This will handle paths with symlinks that resolve to the same location.

* Refactor for iOS.

* For android_xxx_unopt_arm64&ios_xxx_unopt_arm, remove the _arm64/_arm suffix.
dart generated in host_xxx_unopt/host_xxx has an arch of x86_64 which supports arm64/arm.

* Remove suffixes for various archs.

Stop wrapping adb, gradle and ios logger output, and update terminal wrapping column dynamically. (#23592)

Subcommand output (gradle, adb, etc) is no longer wrapped, and wrapping notices when the terminal column width changes dynamically now.

Fixes #23267.
Fixes #23266.

Updating the --wrap-column help message to reflect reality.

This attempts to re-land #22656.

There are two changes from the original:

I turned off wrapping completely when not sending output to a terminal. Previously I had defaulted to wrapping at and arbitrary 100 chars in that case, just to keep long messages from being too long, but that turns out the be a bad idea because there are tests that are relying on the specific form of the output. It's also pretty arbitrary, and mostly people sending output to a non-terminal will want unwrapped text.

I found a better way to terminate ANSI color/bold sequences, so that they can be embedded within each other without needed quite as complex a dance with removing redundant sequences.

As part of these changes, I removed the Logger.supportsColor setter so that the one source of truth for color support is in AnsiTerminal.supportsColor.

*     Turn on line wrapping again in usage and status messages, adds ANSI color to doctor and analysis messages. (#22656)

    This turns on text wrapping for usage messages and status messages. When on a terminal, wraps to the width of the terminal. When writing to a non-terminal, wrap lines at a default column width (currently defined to be 100 chars). If --no-wrap is specified, then no wrapping occurs. If --wrap-column is specified, wraps to that column (if --wrap is on).

    Adds ANSI color to the doctor and analysis output on terminals. This is in this PR with the wrapping, since wrapping needs to know how to count visible characters in the presence of ANSI sequences. (This is just one more step towards re-implementing all of Curses for Flutter. :-)) Will not print ANSI sequences when sent to a non-terminal, or of --no-color is specified.

    Fixes ANSI color and bold sequences so that they can be combined (bold, colored text), and a small bug in indentation calculation for wrapping.

    Since wrapping is now turned on, also removed many redundant '\n's in the code.

Revert "Turn on line wrapping in usage and status messages, adds ANSI color to doctor and analysis messages. (#22656)" (#22759)

This reverts commit e4386321
because it breaks 160 benchmarks, and several devicelab tests,
due to changing the format of the output.

Turn on line wrapping in usage and status messages, adds ANSI color to doctor and analysis messages. (#22656)

This turns on text wrapping for usage messages and status messages. When on a terminal, wraps to the width of the terminal. When writing to a non-terminal, wrap lines at a default column width (currently defined to be 100 chars). If --no-wrap is specified, then no wrapping occurs. If --wrap-column is specified, wraps to that column (if --wrap is on).

Adds ANSI color to the doctor and analysis output on terminals. This is in this PR with the wrapping, since wrapping needs to know how to count visible characters in the presence of ANSI sequences. (This is just one more step towards re-implementing all of Curses for Flutter. :-)) Will not print ANSI sequences when sent to a non-terminal, or of --no-color is specified.

Fixes ANSI color and bold sequences so that they can be combined (bold, colored text), and a small bug in indentation calculation for wrapping.

Since wrapping is now turned on, also removed many redundant '\n's in the code.

* Improve documentation and clean up code.

* Remove "Note that".

The phrase "note that" is basically meaningless as a prefix to an
otherwise fine sentence.

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

All temporary directory start with `flutter_` and have their random component separated from the name by a period, as in `flutter_test_bundle.YFYQMY`.

I've tried to find some of the places where we didn't cleanly delete temporary directories, too. This greatly reduces, though it does not entirely eliminate, the directories we leave behind when running tests, especially `flutter_tools` tests.

While I was at it I standardized on `tempDir` as the variable name for temporary directories, since it was the most common, removing occurrences of `temp` and `tmp`, among others.

Also I factored out some common code that used to catch exceptions that happen on Windows, and made more places use that pattern.

This uses @kevmoo's completion package to do command line completion for flutter, and a new command "bash-completion" (with alias "zsh-completion") that will output the necessary shell script setup code, and adds the hidden command "completion" that does the actual completion.

Because it adds a dependency, I also had to do flutter update-packages --force-upgrade.

Fixes #18988.

(second attempt)

This reverts commit 4f1b6604.

We were already skipping the check in `flutter upgrade` but this also spawns `flutter precache` and `flutter doctor` which would still check and potentially output the message.

re-write flutter analyze (the single-shot and --flutter-repo) to use the analysis server

Revert "re-write flutter analyze (the single-shot and --flutter-repo) to use the analysis server (#16281)" (#16482)

This reverts commit 2f41ea54.

re-write flutter analyze (the single-shot and --flutter-repo) to use the analysis server

It's required to be set before we detect local engine.

Was broken by #15984

Follow-up comments to #15984

This updates AppContext per the recommendations in #15352

Fixes #15352

When running with --preview-dart-2, host variant of the engine is
required. Simulator builds, like device builds, should resolve
host_RUNTIMEVARIANT_OPTVARIANT, not host_RUNTIMEVARIANT_sim_OPTVARIANT.

Generate the "version" file from git tags.
Remove the old VERSION file and mentions of versions in pubspec.yaml files.
Replace the old update_versions.dart script with a new roll_dev.dart script.
Update "flutter channel".
Update "flutter upgrade", including making it transition from alpha to dev.
Update "flutter --version" and "flutter doctor".

* Fix handling --preview-dart-2 for ios

* final var

Rolling the Dart SDK to 2.0, with associated package updates.  

https://groups.google.com/forum/#!topic/flutter-dev/E22RdKAYjs8

This class lives in the Context and allows callers to "inject"
flag values, where flag values are first extracted from the
command arguments, then from the global arguments as a fallback.

* Move host build check until it's actually used

* Elaborate diagnostic message

This adds --preview-dart-2 flag that enables use of Dart 2.0 Frontend in Flutter tools.