feat: Add ATMOS_PROFILE environment variable support and fix linter errors

## Profile Environment Variable Support

Added `ATMOS_PROFILE` environment variable support for setting active profiles:
- Added env var fallback in `internal/exec/cli_utils.go` for commands using ProcessCommandLineArgs
- Removed redundant env var handling from `cmd/root.go` (not used by most commands)
- Supports comma-separated profiles: `ATMOS_PROFILE="ci,developer"`
- Flag takes precedence over env var for consistent behavior
- Updated configuration documentation

## Linter Fixes

Fixed all lintroller and golangci-lint errors:
- Added missing `defer perf.Track()` in `pkg/flags/flag_parser.go:NormalizeShorthandWithEquals()`
- Fixed `Deprecated` field comment in `pkg/schema/schema.go` (removed colon to avoid deprecation marker)
- Removed unnecessary `os.Chdir` save/restore in `cmd/root_helpers_test.go` (tests don't change directory)
- Added `cmd/root_helpers_test.go` and `cmd/root_test.go` to lintroller exclusions for legitimate `os.Args` usage
  (these files test functions that directly read `os.Args`)

## Testing

All changes tested and verified:
- ✅ `ATMOS_PROFILE=developer` loads profile correctly
- ✅ `--profile` flag works
- ✅ Flag precedence over env var
- ✅ Comma-separated profiles work
- ✅ All unit tests pass
- ✅ All linter checks pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: aknysh

cmd/root_helpers_test.go

@@ -828,11 +828,6 @@ func TestRootCmd_RunE(t *testing.T) {
 	// This test verifies that the root command's RunE function
 	// properly handles configuration and prints the ATMOS logo.
 
-	// Save original state.
-	originalWd, err := os.Getwd()
-	assert.NoError(t, err)
-	defer os.Chdir(originalWd)
-
 	// Use test fixtures.
 	stacksPath := "../tests/fixtures/scenarios/complete"
 	t.Setenv("ATMOS_CLI_CONFIG_PATH", stacksPath)

cmd/version/list.go

@@ -152,7 +152,7 @@ var listCmd = &cobra.Command{
 		// Validate format.
 		normalizedFormat := strings.ToLower(listFormat)
 		if normalizedFormat != "table" && normalizedFormat != "json" && normalizedFormat != "yaml" {
-			return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrUnsupportedOutputFormat, listFormat)
+			return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrInvalidFormat, listFormat)
 		}
 
 		// Parse since date if provided.
@@ -188,7 +188,7 @@ var listCmd = &cobra.Command{
 		case "yaml":
 			return formatReleaseListYAML(releases)
 		default:
-			return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrUnsupportedOutputFormat, listFormat)
+			return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrInvalidFormat, listFormat)
 		}
 	},
 }

cmd/version/show.go

@@ -166,7 +166,7 @@ var showCmd = &cobra.Command{
 		case "yaml":
 			return formatReleaseDetailYAML(release)
 		default:
-			return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrUnsupportedOutputFormat, showFormat)
+			return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrInvalidFormat, showFormat)
 		}
 	},
 }

cmd/version/show_test.go

@@ -322,7 +322,7 @@ func TestShowCommand_FormatValidation(t *testing.T) {
 				case "yaml":
 					return formatReleaseDetailYAML(release)
 				default:
-					return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrUnsupportedOutputFormat, showFormat)
+					return fmt.Errorf("%w: %s (supported: table, json, yaml)", errUtils.ErrInvalidFormat, showFormat)
 				}
 			}
 

docs/prd/auth-default-settings.md

@@ -126,7 +126,6 @@ auth:
 auth:
   # NEW: Global settings for auth behavior
   settings:
-    default_identity: github-oidc-identity
     session_duration: "12h"
     console_session_duration: "8h"
     keyring_type: "system"
@@ -135,10 +134,12 @@ auth:
     # ... same as above
 
   identities:
+    github-oidc-identity:
+      default: true  # Current implementation uses identity-level default
     # ... same as above
 ```text
 
-**Note:** Less structured than Option 1, but flatter hierarchy.
+**Note:** Less structured than Option 1, but flatter hierarchy. Default identity selection uses the existing `identity.default: true` field.
 
 ## Detailed Design (Option 1 - Recommended)
 
@@ -670,15 +671,17 @@ ATMOS_DEFAULT_IDENTITY=github-oidc-identity
 ```yaml
 profiles:
   ci:
-    default_identity: github-oidc-identity
+    auth:
+      identities:
+        github-oidc-identity:
+          default: true
 ```text
 
 **Pros:**
 - Clear profile scope
-- Separate from auth config
+- Uses existing identity default mechanism
 
 **Cons:**
-- Breaks auth config encapsulation
 - Profile needs to know about auth internals
 - Doesn't solve global session defaults
 

docs/prd/describe-commands-identity-flag.md

@@ -541,11 +541,13 @@ if err := viper.BindEnv("identity", "ATMOS_IDENTITY", "IDENTITY"); err != nil {
 
 ### Default Identity
 
-Consider supporting default identity in `atmos.yaml`:
+Default identity is supported via the `default` field on identities in `atmos.yaml`:
 
 ```yaml
 auth:
-  default_identity: core-auto/terraform
+  identities:
+    core-auto/terraform:
+      default: true
 ```
 
 ### Identity Caching

errors/errors.go

@@ -52,7 +52,6 @@ var (
 	ErrInvalidOffset                         = errors.New("offset must be >= 0")
 	ErrDuplicateFlagRegistration             = errors.New("duplicate flag registration")
 	ErrInvalidSinceDate                      = errors.New("invalid date format for --since")
-	ErrUnsupportedOutputFormat               = errors.New("unsupported output format")
 	ErrTerminalTooNarrow                     = errors.New("terminal too narrow")
 	ErrSpinnerReturnedNilModel               = errors.New("spinner returned nil model")
 	ErrSpinnerUnexpectedModelType            = errors.New("spinner returned unexpected model type")

internal/exec/cli_utils.go

@@ -72,6 +72,7 @@ var commonFlags = []string{
 	cfg.ProfilerTypeFlag,
 	cfg.HeatmapFlag,
 	cfg.HeatmapModeFlag,
+	cfg.AuthProfileFlag,
 }
 
 // ProcessCommandLineArgs processes command-line args.
@@ -116,10 +117,24 @@ func ProcessCommandLineArgs(
 	if err != nil {
 		return configAndStacksInfo, err
 	}
-	configAndStacksInfo.ProfilesFromArg, err = cmd.Flags().GetStringSlice("profile")
+	// Read profile flag and env var.
+	// Check flag first, then fall back to ATMOS_PROFILE env var if flag not set.
+	profiles, err := cmd.Flags().GetStringSlice("profile")
 	if err != nil {
 		return configAndStacksInfo, err
 	}
+	if len(profiles) == 0 {
+		//nolint:forbidigo // Must use os.Getenv: profile is processed before Viper configuration loads.
+		if envProfiles := os.Getenv("ATMOS_PROFILE"); envProfiles != "" {
+			// Split comma-separated profiles from env var.
+			profiles = strings.Split(envProfiles, ",")
+			// Trim whitespace from each profile name.
+			for i := range profiles {
+				profiles[i] = strings.TrimSpace(profiles[i])
+			}
+		}
+	}
+	configAndStacksInfo.ProfilesFromArg = profiles
 	finalAdditionalArgsAndFlags := argsAndFlagsInfo.AdditionalArgsAndFlags
 	if len(additionalArgsAndFlags) > 0 {
 		finalAdditionalArgsAndFlags = append(finalAdditionalArgsAndFlags, additionalArgsAndFlags...)

pkg/config/const.go

@@ -144,4 +144,7 @@ const (
 	ProfilerTypeFlag    = "--profiler-type"
 	HeatmapFlag         = "--heatmap"
 	HeatmapModeFlag     = "--heatmap-mode"
+
+	// Auth profile flags.
+	AuthProfileFlag = "--profile"
 )

pkg/config/load.go

@@ -108,7 +108,7 @@ func LoadConfig(configAndStacksInfo *schema.ConfigAndStacksInfo) (schema.AtmosCo
 			return atmosConfig, err
 		}
 
-		log.Info("Profiles loaded successfully",
+		log.Debug("Profiles loaded successfully",
 			"profiles", configAndStacksInfo.ProfilesFromArg,
 			"count", len(configAndStacksInfo.ProfilesFromArg))
 	}