Add AssumeYes opt-in for unattended installs

Interactive tools prompt for confirmation and abort when no terminal is
attached, so unattended callers stall on 'Is this ok [y/N]:'. Add an
AssumeYes toggle, mirroring UseSudoWhenNeeded, that injects each manager's
non-interactive confirmation flag (-y, --noconfirm, --non-interactive) into
Install, Remove, Upgrade, InstallFile, and UpgradeAll. A flag already
supplied by the caller is not duplicated.

README.md

@@ -102,6 +102,7 @@ I/O take a `context.Context` for cancellation and timeouts.
 
 - **Identity:** `Name`, `Format`, `Path`
 - **Privilege:** `SetCmdWrapper`, `UseSudoWhenNeeded`
+- **Prompts:** `AssumeYes` (answer confirmation prompts automatically)
 - **I/O:** `SetIO` (override stdin/stdout/stderr of spawned commands)
 - **Repos:** `AddRepo`, `AddRepoURL`, `RemoveRepo`, `GetRepo`, `ListRepos`
 - **Keys:** `AddRepoKey`, `AddRepoKeyFile`, `AddRepoKeyURL`
@@ -130,6 +131,16 @@ Two mechanisms cover opposite requirements:
 A custom command wrapper (for example `[]string{"sudo", "-n"}`) can be supplied
 through `SetCmdWrapper`.
 
+## Unattended operation
+
+By default the managers run their tools interactively, so a mutating operation
+prompts for confirmation and aborts when no terminal is attached. `AssumeYes`
+enables unattended mode: each manager injects its own non-interactive
+confirmation flag (`-y` for `dnf`/`yum`/`apt`, `--noconfirm` for `pacman`/AUR
+helpers, `--non-interactive` for `zypper`) into `Install`, `Remove`, `Upgrade`,
+`InstallFile`, and `UpgradeAll`. A flag supplied explicitly through a method's
+`args` is not duplicated.
+
 ## Testing
 
 ```bash

apt-get.go

@@ -43,12 +43,12 @@ func (p *AptGet) Sync(ctx context.Context, args []string) error {
 
 // Install installs packages from the repositories.
 func (p *AptGet) Install(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "install"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "install"), packages...)...)
 }
 
 // Remove removes packages.
 func (p *AptGet) Remove(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "remove"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "remove"), packages...)...)
 }
 
 // Upgrade upgrades the named packages.
@@ -63,7 +63,7 @@ func (p *AptGet) InstallFile(ctx context.Context, args []string, packages ...str
 
 // UpgradeAll upgrades all packages with available updates.
 func (p *AptGet) UpgradeAll(ctx context.Context, args []string) error {
-	return p.exec(ctx, joinArgs(args, "upgrade")...)
+	return p.exec(ctx, joinArgs(p.confirmArgs(args, "-y"), "upgrade")...)
 }
 
 // Clean removes the local package cache.

apt.go

@@ -42,12 +42,12 @@ func (p *Apt) Sync(ctx context.Context, args []string) error {
 
 // Install installs packages from the repositories.
 func (p *Apt) Install(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "install"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "install"), packages...)...)
 }
 
 // Remove removes packages.
 func (p *Apt) Remove(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "remove"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "remove"), packages...)...)
 }
 
 // Upgrade upgrades the named packages.
@@ -62,7 +62,7 @@ func (p *Apt) InstallFile(ctx context.Context, args []string, packages ...string
 
 // UpgradeAll upgrades all packages with available updates.
 func (p *Apt) UpgradeAll(ctx context.Context, args []string) error {
-	return p.exec(ctx, joinArgs(args, "upgrade")...)
+	return p.exec(ctx, joinArgs(p.confirmArgs(args, "-y"), "upgrade")...)
 }
 
 // Clean removes the local package cache.

aur.go

@@ -55,12 +55,12 @@ func (p *aurBase) Sync(ctx context.Context, args []string) error {
 
 // Install installs packages from the repositories and the AUR.
 func (p *aurBase) Install(ctx context.Context, args []string, packages ...string) error {
-	return p.aurExec(ctx, append(joinArgs(args, "-S"), packages...)...)
+	return p.aurExec(ctx, append(joinArgs(p.confirmArgs(args, "--noconfirm"), "-S"), packages...)...)
 }
 
 // Remove removes packages.
 func (p *aurBase) Remove(ctx context.Context, args []string, packages ...string) error {
-	return p.aurExec(ctx, append(joinArgs(args, "-R"), packages...)...)
+	return p.aurExec(ctx, append(joinArgs(p.confirmArgs(args, "--noconfirm"), "-R"), packages...)...)
 }
 
 // Upgrade upgrades the named packages.
@@ -70,12 +70,12 @@ func (p *aurBase) Upgrade(ctx context.Context, args []string, packages ...string
 
 // InstallFile installs a package from a local file.
 func (p *aurBase) InstallFile(ctx context.Context, args []string, packages ...string) error {
-	return p.aurExec(ctx, append(joinArgs(args, "-U"), packages...)...)
+	return p.aurExec(ctx, append(joinArgs(p.confirmArgs(args, "--noconfirm"), "-U"), packages...)...)
 }
 
 // UpgradeAll upgrades all packages with available updates, including the AUR.
 func (p *aurBase) UpgradeAll(ctx context.Context, args []string) error {
-	return p.aurExec(ctx, joinArgs(args, "-Syu")...)
+	return p.aurExec(ctx, joinArgs(p.confirmArgs(args, "--noconfirm"), "-Syu")...)
 }
 
 // Search searches the repositories and the AUR for packages matching query. The

dnf.go

@@ -40,17 +40,17 @@ func (p *Dnf) Sync(ctx context.Context, args []string) error {
 
 // Install installs packages from the repositories.
 func (p *Dnf) Install(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "install"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "install"), packages...)...)
 }
 
 // Remove removes packages.
 func (p *Dnf) Remove(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "remove"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "remove"), packages...)...)
 }
 
 // Upgrade upgrades the named packages.
 func (p *Dnf) Upgrade(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "upgrade"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "upgrade"), packages...)...)
 }
 
 // InstallFile installs a package from a local file.
@@ -60,7 +60,7 @@ func (p *Dnf) InstallFile(ctx context.Context, args []string, packages ...string
 
 // UpgradeAll upgrades all packages with available updates.
 func (p *Dnf) UpgradeAll(ctx context.Context, args []string) error {
-	return p.exec(ctx, joinArgs(args, "upgrade")...)
+	return p.exec(ctx, joinArgs(p.confirmArgs(args, "-y"), "upgrade")...)
 }
 
 // Clean removes cached repository metadata and packages.

helpers.go

@@ -130,6 +130,17 @@ func joinArgs(args []string, extra ...string) []string {
 	return out
 }
 
+// containsArg reports whether args already contains flag, used to avoid
+// duplicating a confirmation flag the caller supplied explicitly.
+func containsArg(args []string, flag string) bool {
+	for _, a := range args {
+		if a == flag {
+			return true
+		}
+	}
+	return false
+}
+
 // writeRepoFile writes config to filePath, creating parent directories.
 func writeRepoFile(filePath, config string) error {
 	if err := os.MkdirAll(filepath.Dir(filePath), 0755); err != nil {

manager_test.go

@@ -79,6 +79,71 @@ func TestJoinArgsDoesNotMutate(t *testing.T) {
 	assert.Equal(t, []string{"-y", "install", "vim"}, got)
 }
 
+func TestConfirmArgs(t *testing.T) {
+	var b baseManager
+
+	// Off by default: args pass through untouched.
+	assert.Equal(t, []string{"install"}, b.confirmArgs([]string{"install"}, "-y"))
+
+	b.AssumeYes()
+
+	// On: the flag is prepended so it precedes the subcommand.
+	assert.Equal(t, []string{"-y", "install"}, b.confirmArgs([]string{"install"}, "-y"))
+
+	// A flag the caller already supplied is not duplicated.
+	assert.Equal(t, []string{"-y", "install"}, b.confirmArgs([]string{"-y", "install"}, "-y"))
+
+	// Multiple flags are all injected, preserving order.
+	assert.Equal(t, []string{"-a", "-b", "-S"}, b.confirmArgs([]string{"-S"}, "-a", "-b"))
+
+	// The caller's slice is not mutated, even with spare capacity.
+	in := make([]string, 1, 8)
+	in[0] = "install"
+	_ = b.confirmArgs(in, "-y")
+	assert.Equal(t, []string{"install"}, in, "confirmArgs mutated its input")
+}
+
+// TestAssumeYesInjectsConfirmFlag verifies that, with AssumeYes enabled, each
+// manager places its own non-interactive confirmation flag ahead of the
+// subcommand so an unattended install does not stall on a prompt. A fake binary
+// on PATH records the arguments it receives.
+func TestAssumeYesInjectsConfirmFlag(t *testing.T) {
+	cases := []struct {
+		name string
+		bin  string
+		newM func() Manager
+		want []string
+	}{
+		{"dnf", "dnf", func() Manager { return &Dnf{} }, []string{"-y", "install", "vim"}},
+		{"yum", "yum", func() Manager { return &Yum{} }, []string{"-y", "install", "vim"}},
+		{"apt", "apt", func() Manager { return &Apt{} }, []string{"-y", "install", "vim"}},
+		{"apt-get", "apt-get", func() Manager { return &AptGet{} }, []string{"-y", "install", "vim"}},
+		{"pacman", "pacman", func() Manager { return &Pacman{} }, []string{"--noconfirm", "-S", "vim"}},
+		// zypper's --non-interactive is a global option that must precede the
+		// subcommand, which prepending guarantees.
+		{"zypper", "zypper", func() Manager { return &Zypper{} }, []string{"--non-interactive", "install", "vim"}},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			dir := t.TempDir()
+			marker := filepath.Join(dir, "args")
+			// The fake binary records each argument on its own line, then exits 0.
+			script := "#!/bin/sh\nprintf '%s\\n' \"$@\" > " + marker + "\n"
+			require.NoError(t, os.WriteFile(filepath.Join(dir, tc.bin), []byte(script), 0755))
+			t.Setenv("PATH", dir)
+
+			m := tc.newM()
+			m.AssumeYes()
+			require.NoError(t, m.Install(context.Background(), nil, "vim"))
+
+			data, err := os.ReadFile(marker)
+			require.NoError(t, err, "manager did not invoke the binary")
+			assert.Equal(t, tc.want, strings.Fields(string(data)))
+		})
+	}
+}
+
 func TestParseVersionList(t *testing.T) {
 	in := "git := 1:2.39.0\nfoo := 0:1.0\nmalformed line\n\n  bar  :=  2.0 \n"
 	got, err := parseVersionList(strings.NewReader(in), " := ", true)

managers.go

@@ -32,6 +32,11 @@ type Manager interface {
 	// root. It is a no-op as root, and managers that must not run as root
 	// (brew, yay, paru) bypass the wrapper for their own command.
 	UseSudoWhenNeeded()
+	// AssumeYes enables unattended operation so state-changing commands answer
+	// their confirmation prompt automatically. It is required when the manager
+	// runs without a controlling terminal, where an unanswered prompt aborts
+	// the operation.
+	AssumeYes()
 	// SetIO overrides the stdin, stdout, and stderr used by spawned commands.
 	// Passing nil for a stream restores its os default.
 	SetIO(stdin io.Reader, stdout, stderr io.Writer)
@@ -102,10 +107,11 @@ func GetSystemManager() Manager {
 
 // baseManager holds state and helpers shared by every manager implementation.
 type baseManager struct {
-	wrapper []string
-	stdin   io.Reader
-	stdout  io.Writer
-	stderr  io.Writer
+	wrapper   []string
+	assumeYes bool
+	stdin     io.Reader
+	stdout    io.Writer
+	stderr    io.Writer
 }
 
 // SetCmdWrapper sets a command wrapper, for example []string{"sudo"}.
@@ -120,6 +126,33 @@ func (p *baseManager) SetIO(stdin io.Reader, stdout, stderr io.Writer) {
 	p.stderr = stderr
 }
 
+// AssumeYes enables unattended operation so state-changing commands answer
+// their confirmation prompt automatically. It is an opt-in toggle honored by
+// each manager's Install, Remove, Upgrade, InstallFile, and UpgradeAll methods.
+func (p *baseManager) AssumeYes() {
+	p.assumeYes = true
+}
+
+// confirmArgs prepends the manager's non-interactive confirmation flags to args
+// when AssumeYes is enabled, so an unattended run does not stall on a prompt. It
+// returns args unchanged when the toggle is off, and never duplicates a flag the
+// caller already supplied.
+func (p *baseManager) confirmArgs(args []string, flags ...string) []string {
+	if !p.assumeYes {
+		return args
+	}
+	var prefix []string
+	for _, f := range flags {
+		if !containsArg(args, f) {
+			prefix = append(prefix, f)
+		}
+	}
+	if len(prefix) == 0 {
+		return args
+	}
+	return append(prefix, args...)
+}
+
 // stdinOrDefault returns the configured stdin, or os.Stdin when unset.
 func (p *baseManager) stdinOrDefault() io.Reader {
 	if p.stdin != nil {

pacman.go

@@ -128,12 +128,12 @@ func (p *Pacman) Sync(ctx context.Context, args []string) error {
 
 // Install installs packages from the repositories.
 func (p *Pacman) Install(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "-S"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "--noconfirm"), "-S"), packages...)...)
 }
 
 // Remove removes packages.
 func (p *Pacman) Remove(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "-R"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "--noconfirm"), "-R"), packages...)...)
 }
 
 // Upgrade upgrades the named packages.
@@ -143,12 +143,12 @@ func (p *Pacman) Upgrade(ctx context.Context, args []string, packages ...string)
 
 // InstallFile installs a package from a local file.
 func (p *Pacman) InstallFile(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "-U"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "--noconfirm"), "-U"), packages...)...)
 }
 
 // UpgradeAll upgrades all packages with available updates.
 func (p *Pacman) UpgradeAll(ctx context.Context, args []string) error {
-	return p.exec(ctx, joinArgs(args, "-Syu")...)
+	return p.exec(ctx, joinArgs(p.confirmArgs(args, "--noconfirm"), "-Syu")...)
 }
 
 // Clean removes cached packages from the package cache.

yum.go

@@ -40,17 +40,17 @@ func (p *Yum) Sync(ctx context.Context, args []string) error {
 
 // Install installs packages from the repositories.
 func (p *Yum) Install(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "install"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "install"), packages...)...)
 }
 
 // Remove removes packages.
 func (p *Yum) Remove(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "remove"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "remove"), packages...)...)
 }
 
 // Upgrade upgrades the named packages.
 func (p *Yum) Upgrade(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "upgrade"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "-y"), "upgrade"), packages...)...)
 }
 
 // InstallFile installs a package from a local file.
@@ -60,7 +60,7 @@ func (p *Yum) InstallFile(ctx context.Context, args []string, packages ...string
 
 // UpgradeAll upgrades all packages with available updates.
 func (p *Yum) UpgradeAll(ctx context.Context, args []string) error {
-	return p.exec(ctx, joinArgs(args, "upgrade")...)
+	return p.exec(ctx, joinArgs(p.confirmArgs(args, "-y"), "upgrade")...)
 }
 
 // Clean removes cached repository metadata and packages.

zypper.go

@@ -43,17 +43,17 @@ func (p *Zypper) Sync(ctx context.Context, args []string) error {
 
 // Install installs packages from the repositories.
 func (p *Zypper) Install(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "install"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "--non-interactive"), "install"), packages...)...)
 }
 
 // Remove removes packages.
 func (p *Zypper) Remove(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "remove"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "--non-interactive"), "remove"), packages...)...)
 }
 
 // Upgrade upgrades the named packages.
 func (p *Zypper) Upgrade(ctx context.Context, args []string, packages ...string) error {
-	return p.exec(ctx, append(joinArgs(args, "update"), packages...)...)
+	return p.exec(ctx, append(joinArgs(p.confirmArgs(args, "--non-interactive"), "update"), packages...)...)
 }
 
 // InstallFile installs a package from a local file.
@@ -63,7 +63,7 @@ func (p *Zypper) InstallFile(ctx context.Context, args []string, packages ...str
 
 // UpgradeAll upgrades all packages with available updates.
 func (p *Zypper) UpgradeAll(ctx context.Context, args []string) error {
-	return p.exec(ctx, joinArgs(args, "update")...)
+	return p.exec(ctx, joinArgs(p.confirmArgs(args, "--non-interactive"), "update")...)
 }
 
 // Clean removes cached repository metadata and packages.