Better support for shell aliases (#4385)

- **PR Description**

In version 0.45.0 we started to use an interactive shell for running
shell commands (see #4159). The idea was that this allows users to use
their aliases and shell functions in lazygit without having to do any
additional configuration.

Unfortunately, this hasn't worked out well. For some users this resulted
in lazygit hanging in the background upon trying to return from the
shell command; we tried various fixes for this (see #4126, #4159, and
#4350), but some users still have this problem (e.g. #4320).

Also, starting an interactive shell can be a lot slower than starting a
non-interactive one, depending on how much happens in the `.bashrc` or
`.zshrc` file. For example, on my machine calling `zsh -ic true` takes
600ms, whereas `zsh -c true` takes less than 2ms. This is too high of a
price to pay for using shell aliases, especially when _all_ users have
to pay it, even those who don't care about using their aliases in
lazygit.

This PR reverts all commits related to interactive shells, and instead
introduces a different approach: we let users specify a shell aliases
file that will be sourced before running a command. The downside is that
it doesn't work transparently out of the box, but requires
configuration, and it may also require that users restructure their
shell startup file(s) if they currently only have a single big one. The
advantage is that only users who actually want to use aliases or
functions are affected, and that we can now use this mechanism not only
for shell commands, but also for custom commands and for calling the
editor (some users have asked for this in the past).

Author: stefanhaller

docs/Config.md

@@ -442,6 +442,10 @@ os:
   # See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#custom-command-for-copying-to-and-pasting-from-clipboard
   readFromClipboardCmd: ""
 
+  # A shell startup file containing shell aliases or shell functions. This will be sourced before running any shell commands, so that shell functions are available in the `:` command prompt or even in custom commands.
+  # See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#using-aliases-or-functions-in-shell-commands
+  shellFunctionsFile: ""
+
 # If true, don't display introductory popups upon opening Lazygit.
 disableStartupPopups: false
 
@@ -740,6 +744,21 @@ The `editInTerminal` option is used to decide whether lazygit needs to suspend i
 
 Contributions of new editor presets are welcome; see the `getPreset` function in [`editor_presets.go`](https://github.com/jesseduffield/lazygit/blob/master/pkg/config/editor_presets.go).
 
+## Using aliases or functions in shell commands
+
+Lazygit has a command prompt (`:`) for quickly executing shell commands without having to quit lazygit or switch to a different terminal. Most people find it convenient to have their usual shell aliases or shell functions available at this prompt. To achieve this, put your alias definitions in a separate shell startup file (which you source from your normal startup file, i.e. from `.bashrc` or `.zshrc`), and then tell lazygit about this file like so:
+
+```yml
+os:
+  shellFunctionsFile: ~/.my_aliases.sh
+```
+
+For many people it might work well enough to use their entire shell config file (`~/.bashrc` or `~/.zshrc`) as the `shellFunctionsFile`, but these config files typically do a lot more than defining aliases (e.g. initialize the completion system, start an ssh-agent, etc.) and this may unnecessarily delay execution of shell commands.
+
+When using zsh, aliases can't be used here, but functions can. It is easy to convert your existing aliases into functions, just change `alias l="ls -la"` to `l() ls -la`, for example. This way it will work as before both in the shell and in lazygit.
+
+Note that the shell aliases file is not only used when executing shell commands, but also for [custom commands](Custom_Command_Keybindings.md), and when opening a file in the editor.
+
 ## Overriding default config file location
 
 To override the default config directory, use `CONFIG_DIR="$HOME/.config/lazygit"`. This directory contains the config file in addition to some other files lazygit uses to keep track of state across sessions.

pkg/commands/git_cmd_obj_builder.go

@@ -34,12 +34,8 @@ func (self *gitCmdObjBuilder) New(args []string) oscommands.ICmdObj {
 	return self.innerBuilder.New(args).AddEnvVars(defaultEnvVar)
 }
 
-func (self *gitCmdObjBuilder) NewShell(cmdStr string) oscommands.ICmdObj {
-	return self.innerBuilder.NewShell(cmdStr).AddEnvVars(defaultEnvVar)
-}
-
-func (self *gitCmdObjBuilder) NewInteractiveShell(cmdStr string) oscommands.ICmdObj {
-	return self.innerBuilder.NewInteractiveShell(cmdStr).AddEnvVars(defaultEnvVar)
+func (self *gitCmdObjBuilder) NewShell(cmdStr string, shellFunctionsFile string) oscommands.ICmdObj {
+	return self.innerBuilder.NewShell(cmdStr, shellFunctionsFile).AddEnvVars(defaultEnvVar)
 }
 
 func (self *gitCmdObjBuilder) Quote(str string) string {

pkg/commands/oscommands/cmd_obj_builder.go

@@ -13,9 +13,9 @@ type ICmdObjBuilder interface {
 	// NewFromArgs takes a slice of strings like []string{"git", "commit"} and returns a new command object.
 	New(args []string) ICmdObj
 	// NewShell takes a string like `git commit` and returns an executable shell command for it e.g. `sh -c 'git commit'`
-	NewShell(commandStr string) ICmdObj
-	// Like NewShell, but uses the user's shell rather than "bash", and passes -i to it
-	NewInteractiveShell(commandStr string) ICmdObj
+	// shellFunctionsFile is an optional file path that will be sourced before executing the command. Callers should pass
+	// the value of UserConfig.OS.ShellFunctionsFile.
+	NewShell(commandStr string, shellFunctionsFile string) ICmdObj
 	// Quote wraps a string in quotes with any necessary escaping applied. The reason for bundling this up with the other methods in this interface is that we basically always need to make use of this when creating new command objects.
 	Quote(str string) string
 }
@@ -44,20 +44,16 @@ func (self *CmdObjBuilder) NewWithEnviron(args []string, env []string) ICmdObj {
 	}
 }
 
-func (self *CmdObjBuilder) NewShell(commandStr string) ICmdObj {
+func (self *CmdObjBuilder) NewShell(commandStr string, shellFunctionsFile string) ICmdObj {
+	if len(shellFunctionsFile) > 0 {
+		commandStr = fmt.Sprintf("%ssource %s\n%s", self.platform.PrefixForShellFunctionsFile, shellFunctionsFile, commandStr)
+	}
 	quotedCommand := self.quotedCommandString(commandStr)
 	cmdArgs := str.ToArgv(fmt.Sprintf("%s %s %s", self.platform.Shell, self.platform.ShellArg, quotedCommand))
 
 	return self.New(cmdArgs)
 }
 
-func (self *CmdObjBuilder) NewInteractiveShell(commandStr string) ICmdObj {
-	quotedCommand := self.quotedCommandString(commandStr + self.platform.InteractiveShellExit)
-	cmdArgs := str.ToArgv(fmt.Sprintf("%s %s %s %s", self.platform.InteractiveShell, self.platform.InteractiveShellArg, self.platform.ShellArg, quotedCommand))
-
-	return self.New(cmdArgs)
-}
-
 func (self *CmdObjBuilder) quotedCommandString(commandStr string) string {
 	// Windows does not seem to like quotes around the command
 	if self.platform.OS == "windows" {

pkg/commands/oscommands/dummies.go

@@ -51,14 +51,11 @@ func NewDummyCmdObjBuilder(runner ICmdObjRunner) *CmdObjBuilder {
 }
 
 var dummyPlatform = &Platform{
-	OS:                   "darwin",
-	Shell:                "bash",
-	InteractiveShell:     "bash",
-	ShellArg:             "-c",
-	InteractiveShellArg:  "-i",
-	InteractiveShellExit: "; exit $?",
-	OpenCommand:          "open {{filename}}",
-	OpenLinkCommand:      "open {{link}}",
+	OS:              "darwin",
+	Shell:           "bash",
+	ShellArg:        "-c",
+	OpenCommand:     "open {{filename}}",
+	OpenLinkCommand: "open {{link}}",
 }
 
 func NewDummyOSCommandWithRunner(runner *FakeCmdObjRunner) *OSCommand {

pkg/commands/oscommands/os.go

@@ -35,14 +35,12 @@ type OSCommand struct {
 
 // Platform stores the os state
 type Platform struct {
-	OS                   string
-	Shell                string
-	InteractiveShell     string
-	ShellArg             string
-	InteractiveShellArg  string
-	InteractiveShellExit string
-	OpenCommand          string
-	OpenLinkCommand      string
+	OS                          string
+	Shell                       string
+	ShellArg                    string
+	PrefixForShellFunctionsFile string
+	OpenCommand                 string
+	OpenLinkCommand             string
 }
 
 // NewOSCommand os command runner
@@ -93,7 +91,7 @@ func (c *OSCommand) OpenFile(filename string) error {
 		"filename": c.Quote(filename),
 	}
 	command := utils.ResolvePlaceholderString(commandTemplate, templateValues)
-	return c.Cmd.NewShell(command).Run()
+	return c.Cmd.NewShell(command, c.UserConfig().OS.ShellFunctionsFile).Run()
 }
 
 func (c *OSCommand) OpenLink(link string) error {
@@ -110,7 +108,7 @@ func (c *OSCommand) OpenLink(link string) error {
 	}
 
 	command := utils.ResolvePlaceholderString(commandTemplate, templateValues)
-	return c.Cmd.NewShell(command).Run()
+	return c.Cmd.NewShell(command, c.UserConfig().OS.ShellFunctionsFile).Run()
 }
 
 // Quote wraps a message in platform-specific quotation marks
@@ -299,7 +297,7 @@ func (c *OSCommand) CopyToClipboard(str string) error {
 		cmdStr := utils.ResolvePlaceholderString(c.UserConfig().OS.CopyToClipboardCmd, map[string]string{
 			"text": c.Cmd.Quote(str),
 		})
-		return c.Cmd.NewShell(cmdStr).Run()
+		return c.Cmd.NewShell(cmdStr, c.UserConfig().OS.ShellFunctionsFile).Run()
 	}
 
 	return clipboard.WriteAll(str)
@@ -310,7 +308,7 @@ func (c *OSCommand) PasteFromClipboard() (string, error) {
 	var err error
 	if c.UserConfig().OS.CopyToClipboardCmd != "" {
 		cmdStr := c.UserConfig().OS.ReadFromClipboardCmd
-		s, err = c.Cmd.NewShell(cmdStr).RunWithOutput()
+		s, err = c.Cmd.NewShell(cmdStr, c.UserConfig().OS.ShellFunctionsFile).RunWithOutput()
 	} else {
 		s, err = clipboard.ReadAll()
 	}
@@ -360,5 +358,5 @@ func (c *OSCommand) UpdateWindowTitle() error {
 		return getWdErr
 	}
 	argString := fmt.Sprint("title ", filepath.Base(path), " - Lazygit")
-	return c.Cmd.NewShell(argString).Run()
+	return c.Cmd.NewShell(argString, c.UserConfig().OS.ShellFunctionsFile).Run()
 }

pkg/commands/oscommands/os_default_platform.go

@@ -12,27 +12,18 @@ import (
 func GetPlatform() *Platform {
 	shell := getUserShell()
 
-	interactiveShell := shell
-	interactiveShellArg := "-i"
-	interactiveShellExit := "; exit $?"
-
-	if strings.HasSuffix(shell, "fish") {
-		interactiveShellExit = "; exit $status"
-	} else if !(strings.HasSuffix(shell, "bash") || strings.HasSuffix(shell, "zsh")) {
-		interactiveShell = "bash"
-		interactiveShellArg = ""
-		interactiveShellExit = ""
+	prefixForShellFunctionsFile := ""
+	if strings.HasSuffix(shell, "bash") {
+		prefixForShellFunctionsFile = "shopt -s expand_aliases\n"
 	}
 
 	return &Platform{
-		OS:                   runtime.GOOS,
-		Shell:                "bash",
-		InteractiveShell:     interactiveShell,
-		ShellArg:             "-c",
-		InteractiveShellArg:  interactiveShellArg,
-		InteractiveShellExit: interactiveShellExit,
-		OpenCommand:          "open {{filename}}",
-		OpenLinkCommand:      "open {{link}}",
+		OS:                          runtime.GOOS,
+		Shell:                       shell,
+		ShellArg:                    "-c",
+		PrefixForShellFunctionsFile: prefixForShellFunctionsFile,
+		OpenCommand:                 "open {{filename}}",
+		OpenLinkCommand:             "open {{link}}",
 	}
 }
 

pkg/commands/oscommands/os_windows.go

@@ -2,11 +2,8 @@ package oscommands
 
 func GetPlatform() *Platform {
 	return &Platform{
-		OS:                   "windows",
-		Shell:                "cmd",
-		InteractiveShell:     "cmd",
-		ShellArg:             "/c",
-		InteractiveShellArg:  "",
-		InteractiveShellExit: "",
+		OS:       "windows",
+		Shell:    "cmd",
+		ShellArg: "/c",
 	}
 }

pkg/config/user_config.go

@@ -581,6 +581,18 @@ type OSConfig struct {
 	// Command for opening a link. Should contain "{{link}}".
 	OpenLink string `yaml:"openLink,omitempty"`
 
+	// CopyToClipboardCmd is the command for copying to clipboard.
+	// See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#custom-command-for-copying-to-and-pasting-from-clipboard
+	CopyToClipboardCmd string `yaml:"copyToClipboardCmd,omitempty"`
+
+	// ReadFromClipboardCmd is the command for reading the clipboard.
+	// See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#custom-command-for-copying-to-and-pasting-from-clipboard
+	ReadFromClipboardCmd string `yaml:"readFromClipboardCmd,omitempty"`
+
+	// A shell startup file containing shell aliases or shell functions. This will be sourced before running any shell commands, so that shell functions are available in the `:` command prompt or even in custom commands.
+	// See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#using-aliases-or-functions-in-shell-commands
+	ShellFunctionsFile string `yaml:"shellFunctionsFile"`
+
 	// --------
 
 	// The following configs are all deprecated and kept for backward
@@ -603,14 +615,6 @@ type OSConfig struct {
 	// OpenLinkCommand is the command for opening a link
 	// Deprecated: use OpenLink instead.
 	OpenLinkCommand string `yaml:"openLinkCommand,omitempty" jsonschema:"deprecated"`
-
-	// CopyToClipboardCmd is the command for copying to clipboard.
-	// See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#custom-command-for-copying-to-and-pasting-from-clipboard
-	CopyToClipboardCmd string `yaml:"copyToClipboardCmd,omitempty"`
-
-	// ReadFromClipboardCmd is the command for reading the clipboard.
-	// See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#custom-command-for-copying-to-and-pasting-from-clipboard
-	ReadFromClipboardCmd string `yaml:"readFromClipboardCmd,omitempty"`
 }
 
 type CustomCommandAfterHook struct {

pkg/gui/controllers/helpers/files_helper.go

@@ -71,11 +71,11 @@ func (self *FilesHelper) OpenDirInEditor(path string) error {
 func (self *FilesHelper) callEditor(cmdStr string, suspend bool) error {
 	if suspend {
 		return self.c.RunSubprocessAndRefresh(
-			self.c.OS().Cmd.NewShell(cmdStr),
+			self.c.OS().Cmd.NewShell(cmdStr, self.c.UserConfig().OS.ShellFunctionsFile),
 		)
 	}
 
-	return self.c.OS().Cmd.NewShell(cmdStr).Run()
+	return self.c.OS().Cmd.NewShell(cmdStr, self.c.UserConfig().OS.ShellFunctionsFile).Run()
 }
 
 func (self *FilesHelper) OpenFile(filename string) error {

pkg/gui/controllers/shell_command_action.go

@@ -31,7 +31,7 @@ func (self *ShellCommandAction) Call() error {
 
 			self.c.LogAction(self.c.Tr.Actions.CustomCommand)
 			return self.c.RunSubprocessAndRefresh(
-				self.c.OS().Cmd.NewInteractiveShell(command),
+				self.c.OS().Cmd.NewShell(command, self.c.UserConfig().OS.ShellFunctionsFile),
 			)
 		},
 		HandleDeleteSuggestion: func(index int) error {