With the zed latex extension, Previewer opens often in the wrong position

[mocenigo]

Actual cursor position and position in fwd_search.rs / ForwardSearch differ.

I am using Zed Zed 0.154.3 and the texlab 5.19.0 with zed-latex 0.0.7. My PDF previewer is Skim.

I often observe that upon saving, the Previewer does not open in the position where the cursor was in the tex file at the moment I actually saved. It is usually a previous position, and only after I edit a bit the posizion is adjourned. To reproduce, I also do not move the cursor after hitting cmd-S until the Previewer comes to the foreground.

I thus re-compiled texlab with debugging log force-activated and a separated log file, in fwd_search.rs I added outputs for child, child.cursor and line (such as log::debug!("[FwdSearch] child={:?}", &child);) and I can read the following in the log output:

DEBUG - [FwdSearch] child=Document("file:///Users/mocenigo/Research/PAC-Analysis/paper_short/truncated-reduced.tex")
DEBUG - [FwdSearch] child.cursor=LineCol { line: 0, col: 0 }
DEBUG - [FwdSearch] line="1"

whereas I know I have moevd to line 955 and the position given in the same log a few lines before is

DEBUG - < {"jsonrpc":"2.0","id":3,"method":"textDocument/documentHighlight","params":{"textDocument":{"uri":"file:///Users/mocenigo/Research/PAC-Analysis/paper_short/truncated-reduced.tex"},"position":{"line":955,"character":16}}}

Even if a movement of the cursor is finally detected, the two places are often out of sync and the Previewer opens in the wrong place.

I do not know whether the bug is in texlab or caused by a bug in Zed.

[pfoerster]

I do not know whether the bug is in texlab or caused by a bug in Zed.

The issue lies within LSP itself. With the current protocol, the server has to guess the cursor position before triggering the forward search (there is no request to query the cursor position).

The easiest way to fix this issue would be to:

1. Disable texlab.build.onSave
2. Trigger the build manually and set the optional position parameter to the cursor position.

Then, the server knows the position and does not need guess where the cursor is currently at.

[mocenigo]

I do not know whether the bug is in texlab or caused by a bug in Zed.

The issue lies within LSP itself. With the current protocol, the server has to guess the cursor position before triggering the forward search (there is no request to query the cursor position).

The easiest way to fix this issue would be to:

1. Disable texlab.build.onSave
2. Trigger the build manually and set the optional position parameter to the cursor position.

Then, the server knows the position and does not need guess where the cursor is currently at.

OK 1, is easiky done. How does one do 2)?
I actually hate that the file is recompiled at each save, but it was my understanding that triggering the build manually was not possible. Of course with multiple cursors one has to pick one, I would say the first.

[pfoerster]

How does one do 2)?

This needs to be done manually in the editor. You can use these requests:

https://github.com/latex-lsp/texlab/wiki/LSP-Internals#custom-messages