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Allow bash-preexec to be included at any point #110

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merged 5 commits into from
Aug 22, 2020
Merged

Allow bash-preexec to be included at any point #110

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846654a
Allow bash-preexec to be included at any point
rcaloras Aug 20, 2020
d77e6a8
Removing a few empty lines
rcaloras Aug 20, 2020
51296f7
Handle cases for manipulating PROMPT_COMMAND
rcaloras Aug 21, 2020
c4c69c4
Adjusting comment for edge case
rcaloras Aug 21, 2020
c0fb0c0
Fix 'in prompt command'. Don't eval PROMPT_COMMAND
rcaloras Aug 22, 2020
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64 changes: 40 additions & 24 deletions bash-preexec.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,9 @@ __bp_last_argument_prev_command="$_"
__bp_inside_precmd=0
__bp_inside_preexec=0

# Initial PROMPT_COMMAND string that is removed from PROMPT_COMMAND post __bp_install
__bp_install_string=$'__bp_trap_string="$(trap -p DEBUG)"\ntrap - DEBUG\n__bp_install'

# Fails if any of the given variables are readonly
# Reference https://stackoverflow.com/a/4441178
__bp_require_not_readonly() {
Expand Down Expand Up @@ -89,6 +92,19 @@ __bp_trim_whitespace() {
echo -n "$var"
}


# Returns a copy of the passed in string trimmed of whitespace
# and removes any leading or trailing semi colons.
# Used for manipulating substrings in PROMPT_COMMAND
__bp_sanitize_string() {
local sanitized_string
sanitized_string=$(__bp_trim_whitespace "${1:-}")
sanitized_string=${sanitized_string%;}
sanitized_string=${sanitized_string#;}
sanitized_string=$(__bp_trim_whitespace "$sanitized_string")
echo -n "$sanitized_string"
}

# This function is installed as part of the PROMPT_COMMAND;
# It sets a variable to indicate that the prompt was just displayed,
# to allow the DEBUG trap to know that the next command is likely interactive.
Expand Down Expand Up @@ -136,7 +152,7 @@ __bp_set_ret_value() {
__bp_in_prompt_command() {

local prompt_command_array
IFS=';' read -ra prompt_command_array <<< "$PROMPT_COMMAND"
IFS=$'\n;' read -rd '' -a prompt_command_array <<< "$PROMPT_COMMAND"

local trimmed_arg
trimmed_arg=$(__bp_trim_whitespace "${1:-}")
Expand All @@ -159,6 +175,7 @@ __bp_in_prompt_command() {
# environment to attempt to detect if the current command is being invoked
# interactively, and invoke 'preexec' if so.
__bp_preexec_invoke_exec() {

# Save the contents of $_ so that it can be restored later on.
# https://stackoverflow.com/questions/40944532/bash-preserve-in-a-debug-trap#40944702
__bp_last_argument_prev_command="${1:-}"
Expand Down Expand Up @@ -266,7 +283,6 @@ __bp_install() {
# Adjust our HISTCONTROL Variable if needed.
__bp_adjust_histcontrol


# Issue #25. Setting debug trap for subshells causes sessions to exit for
# backgrounded subshell commands (e.g. (pwd)& ). Believe this is a bug in Bash.
#
Expand All @@ -278,24 +294,33 @@ __bp_install() {
shopt -s extdebug > /dev/null 2>&1
fi;

local __bp_existing_prompt_command
# Remove setting our trap install string and sanitize the existing prompt command string
__bp_existing_prompt_command="${PROMPT_COMMAND//$__bp_install_string[;$'\n']}" # Edge case of appending to PROMPT_COMMAND
__bp_existing_prompt_command="${__bp_existing_prompt_command//$__bp_install_string}"
__bp_existing_prompt_command=$(__bp_sanitize_string "$__bp_existing_prompt_command")

# Install our hooks in PROMPT_COMMAND to allow our trap to know when we've
# actually entered something.
PROMPT_COMMAND="__bp_precmd_invoke_cmd; __bp_interactive_mode"
PROMPT_COMMAND=$'__bp_precmd_invoke_cmd\n'
if [[ -n "$__bp_existing_prompt_command" ]]; then
PROMPT_COMMAND+=${__bp_existing_prompt_command}$'\n'
fi;
PROMPT_COMMAND+='__bp_interactive_mode'

# Add two functions to our arrays for convenience
# of definition.
precmd_functions+=(precmd)
preexec_functions+=(preexec)

# Since this function is invoked via PROMPT_COMMAND, re-execute PC now that it's properly set
eval "$PROMPT_COMMAND"
# Invoke our two functions manually that were added to $PROMPT_COMMAND
__bp_precmd_invoke_cmd
__bp_interactive_mode
}

# Sets our trap and __bp_install as part of our PROMPT_COMMAND to install
# Sets an installation string as part of our PROMPT_COMMAND to install
# after our session has started. This allows bash-preexec to be included
# at any point in our bash profile. Ideally we could set our trap inside
# __bp_install, but if a trap already exists it'll only set locally to
# the function.
# at any point in our bash profile.
__bp_install_after_session_init() {

# Make sure this is bash that's running this and return otherwise.
Expand All @@ -307,21 +332,12 @@ __bp_install_after_session_init() {
# if it can't, just stop the installation
__bp_require_not_readonly PROMPT_COMMAND HISTCONTROL HISTTIMEFORMAT || return

# If there's an existing PROMPT_COMMAND capture it and convert it into a function
# So it is preserved and invoked during precmd.
if [[ -n "${PROMPT_COMMAND:-}" ]]; then
eval '__bp_original_prompt_command() {
'"$PROMPT_COMMAND"'
}'
precmd_functions+=(__bp_original_prompt_command)
fi

# Installation is finalized in PROMPT_COMMAND, which allows us to override the DEBUG
# trap. __bp_install sets PROMPT_COMMAND to its final value, so these are only
# invoked once.
# It's necessary to clear any existing DEBUG trap in order to set it from the install function.
# Using \n as it's the most universal delimiter of bash commands
PROMPT_COMMAND=$'\n__bp_trap_string="$(trap -p DEBUG)"\ntrap - DEBUG\n__bp_install\n'
local sanitized_prompt_command
sanitized_prompt_command=$(__bp_sanitize_string "$PROMPT_COMMAND")
if [[ -n "$sanitized_prompt_command" ]]; then
PROMPT_COMMAND=${sanitized_prompt_command}$'\n'
fi;
PROMPT_COMMAND+=${__bp_install_string}
}

# Run our install so long as we're not delaying it.
Expand Down
77 changes: 75 additions & 2 deletions test/bash-preexec.bats
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Original file line number Diff line number Diff line change
Expand Up @@ -68,13 +68,86 @@ test_preexec_echo() {
(( trap_count_snapshot < trap_invoked_count ))
}

@test "PROMPT_COMMAND=\"\$PROMPT_COMMAND; foo\" should work" {
@test "__bp_sanitize_string should remove semicolons and trim space" {

run '__bp_sanitize_string' " true1; "$'\n'
[ $status -eq 0 ]
[ "$output" == "true1" ]

run '__bp_sanitize_string' " ; true2; "
[ $status -eq 0 ]
[ "$output" == "true2" ]

run '__bp_sanitize_string' $'\n'" ; true3; "
[ $status -eq 0 ]
[ "$output" == "true3" ]

}

@test "Appending to PROMPT_COMMAND should work after bp_install" {
bp_install

PROMPT_COMMAND="$PROMPT_COMMAND; true"
eval "$PROMPT_COMMAND"
}

@test "Appending or prepending to PROMPT_COMMAND should work after bp_install_after_session_init" {
__bp_install_after_session_init
nl=$'\n'
PROMPT_COMMAND="$PROMPT_COMMAND; true"
PROMPT_COMMAND="$PROMPT_COMMAND $nl true"
PROMPT_COMMAND="$PROMPT_COMMAND; true"
PROMPT_COMMAND="true; $PROMPT_COMMAND"
PROMPT_COMMAND="true; $PROMPT_COMMAND"
PROMPT_COMMAND="true; $PROMPT_COMMAND"
PROMPT_COMMAND="true $nl $PROMPT_COMMAND"
eval "$PROMPT_COMMAND"
}

# Case where a user is appending or prepending to PROMPT_COMMAND.
# This can happen after 'source bash-preexec.sh' e.g.
# source bash-preexec.sh; PROMPT_COMMAND="$PROMPT_COMMAND; other_prompt_command_hook"
@test "Adding to PROMPT_COMMAND before and after initiating install" {
PROMPT_COMMAND="echo before"
PROMPT_COMMAND="$PROMPT_COMMAND; echo before2"
__bp_install_after_session_init
PROMPT_COMMAND="$PROMPT_COMMAND"$'\n echo after'
PROMPT_COMMAND="echo after2; $PROMPT_COMMAND;"

eval "$PROMPT_COMMAND"

expected_result=$'__bp_precmd_invoke_cmd\necho after2; echo before; echo before2\n echo after\n__bp_interactive_mode'
[ "$PROMPT_COMMAND" == "$expected_result" ]
}

@test "Adding to PROMPT_COMMAND after with semicolon" {
PROMPT_COMMAND="echo before"
__bp_install_after_session_init
PROMPT_COMMAND="$PROMPT_COMMAND; echo after"

eval "$PROMPT_COMMAND"

expected_result=$'__bp_precmd_invoke_cmd\necho before\n echo after\n__bp_interactive_mode'
[ "$PROMPT_COMMAND" == "$expected_result" ]
}

@test "during install PROMPT_COMMAND and precmd functions should be executed each once" {
PROMPT_COMMAND="echo before"
PROMPT_COMMAND="$PROMPT_COMMAND; echo before2"
__bp_install_after_session_init
PROMPT_COMMAND="$PROMPT_COMMAND; echo after"
PROMPT_COMMAND="echo after2; $PROMPT_COMMAND;"

precmd() { echo "inside precmd"; }
run eval "$PROMPT_COMMAND"
[ "${lines[0]}" == "after2" ]
[ "${lines[1]}" == "before" ]
[ "${lines[2]}" == "before2" ]
[ "${lines[3]}" == "inside precmd" ]
[ "${lines[4]}" == "after" ]
[ "${#lines[@]}" == '5' ]
}

@test "No functions defined for preexec should simply return" {
__bp_interactive_mode

Expand Down Expand Up @@ -213,7 +286,7 @@ test_preexec_echo() {

@test "in_prompt_command should detect if a command is part of PROMPT_COMMAND" {

PROMPT_COMMAND="precmd_invoke_cmd; something;"
PROMPT_COMMAND=$'precmd_invoke_cmd\n something; echo yo\n __bp_interactive_mode'
run '__bp_in_prompt_command' "something"
[ $status -eq 0 ]

Expand Down