the project server¶

by check asks a running language server for the project's diagnostics before checking for itself, and says so when it does:

$ by check
using project server information
All checks passed!

a server that has the project open has already parsed and inferred it, and has been keeping that current ever since. on a project of about twelve thousand files that is the difference between four seconds and under one

what it needs¶

the server has to be checking the whole project, which is not what an editor asks for by default — the default is only the files you have open. a server in that mode has never looked at the rest of the project, so it has no answer to give and does not pretend to:

{ "ty.diagnosticMode": "workspace" }

this is the same setting that decides whether errors in files you have not opened appear in your editor's problems list, so it is one you want anyway if you want this

it is the same answer, or it is no answer¶

what comes back is what your own process would have computed. the server refuses whenever that might not be true, and a refusal is not a failure — the check simply runs the way it always did, and you see no message

it refuses when the two are different builds of by, when they resolved different configuration, when they resolved different environments, when a file open in the editor has unsaved changes, and when the session is being typed into so fast that the check keeps being cancelled

any flag that changes the check is a different check. --python-version, --error-on-warning, --output-format and the rest all land in the configuration the two compare, so a by check carrying one of them is always run in full. so is a -v check, whose diagnostics carry an explanation of where each rule was turned on that a server's do not. and by check does not ask at all when the invocation is not a whole-project check: --watch, --fix, --add-ignore, or a check pointed at particular paths

the answer describes the project as it is on disk, not as your editor last noticed it — a git checkout your editor missed does not go unseen

finding out which one it was¶

every refusal is logged. -v will not show you, because a verbose check is itself a reason to refuse; ask for the log directly instead:

$ TY_LOG=ty=debug by check

turning it off¶

--no-server checks from scratch:

$ by check --no-server

BY_NO_PROJECT_SERVER=1 does the same, and does it on both halves: a command line with it set checks for itself, and a server started with it set does not open the socket that makes it reachable at all

$ BY_NO_PROJECT_SERVER=1 by check

what it opens¶

a server listens on a loopback port and writes a record of itself — the port and a random secret — into a per-user directory under ty's cache, readable only by you. a request without the secret is not answered, and an answer that does not repeat the secret back is not believed

the record is removed when the server shuts down. one whose server was killed outright stays behind until the next by check finds nothing listening and clears it away