Autobuild on subfiles doesn't work

[rzach]

Preliminary questions [Required]

Disable all the other extensions except for LaTeX Workshop, and check that you still see this issue. [Required]

You still see this issue?: Yes

Make sure to visit the wiki FAQ before filling an issue.

You visited the wiki?: Yes

If your issue is with compiling a document (not having to do with finding the root file of a project), check first that you can compile manually.

You can compile a TeX document manually?: Yes

Describe the bug [Required]

Autobuild does not work on files that use the subfiles class.

To Reproduce

Steps to reproduce the behavior:

1. Open a document with \documentclass{subfiles}
2. Make a change
3. Ctrl-S

Expected behavior

Build task runs

Logs [Required]

N/A -- no build takes place, so no log

LaTeX Workshop Output [Required]

To access the log, click the 'TeX' icon on the Activity Bar on the left side, select 'View Log Messages', then select 'View LaTeX Workshop extension log'.

[20:55:06] Initializing LaTeX Workshop.
[20:55:06] Creating file watcher for .pdf files.
[20:55:06] Creating LaTeX Workshop http and websocket server.
[20:55:07] LaTeX Workshop initialized.
[20:55:07] Found root file of this subfile from active editor: /home/zach/Downloads/test.tex
[20:55:07] Root file changed from: undefined to /home/zach/Downloads/test.tex. Find all dependencies.
[20:55:07] Instantiating a new file watcher for /home/zach/Downloads/test.tex
[20:55:07] Creating file watcher for .bib files.
[20:55:07] Parsing /home/zach/Downloads/test.tex
[20:55:07] Parse fls file.
[20:55:07] Server created on 127.0.0.1:35537
[20:55:07] Adding /home/zach/Downloads/test.tex to file watcher.
[20:55:07] Snippet data loaded.
[20:55:07] LaTeX Workshop version: 8.9.0

Developer Tools Console [Required]

To access the log, click 'help' -> 'Toggle Developer Tools. Paste anything suspicious.

Empty

Screenshots

If applicable, add screenshots to help explain your problem.

Desktop [Required]

• OS: Ubuntu 19.10
• VS Code version: 1.44.2
• Extension version: 8.9.0
• TeX distribution version: TeX Live 2019

Additional questions

Are you using LaTeX Workshop with VS Code Remote?

No

If the answer is Yes, please write which one you are using. Write the versions of the remote extension.

• Remote Containers/Remote SSH/Remote WSL
• Remote Extension Version: [e.g. 0.48.0]

Additional context

Add any other context about the problem here.

"latex-workshop.latex.rootFile.doNotPrompt": true
"latex-workshop.latex.rootFile.useSubFile": true

[jlelong]

I cannot reproduce your issue. See https://github.com/James-Yu/LaTeX-Workshop/wiki/Compile#the-root-file for details on how we deal with subfiles.

Note that in every subfile, you must specify which file is the main one in the form

\documenclass[main.tex]{subfiles}

If you cannot figure out how to solve your problem, please post a minimal working example.

[rzach]

Here's the example I use:
vscodetest.zip
I open the folder and have sub.tex open. On 8.6.0, when I make a change to the file and save, it auto-builds. On 8.7.0 and up, it does not. From the logs it looks like the extension only watches changes in the main file but not in the subfile.

Extension log on 8.6.0:

[09:42:38] Initializing LaTeX Workshop.
[09:42:38] Creating LaTeX Workshop http and websocket server.
[09:42:38] LaTeX Workshop initialized.
[09:42:38] Found root file from active editor: /home/zach/vscodetest/sub.tex
[09:42:38] Root file changed from: undefined to /home/zach/vscodetest/sub.tex. Find all dependencies.
[09:42:38] Instantiating a new file watcher for /home/zach/vscodetest/sub.tex
[09:42:38] Creating file watcher for .bib files.
[09:42:38] Parsing /home/zach/vscodetest/sub.tex
[09:42:38] Server created on 127.0.0.1:45809
[09:42:38] Adding /home/zach/vscodetest/sub.tex to file watcher.
[09:42:39] Snippet data loaded.
[09:42:39] LaTeX Workshop version: 8.6.0
[09:42:47] LOG command invoked.
[09:42:47] Found root file from active editor: /home/zach/vscodetest/sub.tex
[09:42:47] Root file remains unchanged from: /home/zach/vscodetest/sub.tex.
[09:42:54] Found root file from active editor: /home/zach/vscodetest/sub.tex
[09:42:54] Root file remains unchanged from: /home/zach/vscodetest/sub.tex.
[09:43:00] File watcher: responding to change in /home/zach/vscodetest/sub.tex
[09:43:00] Parsing /home/zach/vscodetest/sub.tex
[09:43:00] /home/zach/vscodetest/sub.tex changed. Auto build project.
[09:43:00] BUILD command invoked.
[09:43:00] Building root file: /home/zach/vscodetest/sub.tex
[09:43:00] Build root file /home/zach/vscodetest/sub.tex
[09:43:00] Recipe step 1: latexmk, -synctex=1,-interaction=nonstopmode,-file-line-error,-pdf,-outdir=/home/zach/vscodetest,/home/zach/vscodetest/sub
[09:43:00] LaTeX build process spawned. PID: 24955.
[09:43:00] LaTeX log parsed with 0 messages.
[09:43:00] Recipe of length 1 finished. PID: 24955.
[09:43:00] Successfully built /home/zach/vscodetest/sub.tex.
[09:43:00] No PDF viewer connected for /home/zach/vscodetest/sub.pdf
[09:43:00] Parse fls file.
[09:43:00] Parsing /home/zach/vscodetest/main.tex
[09:43:00] SyncTex after build invoked.
[09:43:00] Adding /home/zach/vscodetest/main.tex to file watcher.

Log on 8.7.0: (Making changes to sub.tex and saving doesn't do do anything, so nothing is written to the log when I do that.)

[09:47:44] Initializing LaTeX Workshop.
[09:47:44] Creating LaTeX Workshop http and websocket server.
[09:47:44] LaTeX Workshop initialized.
[09:47:44] Found root file of this subfile from active editor: /home/zach/vscodetest/main.tex
[09:47:44] Root file changed from: undefined to /home/zach/vscodetest/main.tex. Find all dependencies.
[09:47:44] Instantiating a new file watcher for /home/zach/vscodetest/main.tex
[09:47:44] Creating file watcher for .bib files.
[09:47:44] Parsing /home/zach/vscodetest/main.tex
[09:47:44] Server created on 127.0.0.1:41593
[09:47:44] Adding /home/zach/vscodetest/main.tex to file watcher.
[09:47:44] Snippet data loaded.
[09:47:44] LaTeX Workshop version: 8.7.0

Log on 8.9.0:

[09:48:55] Initializing LaTeX Workshop.
[09:48:55] Creating file watcher for .pdf files.
[09:48:55] Creating LaTeX Workshop http and websocket server.
[09:48:55] LaTeX Workshop initialized.
[09:48:55] Found root file of this subfile from active editor: /home/zach/vscodetest/main.tex
[09:48:55] Root file changed from: undefined to /home/zach/vscodetest/main.tex. Find all dependencies.
[09:48:55] Instantiating a new file watcher for /home/zach/vscodetest/main.tex
[09:48:55] Creating file watcher for .bib files.
[09:48:55] Parsing /home/zach/vscodetest/main.tex
[09:48:55] Parse fls file.
[09:48:55] Cannot find fls file.
[09:48:55] Server created on 127.0.0.1:35675
[09:48:55] Adding /home/zach/vscodetest/main.tex to file watcher.
[09:48:55] Snippet data loaded.
[09:48:55] LaTeX Workshop version: 8.9.0
[09:49:00] LOG command invoked.
[09:49:00] Found root file of this subfile from active editor: /home/zach/vscodetest/main.tex
[09:49:00] Root file remains unchanged from: /home/zach/vscodetest/main.tex.
[09:49:11] Found root file of this subfile from active editor: /home/zach/vscodetest/main.tex
[09:49:11] Root file remains unchanged from: /home/zach/vscodetest/main.tex.

[jlelong]

The issue is that your main.tex file does not reference sub.tex. The main file should look like

\documentclass{article}
\usepackage{subfiles}
\begin{document}
main
\subfile{sub}
\end{document}

You can check that with this modified main.tex, everything works fine.

There was actually a bug in 8.6.0, which lead sub.tex to be considered as the root file and not as a subfile of main.tex. This is why you thought it was working.

[rzach]

Unfortunately, in my projects, I cannot \subfile the actual file in main.tex (and subfiles does not require that this is done). Basically, main.tex just sets up things so that sub.tex can be compiled on its own. sub.tex is then used in a range of files; there is no actual main project file. There are hundreds of individual sub.tex components. Not watching sub.tex for changes & autobuild makes it annoyingly hard to use vscode.

[jlelong]

It sounds like you are using the \subfile package in a non standard way. If you do not intend to ever compile the main.tex file, why not simply putting its preamble in a preamble.tex file and have it included as \input{preamble.tex} in sub.tex`. That would perfectly work and be handled properly by the extension.

[rzach]

Well, I wouldn't say it's a nonstandard way. It's now lost in the mist of time but I think I originally got the idea to use subfiles for this purpose from a stackexchange post, so I'm not alone.

I don't ever compile main.tex but I do compile multiple other files that \subfile the file sub.tex. Basically all my sub.tex are modules that fit into multiple larger projects, but also have to be compiled on their own. I use main.tex to set it up so that they can all be compiled stand-alone. There are hundreds of them, and organized into hierarchical folders, which is part of the reason I use subfiles and not standalone. Because it's so many files and because I have dozens of people working with the files, changing all of them to some other setup is also prohibitive.

Anyway, if it's too hard to just always watch the file in the current editor, I suppose I can just use 8.6.0.

[rzach]

I have another reasons why LaTeX WS should autobuild a subfile on change regardless of whether it's actually \subfile'd in main.tex. I can easily imagine a scenario where I'm working on main.tex but, say, temporarily comment out \subfile{sub} or the \subfile{sub} isn't explicit and is somehow missed by your parsing algorithm. I'd still want to be able to autobuild sub.tex in these cases.

(The project I described, btw, is https://github.com/OpenLogicProject/OpenLogic)