v0.4.0

Close #25

CHANGELOG.md

@@ -2,6 +2,30 @@
 
 ### master
 
+### v0.4.0, 2014-08-29
+- change plugin name to `tmux-resurrect`. Change all the variable names.
+
+### v0.3.0, 2014-08-29
+- bugfix: when top is running the pane `$PWD` can't be saved. This was causing
+  issues during the restore and is now fixed.
+- restoring sessions multiple times messes up the whole environment - new panes
+  are all around. This is now fixed - pane restorations are now idempotent.
+- if pane exists from before session restore - do not restore the process within
+  it. This makes the restoration process even more idempotent.
+- more panes within a window can now be restored
+- restore window zoom state
+
+### v0.2.0, 2014-08-29
+- bugfix: with vim 'session' strategy, if the session file does not exist - make
+  sure vim does not contain `-S` flag
+- enable restoring programs with arguments (e.g. "rails console") and also
+  processes that contain program name
+- improve `irb` restore strategy
+
+### v0.1.0, 2014-08-28
+- refactor checking if saved tmux session exists
+- spinner while tmux sessions are restored
+
 ### v0.0.5, 2014-08-28
 - restore pane processes
 - user option for disabling pane process restoring

CONTRIBUTING.md

@@ -0,0 +1,12 @@
+### Contributing
+
+Code contributions are welcome!
+
+### Reporting a bug
+
+If you find a bug please report it in the issues. When reporting a bug please
+attach:
+- a file symlinked to `~/.tmux/resurrect/last`.
+- your `.tmux.conf`
+- if you're getting an error paste it to a [gist](https://gist.github.com/) and
+  link it in the issue

README.md

@@ -1,17 +1,18 @@
-# Tmux Session Saver
+# Tmux Resurrect
 
-Persists `tmux` environment across system restarts.
+Restore `tmux` environment after a system restart.
 
-Tmux is great, except when you have to restart your computer. You loose all the
+Tmux is great, except when you have to restart the computer. You loose all the
 running programs, working directories, pane layouts etc.
 There are helpful management tools out there, but they require initial
 configuration and continuous updates as your workflow evolves or you start new
 projects.
 
-Enter `tmux-session-saver`: tmux persistence without configuration so there are
+`tmux-resurrect` saves all the little details from tmux environment so it
-no interruptions in your workflow.
+can be completely restored after a system restart. No configuration is required.
+You should feel like you never quit tmux.
 
-It will even (optionally) [restore vim sessions](#restoring-vim-sessions)!
+It even (optionally) [restores vim sessions](#restoring-vim-sessions)!
 
 ### Key bindings
 
@@ -28,8 +29,10 @@ This plugin goes to great lengths to save and restore all the details from your
 - **exact pane layouts** within windows
 - active and alternative session
 - active and alternative window for each session
+- windows with focus
 - active pane for each window
-- programs running within a pane! More details in the [configuration section](#configuration).
+- programs running within a pane! More details in the
+  [configuration section](#configuration).
 - restoring vim sessions (optional). More details in
   [restoring vim sessions](#restoring-vim-sessions).
 
@@ -41,7 +44,7 @@ Add plugin to the list of TPM plugins in `.tmux.conf`:
 
     set -g @tpm_plugins "           \
       tmux-plugins/tpm              \
-      tmux-plugins/tmux-session-saver  \
+      tmux-plugins/tmux-resurrect   \
     "
 
 Hit `prefix + I` to fetch the plugin and source it. You should now be able to
@@ -51,11 +54,11 @@ use the plugin.
 
 Clone the repo:
 
-    $ git clone https://github.com/tmux-plugins/tmux-session-saver ~/clone/path
+    $ git clone https://github.com/tmux-plugins/tmux-resurrect ~/clone/path
 
 Add this line to the bottom of `.tmux.conf`:
 
-    run-shell ~/clone/path/session_saver.tmux
+    run-shell ~/clone/path/resurrect.tmux
 
 Reload TMUX environment:
 
@@ -66,38 +69,46 @@ You should now be able to use the plugin.
 
 ### Configuration
 
-By default, only a conservative list of programs is restored:
+Configuration is not required - but it enables extra features.
-`vim emacs man less more tail top htop irssi`.
+
+Only a conservative list of programs is restored by default:<br/>
+`vi vim emacs man less more tail top htop irssi irb pry "~rails console"`.
 Open a github issue if you think some other program should be on the default list.
 
-- Restore additional programs by putting the following in `.tmux.conf`:
+- Restore additional programs with the setting in `.tmux.conf`:
 
-        set -g @session-saver-processes 'ssh telnet myprogram'
+        set -g @resurrect-processes 'ssh psql mysql sqlite3'
+
+- Programs with arguments should be double quoted:
+
+        set -g @resurrect-processes 'some_program "git log"'
+
+- Start with tilde to restore a program whose process contains target name:
+
+        set -g @resurrect-processes 'some_program "~rails server"'
 
 - Don't restore any programs:
 
-        set -g @session-saver-processes 'false'
+        set -g @resurrect-processes 'false'
 
 - Restore **all** programs (be careful with this!):
 
-        set -g @session-saver-processes ':all:'
+        set -g @resurrect-processes ':all:'
 
 #### Restoring vim sessions
 
-- save vim sessions - I recommend [tpope/vim-obsession](tpope/vim-obsession)
+- save vim sessions. I recommend [tpope/vim-obsession](tpope/vim-obsession).
 - in `.tmux.conf`:
 
-        set -g @session-saver-strategy-vim "session"
+        set -g @resurrect-strategy-vim "session"
 
-`tmux-session-saver` will now restore vim sessions if `Sessions.vim` file is
+`tmux-resurrect` will now restore vim sessions if `Sessions.vim` file is
 present.
 
 ### Reporting bugs and contributing
 
-Code contributions are welcome!
+Both contributing and bug reports are welcome. Please check out
-
+[contributing guidelines](CONTRIBUTING.md).
-If you find a bug please report it in the issues. When reporting a bug please
-attach a file symlinked to `~/.tmux/sessions/last`.
 
 ### Credits
 

resurrect.tmux

@@ -2,19 +2,14 @@
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
+source "$CURRENT_DIR/scripts/variables.sh"
 source "$CURRENT_DIR/scripts/helpers.sh"
 
-default_save_key="M-s"
-save_option="@session-saver-save"
-
-default_restore_key="M-r"
-restore_option="@session-saver-restore"
-
 set_save_bindings() {
 	local key_bindings=$(get_tmux_option "$save_option" "$default_save_key")
 	local key
 	for key in $key_bindings; do
-		tmux bind-key "$key" run-shell "$CURRENT_DIR/scripts/session_saver.sh"
+		tmux bind-key "$key" run-shell "$CURRENT_DIR/scripts/save.sh"
 	done
 }
 
@@ -22,12 +17,17 @@ set_restore_bindings() {
 	local key_bindings=$(get_tmux_option "$restore_option" "$default_restore_key")
 	local key
 	for key in $key_bindings; do
-		tmux bind-key "$key" run-shell "$CURRENT_DIR/scripts/session_restorer.sh"
+		tmux bind-key "$key" run-shell "$CURRENT_DIR/scripts/restore.sh"
 	done
 }
 
+set_default_strategies() {
+	tmux set-option -g "${restore_process_strategy_option}irb" "default_strategy"
+}
+
 main() {
 	set_save_bindings
 	set_restore_bindings
+	set_default_strategies
 }
 main

scripts/helpers.sh

@@ -1,6 +1,5 @@
-# configurable constants
+default_resurrect_dir="$HOME/.tmux/resurrect"
-default_sessions_dir="$HOME/.tmux/sessions"
+resurrect_dir_option="@resurrect-dir"
-sessions_dir_option="@session-saver-dir"
 
 SUPPORTED_VERSION="1.9"
 
@@ -46,17 +45,21 @@ supported_tmux_version_ok() {
 	$CURRENT_DIR/check_tmux_version.sh "$SUPPORTED_VERSION"
 }
 
+remove_first_char() {
+	echo "$1" | cut -c2-
+}
+
 # path helpers
 
-sessions_dir() {
+resurrect_dir() {
-	echo $(get_tmux_option "$sessions_dir_option" "$default_sessions_dir")
+	echo $(get_tmux_option "$resurrect_dir_option" "$default_resurrect_dir")
 }
 
-session_path() {
+resurrect_file_path() {
 	local timestamp="$(date +"%Y-%m-%dT%H:%M:%S")"
-	echo "$(sessions_dir)/tmux_session_${timestamp}.txt"
+	echo "$(resurrect_dir)/tmux_resurrect_${timestamp}.txt"
 }
 
-last_session_path() {
+last_resurrect_file() {
-	echo "$(sessions_dir)/last"
+	echo "$(resurrect_dir)/last"
 }

scripts/process_restore_helpers.sh

@@ -1,20 +1,3 @@
-# default processes that are restored
-default_proc_list_option="@session-saver-default-processes"
-default_proc_list="vim emacs man less more tail top htop irssi"
-
-# User defined processes that are restored
-#  'false' - nothing is restored
-#  ':all:' - all processes are restored
-#
-# user defined list of programs that are restored:
-#  'my_program foo another_program'
-restore_processes_option="@session-saver-processes"
-restore_processes=""
-
-# Defines part of the user variable. Example usage:
-#   set -g @session-saver-strategy-vim "session"
-restore_process_strategy_option="@session-saver-strategy-"
-
 restore_pane_processes_enabled() {
 	local restore_processes="$(get_tmux_option "$restore_processes_option" "$restore_processes")"
 	if [ "$restore_processes" == "false" ]; then
@@ -30,7 +13,7 @@ restore_pane_process() {
 	local window_number="$3"
 	local pane_index="$4"
 	local dir="$5"
-	if _process_should_be_restored "$pane_full_command"; then
+	if _process_should_be_restored "$pane_full_command" "$session_name" "$window_number" "$pane_index"; then
 		tmux switch-client -t "${session_name}:${window_number}"
 		tmux select-pane -t "$pane_index"
 
@@ -38,8 +21,6 @@ restore_pane_process() {
 			local strategy_file="$(_get_strategy_file "$pane_full_command")"
 			local strategy_command="$($strategy_file "$pane_full_command" "$dir")"
 			tmux send-keys "$strategy_command" "C-m"
-			# tmux send-keys "Strategy! $pane_full_command $strategy_file"
-			# tmux send-keys "Strategy! $strategy_command"
 		else
 			# just invoke the command
 			tmux send-keys "$pane_full_command" "C-m"
@@ -51,7 +32,14 @@ restore_pane_process() {
 
 _process_should_be_restored() {
 	local pane_full_command="$1"
-	if _restore_all_processes; then
+	local session_name="$2"
+	local window_number="$3"
+	local pane_index="$4"
+	if is_pane_registered_as_existing "$session_name" "$window_number" "$pane_index"; then
+		# Scenario where pane existed before restoration, so we're not
+		# restoring the proces either.
+		return 1
+	elif _restore_all_processes; then
 		return 0
 	elif _process_on_the_restore_list "$pane_full_command"; then
 		return 0
@@ -71,12 +59,22 @@ _restore_all_processes() {
 
 _process_on_the_restore_list() {
 	local pane_full_command="$1"
-	local restore_list="$(_restore_list)"
+	# TODO: make this work without eval
+	eval set $(_restore_list)
 	local proc
-	for proc in $restore_list; do
+	for proc in "$@"; do
-		if [[ "$pane_full_command" =~ (^$proc) ]]; then
+		if _proc_starts_with_tildae "$proc"; then
+			proc="$(remove_first_char "$proc")"
+			# regex matching the command makes sure `$proc` string is somewhere the command string
+			if [[ "$pane_full_command" =~ ($proc) ]]; then
 				return 0
 			fi
+		else
+			# regex matching the command makes sure process is a "word"
+			if [[ "$pane_full_command" =~ (^${proc} ) ]] || [[ "$pane_full_command" =~ (^${proc}$) ]]; then
+				return 0
+			fi
+		fi
 	done
 	return 1
 }
@@ -92,6 +90,10 @@ _restore_list() {
 	fi
 }
 
+_proc_starts_with_tildae() {
+	[[ "$1" =~ (^~) ]]
+}
+
 _strategy_exists() {
 	local pane_full_command="$1"
 	local strategy="$(_get_command_strategy "$pane_full_command")"

scripts/restore.sh

@@ -2,8 +2,16 @@
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
+source "$CURRENT_DIR/variables.sh"
 source "$CURRENT_DIR/helpers.sh"
 source "$CURRENT_DIR/process_restore_helpers.sh"
+source "$CURRENT_DIR/spinner_helpers.sh"
+
+# Global variable.
+# Used during the restore: if a pane already exists from before, it is
+# saved in the array in this variable. Later, process running in existing pane
+# is also not restored. That makes the restoration process more idempotent.
+EXISTING_PANES_VAR=""
 
 is_line_type() {
 	local line_type="$1"
@@ -13,13 +21,38 @@ is_line_type() {
 }
 
 check_saved_session_exists() {
-	local saved_session="$(last_session_path)"
+	local resurrect_file="$(last_resurrect_file)"
-	if [ ! -f $saved_session ]; then
+	if [ ! -f $resurrect_file ]; then
-		display_message "Saved session not found!"
+		display_message "Tmux resurrect file not found!"
-		exit
+		return 1
 	fi
 }
 
+pane_exists() {
+	local session_name="$1"
+	local window_number="$2"
+	local pane_index="$3"
+	tmux list-panes -t "${session_name}:${window_number}" -F "#{pane_index}" 2>/dev/null |
+		\grep -q "^$pane_index$"
+}
+
+register_existing_pane() {
+	local session_name="$1"
+	local window_number="$2"
+	local pane_index="$3"
+	local pane_custom_id="${session_name}:${window_number}:${pane_index}"
+	local delimiter=$'\t'
+	EXISTING_PANES_VAR="${EXISTING_PANES_VAR}${delimiter}${pane_custom_id}"
+}
+
+is_pane_registered_as_existing() {
+	local session_name="$1"
+	local window_number="$2"
+	local pane_index="$3"
+	local pane_custom_id="${session_name}:${window_number}:${pane_index}"
+	[[ "$EXISTING_PANES_VAR" =~ "$pane_custom_id" ]]
+}
+
 window_exists() {
 	local session_name="$1"
 	local window_number="$2"
@@ -40,10 +73,6 @@ tmux_socket() {
 	echo $TMUX | cut -d',' -f1
 }
 
-remove_first_char() {
-	echo "$1" | cut -c2-
-}
-
 new_window() {
 	local session_name="$1"
 	local window_number="$2"
@@ -70,23 +99,28 @@ new_pane() {
 	local window_number="$2"
 	local window_name="$3"
 	local dir="$4"
-	tmux split-window -t "${session_name}:${window_number}" -c "$dir"
+	tmux split-window -t "${session_name}:${window_number}" -c "$dir" -h
+	tmux resize-pane  -t "${session_name}:${window_number}" -L "999"
 }
 
 restore_pane() {
 	local pane="$1"
-	echo "$pane" |
 	while IFS=$'\t' read line_type session_name window_number window_name window_active window_flags pane_index dir pane_active pane_command pane_full_command; do
+		dir="$(remove_first_char "$dir")"
 		window_name="$(remove_first_char "$window_name")"
 		pane_full_command="$(remove_first_char "$pane_full_command")"
-		if window_exists "$session_name" "$window_number"; then
+		if pane_exists "$session_name" "$window_number" "$pane_index"; then
+			# Pane exists, no need to create it!
+			# Pane existence is registered. Later, it's process also isn't restored.
+			register_existing_pane "$session_name" "$window_number" "$pane_index"
+		elif window_exists "$session_name" "$window_number"; then
 			new_pane "$session_name" "$window_number" "$window_name" "$dir"
 		elif session_exists "$session_name"; then
 			new_window "$session_name" "$window_number" "$window_name" "$dir"
 		else
 			new_session "$session_name" "$window_number" "$window_name" "$dir"
 		fi
-	done
+	done < <(echo "$pane")
 }
 
 restore_state() {
@@ -98,19 +132,20 @@ restore_state() {
 	done
 }
 
-restore_all_sessions() {
+restore_all_panes() {
 	while read line; do
 		if is_line_type "pane" "$line"; then
 			restore_pane "$line"
 		fi
-	done < $(last_session_path)
+	done < $(last_resurrect_file)
 }
 
 restore_all_pane_processes() {
 	if restore_pane_processes_enabled; then
 		local pane_full_command
-		awk 'BEGIN { FS="\t"; OFS="\t" } /^pane/ && $11 !~ "^:$" { print $2, $3, $7, $8, $11; }' $(last_session_path) |
+		awk 'BEGIN { FS="\t"; OFS="\t" } /^pane/ && $11 !~ "^:$" { print $2, $3, $7, $8, $11; }' $(last_resurrect_file) |
 			while IFS=$'\t' read session_name window_number pane_index dir pane_full_command; do
+				dir="$(remove_first_char "$dir")"
 				pane_full_command="$(remove_first_char "$pane_full_command")"
 				restore_pane_process "$pane_full_command" "$session_name" "$window_number" "$pane_index" "$dir"
 			done
@@ -118,22 +153,29 @@ restore_all_pane_processes() {
 }
 
 restore_pane_layout_for_each_window() {
-	\grep '^window' $(last_session_path) |
+	\grep '^window' $(last_resurrect_file) |
 		while IFS=$'\t' read line_type session_name window_number window_active window_flags window_layout; do
 			tmux select-layout -t "${session_name}:${window_number}" "$window_layout"
 		done
 }
 
 restore_active_pane_for_each_window() {
-	awk 'BEGIN { FS="\t"; OFS="\t" } /^pane/ && $7 != 0 && $9 == 1 { print $2, $3, $7; }' $(last_session_path) |
+	awk 'BEGIN { FS="\t"; OFS="\t" } /^pane/ && $9 == 1 { print $2, $3, $7; }' $(last_resurrect_file) |
 		while IFS=$'\t' read session_name window_number active_pane; do
 			tmux switch-client -t "${session_name}:${window_number}"
 			tmux select-pane -t "$active_pane"
 		done
 }
 
+restore_zoomed_windows() {
+	awk 'BEGIN { FS="\t"; OFS="\t" } /^window/ && $5 ~ /Z/ { print $2, $3; }' $(last_resurrect_file) |
+		while IFS=$'\t' read session_name window_number; do
+			tmux resize-pane -t "${session_name}:${window_number}" -Z
+		done
+}
+
 restore_active_and_alternate_windows() {
-	awk 'BEGIN { FS="\t"; OFS="\t" } /^window/ && $5 ~ /[*-]/ { print $2, $4, $3; }' $(last_session_path) |
+	awk 'BEGIN { FS="\t"; OFS="\t" } /^window/ && $5 ~ /[*-]/ { print $2, $4, $3; }' $(last_resurrect_file) |
 		sort -u |
 		while IFS=$'\t' read session_name active_window window_number; do
 			tmux switch-client -t "${session_name}:${window_number}"
@@ -145,20 +187,22 @@ restore_active_and_alternate_sessions() {
 		if is_line_type "state" "$line"; then
 			restore_state "$line"
 		fi
-	done < $(last_session_path)
+	done < $(last_resurrect_file)
 }
 
 main() {
-	if supported_tmux_version_ok; then
+	if supported_tmux_version_ok && check_saved_session_exists; then
-		check_saved_session_exists
+		start_spinner
-		restore_all_sessions
+		restore_all_panes
-		restore_all_pane_processes
 		restore_pane_layout_for_each_window >/dev/null 2>&1
+		restore_all_pane_processes
 		# below functions restore exact cursor positions
 		restore_active_pane_for_each_window
+		restore_zoomed_windows
 		restore_active_and_alternate_windows
 		restore_active_and_alternate_sessions
-		display_message "Restored all Tmux sessions!"
+		stop_spinner
+		display_message "Tmux restore complete!"
 	fi
 }
 main

scripts/save.sh

@@ -2,6 +2,7 @@
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
+source "$CURRENT_DIR/scripts/variables.sh"
 source "$CURRENT_DIR/helpers.sh"
 
 pane_format() {
@@ -21,7 +22,7 @@ pane_format() {
 	format+="${delimiter}"
 	format+="#{pane_index}"
 	format+="${delimiter}"
-	format+="#{pane_current_path}"
+	format+=":#{pane_current_path}"
 	format+="${delimiter}"
 	format+="#{pane_active}"
 	format+="${delimiter}"
@@ -88,19 +89,19 @@ dump_state() {
 	tmux display-message -p "$(state_format)"
 }
 
-save_all_sessions() {
+save_all() {
-	local session_path="$(session_path)"
+	local resurrect_file_path="$(resurrect_file_path)"
-	mkdir -p "$(sessions_dir)"
+	mkdir -p "$(resurrect_dir)"
-	dump_panes   >  $session_path
+	dump_panes   >  $resurrect_file_path
-	dump_windows >> $session_path
+	dump_windows >> $resurrect_file_path
-	dump_state   >> $session_path
+	dump_state   >> $resurrect_file_path
-	ln -fs "$session_path" "$(last_session_path)"
+	ln -fs "$resurrect_file_path" "$(last_resurrect_file)"
-	display_message "Saved all Tmux sessions!"
+	display_message "Tmux environment saved!"
 }
 
 main() {
 	if supported_tmux_version_ok; then
-		save_all_sessions
+		save_all
 	fi
 }
 main

scripts/spinner_helpers.sh

@@ -0,0 +1,8 @@
+start_spinner() {
+	$CURRENT_DIR/tmux_spinner.sh "Restoring tmux..." "Tmux restore complete!" &
+	export SPINNER_PID=$!
+}
+
+stop_spinner() {
+	kill $SPINNER_PID
+}

scripts/tmux_spinner.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+# This script shows tmux spinner with a message. It is intended to be running
+# as a background process which should be `kill`ed at the end.
+#
+# Example usage:
+#
+#   ./tmux_spinner.sh "Working..." "End message!" &
+#   SPINNER_PID=$!
+#   ..
+#   .. execute commands here
+#   ..
+#   kill $SPINNER_PID # Stops spinner and displays 'End message!'
+
+MESSAGE="$1"
+END_MESSAGE="$2"
+SPIN='-\|/'
+
+trap "tmux display-message $END_MESSAGE; exit" SIGINT SIGTERM
+
+main() {
+	local i=0
+	while true; do
+	  i=$(( (i+1) %4 ))
+	  tmux display-message " ${SPIN:$i:1} $MESSAGE"
+	  sleep 0.1
+	done
+}
+main

scripts/variables.sh

@@ -0,0 +1,23 @@
+# key bindings
+default_save_key="M-s"
+save_option="@resurrect-save"
+
+default_restore_key="M-r"
+restore_option="@resurrect-restore"
+
+# default processes that are restored
+default_proc_list_option="@resurrect-default-processes"
+default_proc_list='vi vim emacs man less more tail top htop irssi irb pry "~rails console"'
+
+# User defined processes that are restored
+#  'false' - nothing is restored
+#  ':all:' - all processes are restored
+#
+# user defined list of programs that are restored:
+#  'my_program foo another_program'
+restore_processes_option="@resurrect-processes"
+restore_processes=""
+
+# Defines part of the user variable. Example usage:
+#   set -g @resurrect-strategy-vim "session"
+restore_process_strategy_option="@resurrect-strategy-"

strategies/irb_default_strategy.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+# "irb default strategy"
+#
+# Example irb process with junk variables:
+#   irb RBENV_VERSION=1.9.3-p429 GREP_COLOR=34;47 TERM_PROGRAM=Apple_Terminal
+#
+# When executed, the above will fail. This strategy handles that.
+
+ORIGINAL_COMMAND="$1"
+DIRECTORY="$2"
+
+original_command_wo_junk_vars() {
+	echo "$ORIGINAL_COMMAND" |
+		sed 's/RBENV_VERSION[^ ]*//' |
+		sed 's/GREP_COLOR[^ ]*//'    |
+		sed 's/TERM_PROGRAM[^ ]*//'
+}
+
+main() {
+	echo "$(original_command_wo_junk_vars)"
+}
+main

strategies/vim_session.sh

@@ -4,7 +4,7 @@
 #
 # Restores a vim session from 'Session.vim' file, if it exists.
 # If 'Session.vim' does not exist, it falls back to invoking the original
-# command.
+# command (without the `-S` flag).
 
 ORIGINAL_COMMAND="$1"
 DIRECTORY="$2"
@@ -13,9 +13,18 @@ vim_session_file_exists() {
 	[ -e "${DIRECTORY}/Session.vim" ]
 }
 
+original_command_contains_session_flag() {
+	[[ "$ORIGINAL_COMMAND" =~ "-S" ]]
+}
+
 main() {
 	if vim_session_file_exists; then
 		echo "vim -S"
+	elif original_command_contains_session_flag; then
+		# Session file does not exist, yet the original vim command contains
+		# session flag `-S`. This will cause an error, so we're falling back to
+		# starting plain vim.
+		echo "vim"
 	else
 		echo "$ORIGINAL_COMMAND"
 	fi