Issue 1:
command

flutter doctor

exception

ArgumentError: Invalid argument(s): Invalid locale 'ia_FR.UTF-8'

#0 Intl._throwLocaleError (package:intl/intl.dart:231)
#1 Intl.verifiedLocale (package:intl/intl.dart:225)
#2 Intl.verifiedLocale (package:intl/intl.dart:210)
#3 new NumberFormat._forPattern (package:intl/src/intl/number_format.dart:486)
#4 new NumberFormat.decimalPattern (package:intl/src/intl/number_format.dart:175)
#5 kMillisecondsFormat (package:flutter_tools/src/base/utils.dart:97)
#6 kMillisecondsFormat (package:flutter_tools/src/base/utils.dart:97)
#7 getElapsedAsMilliseconds (package:flutter_tools/src/base/utils.dart:105)
#8 FlutterCommand.run (package:flutter_tools/src/runner/flutter_command.dart:202)
<asynchronous suspension>
#9 CommandRunner.runCommand (package:args/command_runner.dart:194)
<asynchronous suspension>
#10 FlutterCommandRunner.runCommand (package:flutter_tools/src/runner/flutter_command_runner.dart:279)
<asynchronous suspension>
#11 CommandRunner.run.<anonymous closure> (package:args/command_runner.dart:109)
#12 new Future.sync (dart:async/future.dart:222)
#13 CommandRunner.run (package:args/command_runner.dart:109)
#14 FlutterCommandRunner.run (package:flutter_tools/src/runner/flutter_command_runner.dart:162)
#15 run.<anonymous closure> (package:flutter_tools/runner.dart:89)
<asynchronous suspension>
#16 AppContext._run (package:flutter_tools/src/base/context.dart:76)
<asynchronous suspension>
#17 AppContext.runInZone.<anonymous closure> (package:flutter_tools/src/base/context.dart:66)
#18 _rootRun (dart:async/zone.dart:1120)
#19 _CustomZone.run (dart:async/zone.dart:1001)
#20 runZoned (dart:async/zone.dart:1467)
#21 AppContext.runInZone (package:flutter_tools/src/base/context.dart:65)
#22 run (package:flutter_tools/runner.dart:60)
<asynchronous suspension>
#23 main (package:flutter_tools/executable.dart:43)
<asynchronous suspension>
#24 main (file:///home/dawd/flutter/packages/flutter_tools/bin/flutter_tools.dart:16)
#25 _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:263)
#26 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:151)

flutter doctor

[✓] Flutter (on Linux, locale ia_FR.UTF-8, channel alpha)
• Flutter at /home/dawd/flutter
• Framework revision 8f65fec5f5 (5 weeks ago), 2017-12-12 09:50:14 -0800
• Engine revision edaecdc8b8
• Tools Dart version 1.25.0-dev.11.0
• Engine Dart version 2.0.0-edge.d8ae797298c3a6cf8dc9f4558707bd2672224d3e

[✓] Android toolchain - develop for Android devices (Android SDK 26.0.0)
• Android SDK at /home/dawd/Android/Sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-26, build-tools 26.0.0
• Java binary at: /usr/bin/java
• Java version Java(TM) SE Runtime Environment (build 1.8.0_131-b11)

[✗] Android Studio (not installed)
• Android Studio not found; download from https://developer.android.com/studio/index.html
(or visit https://flutter.io/setup/#android-setup for detailed instructions).

[✓] IntelliJ IDEA Community Edition (version 2017.3)
• Flutter plugin version 20.0.3
• Dart plugin version 173.4127.31

[-] Connected devices
• None

Issue 2:
Steps to Reproduce

when I run "flutter upgrade", the process gets exited unexpectedly after Downloading Material fonts... phase

command

flutter upgrade

exception

The null object does not have a getter 'length'.

NoSuchMethodError: method not found: 'length'

Receiver: null

Arguments: []

dart:core Object.noSuchMethod
package:flutter_tools/src/version.dart 110 _shortGitRevision
package:flutter_tools/src/version.dart 56 FlutterVersion.engineRevisionShort
package:flutter_tools/src/version.dart 64 FlutterVersion.toString
package:flutter_tools/src/commands/upgrade.dart 70 UpgradeCommand.runCommand.<async>
dart:async _SyncCompleter.complete
package:flutter_tools/src/base/process.dart 93 runCommandAndStreamOutput.<async>
===== asynchronous gap ===========================
dart:async _Completer.completeError
package:flutter_tools/src/commands/upgrade.dart 86 UpgradeCommand.runCommand.<async>
dart:async _SyncCompleter.complete
package:flutter_tools/src/base/process.dart 93 runCommandAndStreamOutput.<async>
===== asynchronous gap ===========================
dart:async _asyncThenWrapperHelper
package:flutter_tools/src/commands/upgrade.dart UpgradeCommand.runCommand
package:flutter_tools/src/runner/flutter_command.dart 150 FlutterCommand.verifyThenRunCommand.<async>
dart:async _SyncCompleter.complete
package:flutter_tools/src/cache.dart 184 Cache.updateAll.<async>
===== asynchronous gap ===========================
dart:async _asyncThenWrapperHelper
package:flutter_tools/src/runner/flutter_command.dart FlutterCommand.verifyThenRunCommand
package:flutter_tools/src/runner/flutter_command.dart 117 FlutterCommand.run
package:args/command_runner.dart 177 CommandRunner.runCommand.<fn>
dart:async Future.Future.sync
package:args/command_runner.dart 130 CommandRunner.runCommand
package:flutter_tools/src/runner/flutter_command_runner.dart 186 FlutterCommandRunner.runCommand.<async>
dart:async _SyncCompleter.complete
package:flutter_tools/src/cache.dart 71 Cache.lock.<async>
===== asynchronous gap ===========================
dart:async _asyncThenWrapperHelper
package:flutter_tools/src/runner/flutter_command_runner.dart FlutterCommandRunner.runCommand
package:args/command_runner.dart 104 CommandRunner.run.<fn>
dart:async Future.Future.sync
package:args/command_runner.dart 104 CommandRunner.run
package:flutter_tools/src/runner/flutter_command_runner.dart 132 FlutterCommandRunner.run
package:flutter_tools/executable.dart 97 main.<async>.<fn>.<async>
===== asynchronous gap ===========================
package:stack_trace Chain.capture
package:flutter_tools/executable.dart 91 main.<async>

flutter doctor

encountered exception: The null object does not have a getter 'length'.

NoSuchMethodError: method not found: 'length'
Receiver: null
Arguments: []

#0 Object._noSuchMethod (dart:core-patch/object_patch.dart:44)
#1 Object.noSuchMethod (dart:core-patch/object_patch.dart:47)
#2 _shortGitRevision (package:flutter_tools/src/version.dart:110)
#3 FlutterVersion.engineRevisionShort (package:flutter_tools/src/version.dart:56)
#4 _FlutterValidator.validate.<validate_async_body> (package:flutter_tools/src/doctor.dart:212)
#5 Future.Future.microtask.<anonymous closure> (dart:async/future.dart:144)
#6 StackZoneSpecification._run (package:stack_trace/src/stack_zone_specification.dart:206)
#7 StackZoneSpecification.registerCallback.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart:125)
#8 _rootRun (dart:async/zone.dart:1146)
#9 _CustomZone.run (dart:async/zone.dart:1026)
#10 _CustomZone.runGuarded (dart:async/zone.dart:924)
#11 _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:951)
#12 StackZoneSpecification._run (package:stack_trace/src/stack_zone_specification.dart:206)
#13 StackZoneSpecification.registerCallback.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart:125)
#14 _rootRun (dart:async/zone.dart:1150)
#15 _CustomZone.run (dart:async/zone.dart:1026)
#16 _CustomZone.runGuarded (dart:async/zone.dart:924)
#17 _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:951)
#18 _microtaskLoop (dart:async/schedule_microtask.dart:41)
#19 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50)
#20 _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:96)
#21 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:149)