fix(cli): make --purchase execute real purchases (--dry-run defaults false)

The --dry-run flag defaulted to true, so effectiveDryRun (!ActualPurchase
|| DryRun) stayed true even when --purchase was given -- meaning --purchase
alone never executed real purchases, defeating the flag. Default --dry-run
to false; the safe default is preserved because ActualPurchase defaults to
false (a bare invocation is still dry-run). Passing --dry-run alongside
--purchase still forces dry-run as an explicit safety override.

Adds a regression test that fails on the prior true default and covers all
four flag combinations.

Author: cristim

cmd/effective_dry_run_test.go

@@ -0,0 +1,47 @@
+package main
+
+import "testing"
+
+// TestEffectiveDryRun documents the flag contract for real purchases and guards
+// the regression where `--purchase` alone silently stayed in dry-run because
+// `--dry-run` defaulted to true (effectiveDryRun = !ActualPurchase || DryRun,
+// so !true || true == true). The default for --dry-run is now false; safety is
+// preserved by ActualPurchase defaulting to false (a bare run is still dry-run).
+func TestEffectiveDryRun(t *testing.T) {
+	tests := []struct {
+		name           string
+		actualPurchase bool // --purchase
+		dryRun         bool // --dry-run (default false)
+		want           bool
+	}{
+		{name: "bare invocation is dry-run", actualPurchase: false, dryRun: false, want: true},
+		{name: "--purchase executes real purchases", actualPurchase: true, dryRun: false, want: false},
+		{name: "--purchase --dry-run forces dry-run (explicit safety override)", actualPurchase: true, dryRun: true, want: true},
+		{name: "--dry-run without --purchase stays dry-run", actualPurchase: false, dryRun: true, want: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := effectiveDryRun(Config{ActualPurchase: tt.actualPurchase, DryRun: tt.dryRun})
+			if got != tt.want {
+				t.Errorf("effectiveDryRun(ActualPurchase=%v, DryRun=%v) = %v, want %v",
+					tt.actualPurchase, tt.dryRun, got, tt.want)
+			}
+		})
+	}
+}
+
+// TestDryRunFlagDefaultIsFalse guards the actual fix: the --dry-run flag must
+// default to false. When it defaulted to true, `--purchase` alone resolved to
+// effectiveDryRun == true (!ActualPurchase || DryRun => !true || true), so real
+// purchases never executed. A bare run stays dry-run via ActualPurchase's own
+// false default, so flipping this default is safe.
+func TestDryRunFlagDefaultIsFalse(t *testing.T) {
+	f := rootCmd.Flags().Lookup("dry-run")
+	if f == nil {
+		t.Fatal("--dry-run flag not registered")
+	}
+	if f.DefValue != "false" {
+		t.Errorf("--dry-run default = %q, want \"false\" (so --purchase alone executes real purchases)", f.DefValue)
+	}
+}

cmd/main.go

@@ -134,7 +134,7 @@ func init() {
 
 	// Purchase pipeline flags
 	rootCmd.Flags().StringVar(&toolCfg.AuditLog, "audit-log", "./cudly-audit.jsonl", "Path to JSONL audit log file")
-	rootCmd.Flags().BoolVar(&toolCfg.DryRun, "dry-run", true, "Dry-run mode: show what would be purchased without actually buying")
+	rootCmd.Flags().BoolVar(&toolCfg.DryRun, "dry-run", false, "Force dry-run even when --purchase is set (runs are already dry-run unless --purchase is given)")
 	rootCmd.Flags().StringVar(&toolCfg.IdempotencyWindow, "idempotency-window", "24h", "Lookback window for duplicate purchase detection")
 	rootCmd.Flags().Float64Var(&toolCfg.MinSavingsPct, "min-savings-pct", 0, "Minimum savings percentage to include a recommendation (0 = no filter)")
 	rootCmd.Flags().IntVar(&toolCfg.MaxBreakEvenMonths, "max-break-even-months", 0, "Maximum break-even period in months (0 = no filter)")

cmd/multi_service.go

@@ -71,9 +71,14 @@ func fetchExistingCoverage(ctx context.Context, awsCfg aws.Config, recClient pro
 // shutdownRequested is set to true when SIGINT is received during a purchase run.
 var shutdownRequested atomic.Bool
 
-// effectiveDryRun returns true when either DryRun is explicitly set or
-// ActualPurchase is not enabled. Both the non-CSV and CSV code paths use
-// this helper so the guard is consistent and defined in one place.
+// effectiveDryRun reports whether the run must stay in dry-run mode. A run is
+// dry-run unless the user opts into real purchases with --purchase; passing
+// --dry-run additionally forces dry-run even alongside --purchase (an explicit
+// safety override). --dry-run defaults to false so that --purchase alone
+// actually executes purchases; the safe default is preserved because
+// ActualPurchase defaults to false, so a bare invocation is still dry-run.
+// Both the non-CSV and CSV code paths use this helper so the guard is
+// consistent and defined in one place.
 func effectiveDryRun(cfg Config) bool {
 	return !cfg.ActualPurchase || cfg.DryRun
 }