Deduplicate config file write logic and use env.Get for consistency

Extract writeConfigFile helper to consolidate the repeated
default-comment, backup, and save sequence shared by SaveToProfile
and DeleteProfile.

Also switch auth login from os.Getenv to env.Get(ctx, ...) for
DATABRICKS_CONFIG_FILE so it respects context-level env overrides,
consistent with the rest of the codebase.

Author: mihaimitrea-db

cmd/auth/login.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"os"
 	"runtime"
 	"strings"
 	"time"
@@ -249,7 +248,7 @@ depends on the existing profiles you have set in your configuration file
 				WorkspaceID:                authArguments.WorkspaceID,
 				Experimental_IsUnifiedHost: authArguments.IsUnifiedHost,
 				ClusterID:                  clusterID,
-				ConfigFile:                 os.Getenv("DATABRICKS_CONFIG_FILE"),
+				ConfigFile:                 env.Get(ctx, "DATABRICKS_CONFIG_FILE"),
 				ServerlessComputeID:        serverlessComputeID,
 				Scopes:                     scopesList,
 			}, clearKeys...)

libs/databrickscfg/ops.go

@@ -94,6 +94,17 @@ func AuthCredentialKeys() []string {
 	return keys
 }
 
+func writeConfigFile(ctx context.Context, configFile *config.File) error {
+	section := configFile.Section(ini.DefaultSection)
+	if len(section.Keys()) == 0 && section.Comment == "" {
+		section.Comment = defaultComment
+	}
+	if err := backupConfigFile(ctx, configFile); err != nil {
+		return err
+	}
+	return configFile.SaveTo(configFile.Path())
+}
+
 func backupConfigFile(ctx context.Context, configFile *config.File) error {
 	orig, backupErr := os.ReadFile(configFile.Path())
 	if len(orig) > 0 && backupErr == nil {
@@ -147,16 +158,7 @@ func SaveToProfile(ctx context.Context, cfg *config.Config, clearKeys ...string)
 		key.SetValue(attr.GetString(cfg))
 	}
 
-	// Add a comment to the default section if it's empty.
-	section = configFile.Section(ini.DefaultSection)
-	if len(section.Keys()) == 0 && section.Comment == "" {
-		section.Comment = defaultComment
-	}
-
-	if err := backupConfigFile(ctx, configFile); err != nil {
-		return err
-	}
-	return configFile.SaveTo(configFile.Path())
+	return writeConfigFile(ctx, configFile)
 }
 
 // DeleteProfile removes the named profile section from the databrickscfg file.
@@ -175,15 +177,7 @@ func DeleteProfile(ctx context.Context, profileName, configFilePath string) erro
 
 	configFile.DeleteSection(profileName)
 
-	section := configFile.Section(ini.DefaultSection)
-	if len(section.Keys()) == 0 && section.Comment == "" {
-		section.Comment = defaultComment
-	}
-
-	if err := backupConfigFile(ctx, configFile); err != nil {
-		return err
-	}
-	return configFile.SaveTo(configFile.Path())
+	return writeConfigFile(ctx, configFile)
 }
 
 func ValidateConfigAndProfileHost(cfg *config.Config, profile string) error {