feat(platform): add Reinstall helpers to Pacman and Yay

internal/platform/aur.go

@@ -52,6 +52,17 @@ func (y *Yay) Install(ctx context.Context, pkgs []string) error {
 	return y.Runner.Run(ctx, "yay", args...)
 }
 
+// Reinstall runs `yay -S --noconfirm <pkgs...>` WITHOUT `--needed`, forcing
+// yay/pacman to re-fetch and reinstall the packages even if already present.
+// Used by the `--force` flag to bypass idempotency.
+func (y *Yay) Reinstall(ctx context.Context, pkgs []string) error {
+	if len(pkgs) == 0 {
+		return nil
+	}
+	args := append([]string{"-S", "--noconfirm"}, pkgs...)
+	return y.Runner.Run(ctx, "yay", args...)
+}
+
 func shellQuote(s string) string {
 	return "'" + strings.ReplaceAll(s, "'", `'\''`) + "'"
 }

internal/platform/aur_test.go

@@ -70,6 +70,32 @@ func TestAUREnsureInstalledBootstrapsYay(t *testing.T) {
 	}
 }
 
+func TestYayReinstall(t *testing.T) {
+	r := &aurFakeRunner{yayInstalled: true}
+	y := NewYay(r)
+	if err := y.Reinstall(context.Background(), []string{"git", "curl"}); err != nil {
+		t.Fatal(err)
+	}
+	if len(r.runCalls) == 0 {
+		t.Fatal("expected yay reinstall call")
+	}
+	c := r.runCalls[len(r.runCalls)-1]
+	want := []string{"yay", "-S", "--noconfirm", "git", "curl"}
+	if len(c) != len(want) {
+		t.Fatalf("call = %v, want %v", c, want)
+	}
+	for i, w := range want {
+		if c[i] != w {
+			t.Fatalf("call = %v, want %v", c, want)
+		}
+	}
+	for _, a := range c {
+		if a == "--needed" {
+			t.Fatalf("Reinstall must not pass --needed; got %v", c)
+		}
+	}
+}
+
 func TestAURInstall(t *testing.T) {
 	r := &aurFakeRunner{yayInstalled: true}
 	y := NewYay(r)

internal/platform/pacman.go

@@ -76,6 +76,17 @@ func (p Pacman) Install(ctx context.Context, pkgs []string) error {
 	return p.Runner.Run(ctx, "sudo", args...)
 }
 
+// Reinstall runs `sudo pacman -S --noconfirm <pkgs...>` WITHOUT `--needed`,
+// so pacman physically re-fetches and reinstalls the packages even if they
+// are already present. Used by the `--force` flag to bypass idempotency.
+func (p Pacman) Reinstall(ctx context.Context, pkgs []string) error {
+	if len(pkgs) == 0 {
+		return nil
+	}
+	args := append([]string{"pacman", "-S", "--noconfirm"}, pkgs...)
+	return p.Runner.Run(ctx, "sudo", args...)
+}
+
 // Update runs `sudo pacman -Syu --noconfirm` (full sync + system upgrade).
 // On Arch, a bare `pacman -Sy` followed by an install is the partial-upgrade
 // anti-pattern that can break the system when a dep's ABI changes, so we

internal/platform/pacman_test.go

@@ -39,6 +39,27 @@ func TestPacmanInstallShellsOutCorrectly(t *testing.T) {
 	}
 }
 
+func TestPacmanReinstall(t *testing.T) {
+	r := &fakeRunner{}
+	p := NewPacman(r)
+	if err := p.Reinstall(context.Background(), []string{"git", "curl"}); err != nil {
+		t.Fatal(err)
+	}
+	if len(r.runCalls) != 1 {
+		t.Fatalf("run calls = %d", len(r.runCalls))
+	}
+	got := r.runCalls[0]
+	want := []string{"sudo", "pacman", "-S", "--noconfirm", "git", "curl"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("args = %v, want %v", got, want)
+	}
+	for _, a := range got {
+		if a == "--needed" {
+			t.Fatalf("Reinstall must not pass --needed; got %v", got)
+		}
+	}
+}
+
 func TestPacmanInstallEmptyIsNoop(t *testing.T) {
 	r := &fakeRunner{}
 	p := NewPacman(r)