Cached artifacts are not updated after switching channels

[timsneath]

See the following log. This was on an upgrade of the master channel on Windows 10. Notice that there are two attempts to download the Dart SDK, with different engine hashes.

C:\git\dart_console>flutter upgrade
Checking Dart SDK version...
Downloading Dart SDK from Flutter engine b875c7a5ff5680d3c734e3b94ba707b4f3a9527a...
Unzipping Dart SDK...
Building flutter tool...
Running pub upgrade...
Upgrading Flutter from C:\git\flutter...
From github.com:flutter/flutter
   48ce60824..3422540bc  master                  -> origin/master
 * [new branch]          Hixie-patch-2           -> origin/Hixie-patch-2
 * [new branch]          Hixie-patch-3           -> origin/Hixie-patch-3
 * [new branch]          Hixie-patch-4           -> origin/Hixie-patch-4
 + 2d2a1ffec...e70236e36 beta                    -> origin/beta  (forced update)
   3cf88fed6..1946fc4da  dev                     -> origin/dev
 * [new branch]          hot_restart_lowercase_r -> origin/hot_restart_lowercase_r
 * [new branch]          revert-40607-animationOverview -> origin/revert-40607-animationOverview
 * [new branch]          revert-40710-flutterGold -> origin/revert-40710-flutterGold
 * [new branch]          revert-41415-exposeimage -> origin/revert-41415-exposeimage
 * [new branch]          revert-41780-fix_build  -> origin/revert-41780-fix_build
 * [new branch]          sjindel.elf             -> origin/sjindel.elf
   2d2a1ffec..68587a091  stable                  -> origin/stable
   1ced75cc2..eb6877bf9  v1.9.1-hotfixes         -> origin/v1.9.1-hotfixes
 * [new tag]             v1.10.14                -> v1.10.14
 * [new tag]             v1.10.7                 -> v1.10.7
 * [new tag]             v1.9.1+hotfix.6         -> v1.9.1+hotfix.6
 * [new tag]             v1.10.10                -> v1.10.10
 * [new tag]             v1.10.11                -> v1.10.11
 * [new tag]             v1.10.12                -> v1.10.12
 * [new tag]             v1.10.13                -> v1.10.13
 * [new tag]             v1.10.6                 -> v1.10.6
 * [new tag]             v1.10.8                 -> v1.10.8
 * [new tag]             v1.10.9                 -> v1.10.9
 * [new tag]             v1.9.1+hotfix.3         -> v1.9.1+hotfix.3
 * [new tag]             v1.9.1+hotfix.4         -> v1.9.1+hotfix.4
 * [new tag]             v1.9.1+hotfix.5         -> v1.9.1+hotfix.5
Checking out files:  93% (1154/1229)
Checking out files:  94% (1156/1229)
Checking out files:  95% (1168/1229)
Checking out files:  96% (1180/1229)
Checking out files:  97% (1193/1229)
Checking out files:  98% (1205/1229)
Checking out files:  99% (1217/1229)
Checking out files: 100% (1229/1229)
Checking out files: 100% (1229/1229), done.
Updating 3cf88fed6..3422540bc
 .../AppIcon.appiconset/app_icon_1024.png           |  Bin 0 -> 46993 bytes
 .../AppIcon.appiconset/app_icon_128.png            |  Bin 0 -> 3276 bytes
 .../AppIcon.appiconset/app_icon_16.png             |  Bin 0 -> 1429 bytes
 .../AppIcon.appiconset/app_icon_256.png            |  Bin 0 -> 5933 bytes
 .../AppIcon.appiconset/app_icon_32.png             |  Bin 0 -> 1243 bytes
 .../AppIcon.appiconset/app_icon_512.png            |  Bin 0 -> 14800 bytes
 .../AppIcon.appiconset/app_icon_64.png             |  Bin 0 -> 1874 bytes
 .../AppIcon.appiconset/app_icon_1024.png           |  Bin 0 -> 46993 bytes
 .../AppIcon.appiconset/app_icon_128.png            |  Bin 0 -> 3276 bytes
 .../AppIcon.appiconset/app_icon_16.png             |  Bin 0 -> 1429 bytes
 .../AppIcon.appiconset/app_icon_256.png            |  Bin 0 -> 5933 bytes
 .../AppIcon.appiconset/app_icon_32.png             |  Bin 0 -> 1243 bytes
 .../AppIcon.appiconset/app_icon_512.png            |  Bin 0 -> 14800 bytes
 .../AppIcon.appiconset/app_icon_64.png             |  Bin 0 -> 1874 bytes
 .../hermetic}/devices_test.dart                    |    0
 .../hermetic}/install_test.dart                    |    0
 .../permeable}/format_test.dart                    |    0
 .../permeable}/upgrade_test.dart                   |    0
 1200 files changed, 58861 insertions(+), 20479 deletions(-)
Checking Dart SDK version...
Downloading Dart SDK from Flutter engine 8ea19b1c76f69f7b50e4195f41dfb1cb49a9fe66...
Unzipping Dart SDK...
Building flutter tool...
Running pub upgrade...

Upgrading engine...
Downloading Android Maven dependencies...                          15.6s
Downloading android-arm-profile/windows-x64 tools...                0.5s
Downloading android-arm-release/windows-x64 tools...                0.4s
Downloading android-arm64-profile/windows-x64 tools...              0.5s
Downloading android-arm64-release/windows-x64 tools...              0.4s
Downloading android-x64-profile/windows-x64 tools...                0.5s
Downloading android-x64-release/windows-x64 tools...                0.6s
Downloading android-x86 tools...                                    2.0s
Downloading android-x64 tools...                                    1.9s
Downloading android-arm tools...                                    1.0s
Downloading android-arm-profile tools...                            0.5s
Downloading android-arm-release tools...                            0.5s
Downloading android-arm64 tools...                                  0.9s
Downloading android-arm64-profile tools...                          0.6s
Downloading android-arm64-release tools...                          0.5s
Downloading android-x64-profile tools...                            0.6s
Downloading android-x64-release tools...                            0.5s
Downloading android-x86-jit-release tools...                        0.7s
Downloading package sky_engine...                                   0.2s
Downloading common tools...                                         0.9s
Downloading common tools...                                         1.0s
Downloading windows-x64 tools...                                    2.5s

Flutter 1.10.15-pre.387 • channel master • git@github.com:flutter/flutter.git
Framework • revision 3422540bc4 (73 minutes ago) • 2019-11-04 09:09:20 -0800
Engine • revision 8ea19b1c76
Tools • Dart 2.6.0 (build 2.6.0-dev.8.2 bbe2ac28c9)

Running flutter doctor...
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel master, v1.10.15-pre.387, on Microsoft Windows [Version 10.0.18362.449], locale en-US)
[√] Android toolchain - develop for Android devices (Android SDK version 29.0.0)
[√] Android Studio (version 3.5)
[√] VS Code (version 1.39.2)
[!] Connected device
    ! No devices available

! Doctor found issues in 1 category.

C:\git\dart_console>

[timsneath]

Also see #14700, which @tvolkert opened and was allegedly fixed with #14702. Might or might not be related.

[zanderso]

#14700 looks unrelated. In the case here, the Dart SDK is downloaded once to build and run the flutter tool. It (or rather a newer 'it') is downloaded a second time as part of the upgrade. One could shift the 'upgrade' logic to the shell scripts to avoid the additional download, but that would run counter to an overall goal of having less logic in shell scripts.

[timsneath]

I think we need to re-evaluate the trade-off here. The cost of expecting users to download another 200MB+ of Dart is a significant friction point for users who are on metered connections. I suspect that is more critical than reducing shell script logic. But there are other potential solutions here, for example using dart2native?

[Hixie]

I don't think this is really a bug. It's not the normal path. The normal path is that you download the SDK from the Web site, which includes Dart, and everything works without a download. Then later you run "flutter upgrade", and it downloads Dart once.

To get into the state described here, you have to do something like switch channels then upgrade. The first Dart SDK download is really part of switching channels, not upgrading. We could explicitly make switching channels download the Dart SDK and compile the tool, like "upgrade" does, and then you would not see this anymore.

[timsneath]

Hmmm -- it feels like I've had this on a regular upgrade without changing channels (I don't change channels very often). Will keep an eye out. I'd be somewhat less worried if this only occurs with a channel switch.

…

On Thu, Nov 21, 2019 at 5:14 PM Ian Hickson ***@***.***> wrote: I don't think this is really a bug. It's not the normal path. The normal path is that you download the SDK from the Web site, which includes Dart, and everything works without a download. Then later you run "flutter upgrade", and it downloads Dart once. To get into the state described here, you have to do something like switch channels then upgrade. The first Dart SDK download is really part of switching channels, not upgrading. We could explicitly make switching channels download the Dart SDK and compile the tool, like "upgrade" does, and then you would not see this anymore. — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#44118?email_source=notifications&email_token=AARWL635HU5P2WD3KK6RSU3QU4W75A5CNFSM4JIXNASKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEE4GHLY#issuecomment-557343663>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AARWL6ZP3O65JNNPALWHN3DQU4W75ANCNFSM4JIXNASA> .

[Hixie]

I'm going to rename this to be about the channel switch case, but if you do find it occurs in other cases please file a new bug with precise steps to reproduce.