fix: Make --chdir flag work with terraform/helmfile/packer commands (#1767)

* fix: Make --chdir flag work with terraform/helmfile/packer commands

This commit fixes the --chdir flag to work correctly with commands that have
DisableFlagParsing=true (terraform, helmfile, packer).

The issue was that Cobra doesn't parse flags when DisableFlagParsing=true, but
PersistentPreRun runs before the command's Run function where flags would be
manually parsed. This meant --chdir was not processed before atmos.yaml was loaded.

The fix adds parseChdirFromArgs() which manually parses --chdir or -C from os.Args,
supporting all formats: --chdir=path, -C=path, -Cpath, --chdir path, -C path.

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

Co-Authored-By: Claude <[email protected]>

* test: Add comprehensive tests for parseChdirFromArgs function

Add 14 test cases covering all argument parsing formats:
- --chdir=path, --chdir path
- -C=path, -C path, -Cpath
- Relative paths, tilde expansion
- Edge cases (missing values, multiple flags, empty args)

This improves test coverage for the chdir flag parsing logic
that is critical for terraform/helmfile/packer commands.

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

Co-Authored-By: Claude <[email protected]>

---------

Co-authored-by: Claude <[email protected]>

Author: osterman

cmd/root.go

@@ -62,11 +62,52 @@ var profilerServer *profiler.Server
 // logFileHandle holds the opened log file for the lifetime of the program.
 var logFileHandle *os.File
 
+// parseChdirFromArgs manually parses --chdir or -C flag from os.Args.
+// This is needed for commands with DisableFlagParsing=true (terraform, helmfile, packer)
+// where Cobra doesn't parse flags before PersistentPreRun is called.
+func parseChdirFromArgs() string {
+	args := os.Args
+	for i := 0; i < len(args); i++ {
+		arg := args[i]
+
+		// Check for --chdir=value format.
+		if strings.HasPrefix(arg, "--chdir=") {
+			return strings.TrimPrefix(arg, "--chdir=")
+		}
+
+		// Check for -C=value format.
+		if strings.HasPrefix(arg, "-C=") {
+			return strings.TrimPrefix(arg, "-C=")
+		}
+
+		// Check for -C<value> format (concatenated, e.g., -C../foo).
+		if strings.HasPrefix(arg, "-C") && len(arg) > 2 {
+			return arg[2:]
+		}
+
+		// Check for --chdir value or -C value format (next arg is the value).
+		if arg == "--chdir" || arg == "-C" {
+			if i+1 < len(args) {
+				return args[i+1]
+			}
+		}
+	}
+	return ""
+}
+
 // processChdirFlag processes the --chdir flag and ATMOS_CHDIR environment variable,
 // changing the working directory before any other operations.
 // Precedence: --chdir flag > ATMOS_CHDIR environment variable.
 func processChdirFlag(cmd *cobra.Command) error {
+	// Try to get chdir from parsed flags first (works when DisableFlagParsing=false).
 	chdir, _ := cmd.Flags().GetString("chdir")
+
+	// If flag parsing is disabled (terraform/helmfile/packer commands), manually parse os.Args.
+	// This is necessary because Cobra doesn't parse flags when DisableFlagParsing=true,
+	// but PersistentPreRun runs before the command's Run function where flags would be manually parsed.
+	if chdir == "" {
+		chdir = parseChdirFromArgs()
+	}
 	// If flag is not set, check environment variable.
 	// Note: chdir is not supported in atmos.yaml since it must be processed before atmos.yaml is loaded.
 	if chdir == "" {

cmd/root_test.go

@@ -516,3 +516,103 @@ func TestIsCompletionCommand(t *testing.T) {
 		})
 	}
 }
+
+// TestParseChdirFromArgs tests the parseChdirFromArgs function that manually parses --chdir or -C flags.
+// This function is critical for commands with DisableFlagParsing=true (terraform, helmfile, packer).
+func TestParseChdirFromArgs(t *testing.T) {
+	tests := []struct {
+		name     string
+		args     []string
+		expected string
+	}{
+		{
+			name:     "--chdir with equals sign",
+			args:     []string{"atmos", "--chdir=/tmp/foo", "terraform", "plan"},
+			expected: "/tmp/foo",
+		},
+		{
+			name:     "--chdir with space",
+			args:     []string{"atmos", "--chdir", "/tmp/bar", "terraform", "plan"},
+			expected: "/tmp/bar",
+		},
+		{
+			name:     "-C with equals sign",
+			args:     []string{"atmos", "-C=/tmp/baz", "terraform", "plan"},
+			expected: "/tmp/baz",
+		},
+		{
+			name:     "-C with space",
+			args:     []string{"atmos", "-C", "/tmp/qux", "terraform", "plan"},
+			expected: "/tmp/qux",
+		},
+		{
+			name:     "-C concatenated (no space or equals)",
+			args:     []string{"atmos", "-C/tmp/concat", "terraform", "plan"},
+			expected: "/tmp/concat",
+		},
+		{
+			name:     "-C concatenated with relative path",
+			args:     []string{"atmos", "-C../foo", "terraform", "plan"},
+			expected: "../foo",
+		},
+		{
+			name:     "no chdir flag",
+			args:     []string{"atmos", "terraform", "plan"},
+			expected: "",
+		},
+		{
+			name:     "--chdir at end without value",
+			args:     []string{"atmos", "terraform", "plan", "--chdir"},
+			expected: "",
+		},
+		{
+			name:     "-C at end without value",
+			args:     []string{"atmos", "terraform", "plan", "-C"},
+			expected: "",
+		},
+		{
+			name:     "multiple --chdir flags (first wins)",
+			args:     []string{"atmos", "--chdir=/first", "--chdir=/second", "terraform", "plan"},
+			expected: "/first",
+		},
+		{
+			name:     "mixed -C and --chdir (first wins)",
+			args:     []string{"atmos", "-C/first", "--chdir=/second", "terraform", "plan"},
+			expected: "/first",
+		},
+		{
+			name:     "--chdir with tilde",
+			args:     []string{"atmos", "--chdir=~/mydir", "terraform", "plan"},
+			expected: "~/mydir",
+		},
+		{
+			name:     "empty args",
+			args:     []string{},
+			expected: "",
+		},
+		{
+			name:     "single arg",
+			args:     []string{"atmos"},
+			expected: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Save and restore os.Args.
+			originalArgs := os.Args
+			defer func() { os.Args = originalArgs }()
+
+			// Set os.Args to the test args.
+			os.Args = tt.args
+
+			// Call the function.
+			result := parseChdirFromArgs()
+
+			// Verify.
+			assert.Equal(t, tt.expected, result,
+				"parseChdirFromArgs() with args %v should return %q, got %q",
+				tt.args, tt.expected, result)
+		})
+	}
+}