From a7bed6146156ce1548446700d2189e0caf6c8a75 Mon Sep 17 00:00:00 2001
From: Koichi Murase <myoga.murase@gmail.com>
Date: Wed, 10 Jan 2024 23:11:12 +0900
Subject: fix(bash): work around bash < 4 and introduce initialization guards
 (#1533)

* fix(bash): add a guard for interactive shells

* fix(bash): add a guard for the Bash version

* fix(bash): localize READLINE_LINE in bash < 4

In bash < 4, the variables READLINE_LINE and READLINE_POINT are not
supported for the shell commands called by `bind -x`.  Even if it is
not supported, atuin works in not a bad way.  However, this sometimes
causes a strange behavior by the remaining values of READLINE_LINE set
in the previous calls of __atuin_history.  In bash < 4, we can
consistently use an empty string instead of $READLINE_LINE, and the
changes to READLINE_LINE and READLINE_POINT should be localized within
the function.

* fix(bash): add guard for double initialization

In bash, it is customary to reload the settings by sourcing `.bashrc`
again after modifying it.  In such a case, `eval "$(atuin init bash)"`
is executed again.  This registers duplicate hooks to
`preexec_functions` and `precmd_functions`.  To prevent this in this
patch, we introduce an include guard, so that the initialization is
not performed more than once.
---
 README.md                  |  4 ++++
 atuin/src/shell/atuin.bash | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/README.md b/README.md
index 2aa554da..1b893f49 100644
--- a/README.md
+++ b/README.md
@@ -265,6 +265,8 @@ antigen bundle atuinsh/atuin@main
 
 ### bash
 
+Atuin works in `bash >= 3.1`, but we recommend to use Atuin with the recent versions of `bash >= 5`.
+
 #### [ble.sh](https://github.com/akinomyoga/ble.sh)
 
 Atuin works best in bash when using [ble.sh](https://github.com/akinomyoga/ble.sh) >= 0.4.
@@ -298,6 +300,8 @@ echo 'eval "$(atuin init bash)"' >> ~/.bashrc
 
 bash-preexec currently has an issue where it will stop honoring `ignorespace`. While Atuin will ignore commands prefixed with whitespace, they may still end up in your bash history. Please check your configuration! All other shells do not have this issue.
 
+To use Atuin in `bash < 4` with bash-preexec, the option `enter_accept` needs to be turned on (which is so by default).
+
 ### fish
 
 Add
diff --git a/atuin/src/shell/atuin.bash b/atuin/src/shell/atuin.bash
index 3814193e..933416e6 100644
--- a/atuin/src/shell/atuin.bash
+++ b/atuin/src/shell/atuin.bash
@@ -1,3 +1,16 @@
+# Include guard
+[[ ${__atuin_initialized-} == true ]] && return 0
+__atuin_initialized=true
+
+# Enable only in interactive shells
+[[ $- == *i* ]] || return 0
+
+# Require bash >= 3.1
+if ((BASH_VERSINFO[0] < 3 || BASH_VERSINFO[0] == 3 && BASH_VERSINFO[1] < 1)); then
+    [[ -t 2 ]] && printf 'atuin: requires bash >= 3.1 for the integration.\n' >&2
+    return 0
+fi
+
 ATUIN_SESSION=$(atuin uuid)
 ATUIN_STTY=$(stty -g)
 export ATUIN_SESSION
@@ -154,6 +167,12 @@ __atuin_history() {
         fi
     fi
 
+    # READLINE_LINE and READLINE_POINT are only supported by bash >= 4.0 or
+    # ble.sh.  When it is not supported, we localize them to suppress strange
+    # behaviors.
+    [[ ${BLE_ATTACHED-} ]] || ((BASH_VERSINFO[0] >= 4)) ||
+        local READLINE_LINE="" READLINE_POINT=0
+
     local __atuin_output
     __atuin_output=$(ATUIN_SHELL_BASH=t ATUIN_LOG=error atuin search "$@" -i -- "$READLINE_LINE" 3>&1 1>&2 2>&3)
 
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