theme_param="themevalue"
+[params.mytheme_section2]
+theme_param="themevalue2"
+
+`)
+
 	b.WithEnviron(
 		"HUGO_ENVIRONMENT", "test",
 		"HUGO_NEW", "new", // key not in config.toml
@@ -510,10 +521,13 @@ quality = 75
 		"HUGO_STRINGSLICE", `["c", "d"]`,
 		"HUGO_INTSLICE", `[5, 8, 9]`,
 		"HUGO_FLOATSLICE", `[5.32]`,
-		// https://github.com/gohugoio/hugo/issues/7829
+		// Issue #7829
 		"HUGOxPARAMSxAPI_CONFIGxAPI_KEY", "new_key",
 		// Delimiters are case sensitive.
 		"HUGOxPARAMSxAPI_CONFIGXANOTHER_KEY", "another_key",
+		// Issue #8346
+		"HUGOxPARAMSxMYTHEME_SECTIONxTHEME_PARAM", "themevalue_changed",
+		"HUGOxPARAMSxMYTHEME_SECTION2xTHEME_PARAM", "themevalue2_changed",
 	)
 
 	b.Build(BuildCfg{})
@@ -531,4 +545,6 @@ quality = 75
 	c.Assert(cfg.Get("intSlice"), qt.DeepEquals, []interface{}{5, 8, 9})
 	c.Assert(cfg.Get("params.api_config.api_key"), qt.Equals, "new_key")
 	c.Assert(cfg.Get("params.api_config.another_key"), qt.Equals, "default another_key")
+	c.Assert(cfg.Get("params.mytheme_section.theme_param"), qt.Equals, "themevalue_changed")
+	c.Assert(cfg.Get("params.mytheme_section2.theme_param"), qt.Equals, "themevalue2_changed")
 }