How to copy `docfiles` with directory structure respected?

For large doc target, its supplement files may live in sub-directories like ./image, ./chapters. Currently when specified as docfiles = { "image/*.jpg", "chapters/*.tex" }, the matched files will be copied directly to typesetdir, with a flat directory structure.

This will break usages like \include{chapters/chap01.tex} in doc file. Although this use case can be resolved by appending chapters to \input@path or \l_file_search_path_seq and removing path prefix chapter/, some \input-derived package macros may not respect \input@path yet, among which pgf's \pgfutil@IfFileExists is an example, see #1238.

In https://github.com/pgf-tikz/pgf/pull/1239#discussion_r1103711874 I found specifying just directory names in docfiles seems to work, for example docfiles = { "image", "chapter" }, but not sure if this is officially supported.

Taking ./examples/Simple-Tree in this repository as an example

First, create dummy files `./doc/images/a.jpg` and `./doc/images/b.jpg` ``` mkdir doc/images touch doc/images/a.jpg doc/images/b.jpg ``` Now the structure of `./doc` becomes ``` doc ├── images │ ├── a.jpg │ └── b.jpg ├── simple-tree-doc.pdf ├── simple-tree-doc.tex └── simple-tree.pdf ``` - If `docfiles = { "images/*.jpg" }` is appended to `build.lua` ``` echo 'docfiles = { "images/*.jpg" }' >> build.lua ``` then after `l3build doc` the structure of `./build/doc` will be ``` build/doc ├── a.jpg ├── b.jpg ├── simple-tree-doc.aux ├── simple-tree-doc.log ├── simple-tree-doc.pdf ├── simple-tree-doc.tex ├── simple-tree.aux └── ... ``` - If instead `docfiles = { "images" }` is appended to `build.lua` ``` echo 'docfiles = { "images" }' >> build.lua ``` then after `l3build doc` the structure of `./build/doc` will be ``` build/doc ├── images │ ├── a.jpg │ └── b.jpg ├── simple-tree-doc.aux ├── simple-tree-doc.log ├── simple-tree-doc.pdf ├── simple-tree-doc.tex ├── simple-tree.aux └── ... ```

latex3 / l3build

How to copy `docfiles` with directory structure respected? #331