Validate the context names in the "context" field of custom commands (#5989)

If a custom command's "context" field contains a context name that
doesn't exist, lazygit panics when building the keybindings. This could
happen either because of a typo, or because a context is removed or
renamed in a later version. Prevent the panic by validating those names
at config load time, and rejecting the config as invalid there, like we
do for other config errors.

pkg/config/user_config_validation.go

@@ -191,6 +191,51 @@ func validateCustomCommandKey(key Keybinding) error {
 	return nil
 }
 
+// ValidCustomCommandContexts lists the names a custom command's 'context' may
+// use. It mirrors context.AllContextKeys in the gui package, which this package
+// can't import; a test over there keeps the two in sync.
+var ValidCustomCommandContexts = []string{
+	"global",
+	"status",
+	"files",
+	"localBranches",
+	"remotes",
+	"worktrees",
+	"remoteBranches",
+	"tags",
+	"commits",
+	"reflogCommits",
+	"subCommits",
+	"commitFiles",
+	"stash",
+	"normal",
+	"normalSecondary",
+	"staging",
+	"stagingSecondary",
+	"patchBuilding",
+	"patchBuildingSecondary",
+	"mergeConflicts",
+	"menu",
+	"confirmation",
+	"prompt",
+	"search",
+	"commitMessage",
+	"submodules",
+	"suggestions",
+	"cmdLog",
+}
+
+func validateCustomCommandContext(context string) error {
+	for _, name := range strings.Split(context, ",") {
+		name = strings.TrimSpace(name)
+		if !slices.Contains(ValidCustomCommandContexts, name) {
+			return fmt.Errorf("Unknown context '%s' for custom command. Allowed values: %s",
+				name, strings.Join(ValidCustomCommandContexts, ", "))
+		}
+	}
+	return nil
+}
+
 func validateCustomCommands(customCommands []CustomCommand) error {
 	for _, customCommand := range customCommands {
 		if err := validateCustomCommandKey(customCommand.Key); err != nil {
@@ -216,6 +261,15 @@ func validateCustomCommands(customCommands []CustomCommand) error {
 				return err
 			}
 		} else {
+			// A command in a menu may leave the context out, in which case it is
+			// offered whatever is focused; a top-level one may not, but that is
+			// only noticed when the keybindings are built.
+			if customCommand.Context != "" {
+				if err := validateCustomCommandContext(customCommand.Context); err != nil {
+					return err
+				}
+			}
+
 			for _, prompt := range customCommand.Prompts {
 				if err := validateCustomCommandPrompt(prompt); err != nil {
 					return err

pkg/config/user_config_validation_test.go

@@ -225,6 +225,43 @@ func TestUserConfigValidate_enums(t *testing.T) {
 				{value: "invalid_value", valid: false},
 			},
 		},
+		{
+			name: "Custom command context",
+			setup: func(config *UserConfig, value string) {
+				config.CustomCommands = []CustomCommand{
+					{
+						Context: value,
+					},
+				}
+			},
+			testCases: []testCase{
+				{value: "", valid: true},
+				{value: "global", valid: true},
+				{value: "commits", valid: true},
+				{value: "commits, subCommits", valid: true},
+				{value: "commits,subCommits", valid: true},
+				{value: "invalid_value", valid: false},
+				{value: "commits, invalid_value", valid: false},
+			},
+		},
+		{
+			name: "Custom command context in a sub menu",
+			setup: func(config *UserConfig, value string) {
+				config.CustomCommands = []CustomCommand{
+					{
+						Key: Keybinding{"X"},
+						CommandMenu: []CustomCommand{
+							{Key: Keybinding{"1"}, Command: "echo 'hello'", Context: value},
+						},
+					},
+				}
+			},
+			testCases: []testCase{
+				{value: "", valid: true},
+				{value: "commits", valid: true},
+				{value: "invalid_value", valid: false},
+			},
+		},
 		{
 			name: "Custom command sub menu",
 			setup: func(config *UserConfig, _ string) {

pkg/gui/context/context_test.go

@@ -0,0 +1,22 @@
+package context
+
+import (
+	"testing"
+
+	"github.com/jesseduffield/lazygit/pkg/config"
+	"github.com/jesseduffield/lazygit/pkg/gui/types"
+	"github.com/samber/lo"
+	"github.com/stretchr/testify/assert"
+)
+
+// The config package validates a custom command's context against its own copy of
+// these names, being unable to import this package. A name in one list but not the
+// other would be either a context that validation rejects although you can bind to
+// it, or one it accepts although binding to it exits lazygit.
+func TestValidCustomCommandContextsMatchesAllContextKeys(t *testing.T) {
+	keys := lo.Map(AllContextKeys, func(key types.ContextKey, _ int) string {
+		return string(key)
+	})
+
+	assert.Equal(t, keys, config.ValidCustomCommandContexts)
+}