Investigate how to best unbundle prepackaed langauges

[dbaeumer]

With VS Code 1.21 we started to support language packs. We should now start to think about how to best unbundle pre-packaged language and used language packs instead. This transition period should be for existing users as smooth as possible. So may be we still ship the pack and installed it if shipped. For new users it is OK to ask them to download a language pack.

[dbaeumer]

I propose to do the following to un-bundle the prepacked languages:

1. for the core languages we also create language packs and publish them to the market place except for English. This will always ship pre-bundled.
2. we ship all core languages bundled as well for the next n months.
3. when VS Code starts and the UI is in one of the core languages we download the translation from the market place and install the extension in the background. This requires work from @sandy081
4. when VS Code starts and detects an extension for one of the core languages we use the extension instead of the bundled one. We could even do some A/B testing here but since the translations should be the same there is no win. This requires work from @dbaeumer
5. after n months we remove the core languages from VS Code (except English). This require work from @dbaeumer (change build scripts)

This approach ensures a smart transition for users that already use a UI other than English. They basically don't see any differences to today.

For users that install a fresh version of Code at a point in time were we only ship English the experience would be as follows:

1. UI comes up in English.
2. a message is shown that there is a language pack for the UI language used by the OS and whether the user wants to install it. This message must be in English and the UI language used by the OS (the user might not speak English and with our current solution the UI would come up in the UI language of the OS). This requires work from @ramya-rao-a especially around the fact that we would need to present the string in English and the UI language. Ideas to get to the UI language strings would be:
   1. hard code them in the VS Core
   2. Use hidden tags in the market place (@sandy081 would this be feasible. Is there a size limit to tag values). This also requires to be online.
   3. Download the extension and have the strings in the package.json file of the extension. This also requires to be online.
3. if the user accepts the installation we will install the language pack and switch the UI language.

[dbaeumer]

@ramya-rao-a @sandy081 can you please read and comment.

[ramya-rao-a]

Sounds good. Hard coding the message in the core languages is the simplest way to go. Hidden tags for just one message feels like an overkill

[dbaeumer]

In my model we need to have the messages for all languages. Would be cool if someone runs in Bulgarian and he sees a message in Bulgarian and English. This is how Windows behaves as well.

[sandy081]

3. when VS Code starts and the UI is in one of the core languages we download the translation from the market place and install the extension in the background. This requires work from @sandy081

If this is when VS Code is bundled with core languages then Why do we need to download from Marketplace? I think this should be needed when VS Code is not bundled with core languages and user had set up VS Code before with one of the core languages.

When VS Code is not bundled with core languages, Downloading during start up will impact the start up performance (only the time we download) and what do we do if user is offline? I think we have two cases here:

Users with VS Code installed before and go through update cycle

• While updating, download the lang pack if the user is using a core lang pack. This will regress the behaviour that user cannot simply set the locale to other core languages. User has to install the language pack before setting.

• While updating, download all core language packs

Users with VS Code installed before and install/download VS Code again
Users with fresh install of VS Code

• Have the same experience as for new User?
• Did we think about a Installation wizard asking the language to pick?

Regarding message in OS Language, I would not go for tags. Hardcoding them for all languages is not practical. As @dbaeumer said, it can help for some (core+known) languages but not if there is a new. I think reading it from the package.json is a good option in which case we should come up with a property in package.json to be used. What if the extension does not provide the message in package.json? We might need a validation check while generating the vsix.

[dbaeumer]

If this is when VS Code is bundled with core languages then Why do we need to download from Marketplace?

To have a smooth migration for existing users. So we will switch them to language packs without them noticing and difference in the UI. If we first unbundle all core language then they will be promoted to download their language pack. This is to avoid that prompt.

We though about doing this in update, but we have different update stories for Mac, Windows, Deb, RPM and I was trying to come up with one solution instead of 4 :-).

New users will get a different experience (even for the current core language) since at some point we will ship English only. For them I think it is important that they see at least the 'language pack instsall message' in their UI language.

[sandy081]

To have a smooth migration for existing users. So we will switch them to language packs without them noticing and difference in the UI. If we first unbundle all core language then they will be promoted to download their language pack. This is to avoid that promp

I think it is a good idea to download the lang pack extensions from Marketplace while they are bundled with VS Code to prepare for next step. This would need confirmation from user to download. Downloading without asking might not be good. I think this can also be done while checking for the VS Code update and inform the user that update to next version of VS Code need to install so and so language pack extensions.

[dbaeumer]

Agree on the fact that we need to let the user know that we are donwloading language packs.