Language server "Building sketch..." spinner seems to hang

[sterretjeToo]

I did try to find this but did not see it.

IDE 1.8.5 is installed as the main IDE, RC2 is installed as a zip. Using Windows 10 home, fully patched.

1. I left the IDE open last night with a sketch for an Uno Wifi Rev2; this sketch was not saved.
2. This morning I copied a (non Uno Wifi Rev2) sketch from the forum and pasted it over the existing sketch; the new sketch is 242 lines and contains a error.
3. I pressed <ctrl>T; this might not be relevant.
4. I noticed that the status bar showed "building sketch".
5. More than 30 minutes later, the message was still there; I noticed one message about indexing but that disappeared again.
6. Closed the IDE and restarted it; empty sketch (no problem for me)
7. Pasted the forum sketch again
8. "Building sketch" shows again in the status bar, this time it does not hang and the message inthe status bar disappears.

I would expect the build process of the sketch to complete.

This might just have been a glitch; reported as an observation.

[per1234]

There is a related report about the "indexing" stage of the language server sketch processing operation hanging:
#431
I have periodically encountered that one. I don't remember observing a hang at "building" though, so I think it is worth tracking it as a separate issue for now.

[ubidefeo]

@cmaglie
this is certainly due to the LS being killed by the IDE after a long time.

@sterretjeToo
we are still looking for the source of the issue, but essentially a kill command is sent tot he language server at unpredictable times.
The criticality of this bug has been upped.

[fstasi]

this should be fixed with IDE rc7

[per1234]

@fstasi I looked at the 2.0.0-rc7 release PR (#1027) and it doesn't appear there is anything in it that could possibly affect this behavior (it only updates the version metadata).

Was it #1021 that is expected to fix this issue?

[qwertychouskie]

This could also be related to #714