When a text buffer does not represent a document from a workspace Get…

[KirillOsenkov]

…OpenDocumentInCurrentContextWithChanges() will return null. Allow for that without a NullReferenceException.

Fixes #24625.

Ask Mode template

Customer scenario

In cases where the editor is hosting text with C# content type, but it's not added to any workspace, there is a null reference exception thrown because document is null. It may or may not be fatal depending on the circumstances (i.e. how the editor is hosted).

Bugs this fixes

#24625

Workarounds, if any

Don't host C# files without adding them to a workspace

Risk

Very low risk, just a null check.

Performance impact

A null check - no discernible perf impact.

Is this a regression from a previous update?

Root cause analysis

Need the new "Nullable Reference Types" to catch nullrefs early.

How was the bug found?

Hosting Roslyn outside of Visual Studio (VSMac, etc).

Test documentation updated?

[jasonmalinowski]

I'm guessing you want this in dev15.7.x?

This also seems like one of those "how did we ever miss this before..."...is there something subtle here or is this PR as obvious as it looks?

[jasonmalinowski]

Change is fine; I suspect you want this in dev15.7.x though.

[KirillOsenkov]

I guess it'd be nice to have in dev15.7.x, but it's not exactly blocking. What would I need to do to get this into dev15.7.x? Make a new PR, or retarget, rebase and force push this one?

Yes, it's just a simple null check, nothing non-obvious here. I'm guessing there aren't a lot of cases where a CSharp content-type buffer is not added to any workspace.

[jinujoseph]

@Pilchie for Ask mode bar check
@KirillOsenkov , once approved you can retarget to dev15.7.x branch

[Pilchie]

Yes, I'd be willing to take this for 15.7.

[KirillOsenkov]

Retargeted to dev15.7.x

[jasonmalinowski]

@Pilchie Retargeted, and looks like ask mode template already filled out.

[Pilchie]

@jasonmalinowski @KirillOsenkov - test failure? https://ci.dot.net/job/dotnet_roslyn/job/dev15.7.x/job/windows_release_unit64_prtest/359/.

Approved pending that being figured out.

[jasonmalinowski]

@dotnet-bot retest windows_release_unit32_prtest please.