blob: ab746724e91539f7ab1b293f97c797896a5d222d [file] [log] [blame]
#!/usr/bin/env bash
# Copyright 2014 The Flutter Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
# ---------------------------------- NOTE ---------------------------------- #
# Please keep the logic in this file consistent with the logic in the
# `shared.bat` script in the same directory to ensure that Flutter & Dart continue
# to work across all platforms!
# -------------------------------------------------------------------------- #
set -e
# Needed because if it is set, cd may print the path it changed to.
unset CDPATH
function pub_upgrade_with_retry {
local total_tries="10"
local remaining_tries=$((total_tries - 1))
while [[ "$remaining_tries" -gt 0 ]]; do
(cd "$FLUTTER_TOOLS_DIR" && "$DART" __deprecated_pub upgrade "$VERBOSITY" --no-precompile) && break
>&2 echo "Error: Unable to 'pub upgrade' flutter tool. Retrying in five seconds... ($remaining_tries tries left)"
remaining_tries=$((remaining_tries - 1))
sleep 5
if [[ "$remaining_tries" == 0 ]]; then
>&2 echo "Command 'pub upgrade' still failed after $total_tries tries, giving up."
return 1
return 0
# Trap function for removing any remaining lock file at exit.
function _rmlock () {
# Determines which lock method to use, based on what is available on the system.
# Returns a non-zero value if the lock was not acquired, zero if acquired.
function _lock () {
if hash flock 2>/dev/null; then
flock --nonblock --exclusive 7 2>/dev/null
elif hash shlock 2>/dev/null; then
shlock -f "$1" -p $$
mkdir "$1" 2>/dev/null
# Waits for an update lock to be acquired.
# To ensure that we don't simultaneously update Dart in multiple parallel
# instances, we try to obtain an exclusive lock on this file descriptor (and
# thus this script's source file) while we are updating Dart and compiling the
# script. To do this, we try to use the command line program "flock", which is
# available on many Unix-like platforms, in particular on most Linux
# distributions. You give it a file descriptor, and it locks the corresponding
# file, having inherited the file descriptor from the shell.
# Complicating matters, there are two major scenarios where this will not
# work.
# The first is if the platform doesn't have "flock", for example on macOS. There
# is not a direct equivalent, so on platforms that don't have flock, we fall
# back to using trying to use the shlock command, and if that doesn't exist,
# then we use mkdir as an atomic operation to create a lock directory. If mkdir
# is able to create the directory, then the lock is acquired. To determine if we
# have "flock" or "shlock" available, we use the "hash" shell built-in.
# The second complication is on network file shares. On NFS, to obtain an
# exclusive lock you need a file descriptor that is open for writing. Thus, we
# ignore errors from flock by redirecting all output to /dev/null, since users
# will typically not care about errors from flock and are more likely to be
# confused by them than helped. The "shlock" method doesn't work for network
# shares, since it is PID-based. The "mkdir" method does work over NFS
# implementations that support atomic directory creation (which is most of
# them). The "schlock" and "flock" commands are more reliable than the mkdir
# method, however, or we would use mkdir in all cases.
# The upgrade_flutter function calling _wait_for_lock is executed in a subshell
# with a redirect that pipes the source of this script into file descriptor 7.
# A flock lock is released when this subshell exits and file descriptor 7 is
# closed. The mkdir lock is released via an exit trap from the subshell that
# deletes the lock directory.
function _wait_for_lock () {
local waiting_message_displayed
while ! _lock "$FLUTTER_UPGRADE_LOCK"; do
if [[ -z $waiting_message_displayed ]]; then
# Print with a return so that if the Dart code also prints this message
# when it does its own lock, the message won't appear twice. Be sure that
# the clearing printf below has the same number of space characters.
printf "Waiting for another flutter command to release the startup lock...\r" >&2;
sleep .1;
if [[ $waiting_message_displayed == "true" ]]; then
# Clear the waiting message so it doesn't overlap any following text.
printf " \r" >&2;
unset waiting_message_displayed
# If the lock file is acquired, make sure that it is removed on exit.
trap _rmlock INT TERM EXIT
# This function is always run in a subshell. Running the function in a subshell
# is required to make sure any lock directory is cleaned up by the exit trap in
# _wait_for_lock.
function upgrade_flutter () (
mkdir -p "$FLUTTER_ROOT/bin/cache"
local revision="$(cd "$FLUTTER_ROOT"; git rev-parse HEAD)"
local compilekey="$revision:$FLUTTER_TOOL_ARGS"
# Invalidate cache if:
# * SNAPSHOT_PATH is not a file, or
# * STAMP_PATH is not a file, or
# * STAMP_PATH is an empty file, or
# * Contents of STAMP_PATH is not what we are going to compile, or
# * pubspec.yaml last modified after pubspec.lock
if [[ ! -f "$SNAPSHOT_PATH" || ! -s "$STAMP_PATH" || "$(cat "$STAMP_PATH")" != "$compilekey" || "$FLUTTER_TOOLS_DIR/pubspec.yaml" -nt "$FLUTTER_TOOLS_DIR/pubspec.lock" ]]; then
# Waits for the update lock to be acquired. Placing this check inside the
# conditional allows the majority of flutter/dart installations to bypass
# the lock entirely, but as a result this required a second verification that
# the SDK is up to date.
# A different shell process might have updated the tool/SDK.
if [[ -f "$SNAPSHOT_PATH" && -s "$STAMP_PATH" && "$(cat "$STAMP_PATH")" == "$compilekey" && "$FLUTTER_TOOLS_DIR/pubspec.yaml" -ot "$FLUTTER_TOOLS_DIR/pubspec.lock" ]]; then
exit $?
# Fetch Dart...
rm -f "$FLUTTER_ROOT/version"
touch "$FLUTTER_ROOT/bin/cache/.dartignore"
>&2 echo Building flutter tool...
# Prepare packages...
if [[ "$CI" == "true" || "$BOT" == "true" || "$CONTINUOUS_INTEGRATION" == "true" || "$CHROME_HEADLESS" == "1" ]]; then
export PUB_ENVIRONMENT="$PUB_ENVIRONMENT:flutter_install"
if [[ -d "$FLUTTER_ROOT/.pub-cache" ]]; then
export PUB_CACHE="${PUB_CACHE:-"$FLUTTER_ROOT/.pub-cache"}"
# Compile...
"$DART" --verbosity=error --disable-dart-dev $FLUTTER_TOOL_ARGS --snapshot="$SNAPSHOT_PATH" --packages="$FLUTTER_TOOLS_DIR/.dart_tool/package_config.json" --no-enable-mirrors "$SCRIPT_PATH"
echo "$compilekey" > "$STAMP_PATH"
# The exit here is extraneous since the function is run in a subshell, but
# this serves as documentation that running the function in a subshell is
# required to make sure any lock directory created by mkdir is cleaned up.
exit $?
# This function is intended to be executed by entrypoints (e.g. `//bin/flutter`
# and `//bin/dart`). PROG_NAME and BIN_DIR should already be set by those
# entrypoints.
function shared::execute() {
export FLUTTER_ROOT="$(cd "${BIN_DIR}/.." ; pwd -P)"
# If present, run the bootstrap script first
if [ -f "$BOOTSTRAP_PATH" ]; then
# If running over git-bash, overrides the default UNIX executables with win32
# executables
case "$(uname -s)" in
# Test if running as superuser – but don't warn if running within Docker or CI.
if [[ "$EUID" == "0" && ! -f /.dockerenv && "$CI" != "true" && "$BOT" != "true" && "$CONTINUOUS_INTEGRATION" != "true" ]]; then
>&2 echo " Woah! You appear to be trying to run flutter as root."
>&2 echo " We strongly recommend running the flutter tool without superuser privileges."
>&2 echo " /"
>&2 echo "📎"
# Test if Git is available on the Host
if ! hash git 2>/dev/null; then
>&2 echo "Error: Unable to find git in your PATH."
exit 1
# Test if the flutter directory is a git clone (otherwise git rev-parse HEAD
# would fail)
if [[ ! -e "$FLUTTER_ROOT/.git" ]]; then
>&2 echo "Error: The Flutter directory is not a clone of the GitHub project."
>&2 echo " The flutter tool requires Git in order to operate properly;"
>&2 echo " to install Flutter, see the instructions at:"
>&2 echo ""
exit 1
upgrade_flutter 7< "$PROG_NAME"
BIN_NAME="$(basename "$PROG_NAME")"
case "$BIN_NAME" in
# FLUTTER_TOOL_ARGS aren't quoted below, because it is meant to be
# considered as separate space-separated args.
exec "$DART" --disable-dart-dev --packages="$FLUTTER_TOOLS_DIR/.dart_tool/package_config.json" $FLUTTER_TOOL_ARGS "$SNAPSHOT_PATH" "$@"
exec "$DART" "$@"
>&2 echo "Error! Executable name $BIN_NAME not recognized!"
exit 1