How pre- are pre-render scripts?

[andrewpbray]

When you run quarto render, what operations are done before the pre-render script is run? I had a pre-render script that changed file paths but on render it errored out because it couldn't find the files at the original paths. That suggests it compiles the list of files to render before running the pre-render script - is that correct?

[mcanouil]

You need to actually write something, as is it is merely a post and mostly a spam ...

[cscheid]

I agree with @mcanouil that a bit more information would be helpful :) but I think I can attempt to reverse-engineer the question as "when exactly do quarto pre-render scripts get called?"

The short answer to that is "after determining which files are to be rendered, but before rendering any of them". The long answer to that is "the full story is on src/command/render/project.ts:renderProject"

[Nenuial]

I noticed this order, on my website 😪
I have a pre-render that creates a listing, but the first rendering failed because Quarto detected/checked before the file was created.

I have encountered similar issues when using pre-render to setup files on a website for rendering. Two runs of render solve it, but a better way would actually be great!

[osaal]

Maybe. This kind of ordering issue is finicky so I don't want to make a change without talking to the rest of the team. I'll get back to you.

Sorry to return to an old discussion, but has this been considered by the team for a future update?

I have a similar issue, where I wish to change the project file structure before render (as a solution to having source files in their own subdirectory structure, but rendering a website project output that uses a "flattened" structure without the subdirectories). Since the pre-render scripts are ran after finding the files to render (as seen in src/command/render/project.ts:renderProject), my current solution is to manually run a script prior to calling quarto render.

Would it be possible to implement a way to run pre-render scripts before Quarto finds the project files to be rendered, or alternatively to suppress erroring on "File not found" in the pre-pre-render part of the render process?

Thanks in advance!
Oliver S.

[mcanouil]

This thread is outdated.
What version of Quarto are you using as this should not even be an issue since quite some time now.

[osaal]

This thread is outdated. What version of Quarto are you using as this should not even be an issue since quite some time now.

My apologies. I'm using version 1.6.39. I'll make a separate issue about the problem!

[mcanouil]

To be clear, pre-render script can create new document that are discovered by Quarto which was not possible at the time of this thread.
Quarto now runs a second discovery after pre-render.

If you don't see this, please open a separate GitHub discussion with a small reproducible example as described in the guidelines when opening a GitHub Discussion.

[baptiste]

Another use-case scenario I've run into: I have a R script that generates .qmd files programmatically (each qmd corresponds to a different photo album page for a website); I'm currently running the R script manually before calling quarto render, but ideally this would be taken care of by a pre-render step. At the moment the newly-created .qmd files would be ignored by quarto.

[mcanouil]

Exactly what I described and why I asked if the pre-render could be before file checks (see #3879 (reply in thread)). 😉