How to ignore files/directories in “git archive” and only create an archive of a subdirectory?

Question

TL;DR: The git archive command seems to only either archive a single subdirectory or adhere to .gitattributes and exclude files/directories from the resulting ZIP, but cannot do both.

Say I have this directory structure in my git archive (simplified for reasability):

.
├── assets
├── build
├── CONTRIBUTING.md
├── CONTRIBUTORS
├── LICENSE.md
├── README.md
├── scripts
├── src
│   ├── background
│   ├── common
│   ├── icons
│   ├── _locales
│   ├── manifest.json
│   ├── options
│   ├── popup
│   └── tests
└── tests -> src/tests

Now I want to get an ZIP (or tar) archive with the following content:

• content of src directory only, as this is the source code I want to archive. Without the src directly, itself, however.
• inside of these directories I may want to ignore more folders and files. E.g. tests needs to be ignored, obviously.

So in the end, the archive should e.g. look like that:

.
├── background
├── common
├── icons
├── _locales
├── manifest.json
├── options
└── popup

Now, I thought git archive is a great tool for that. You can archive a subdirectory only and use .gitattributes files with export-ignore to exclude directories and files wherever I want.

The aim is to also use .gitattributes recursively inside multiple subfolders, so I can also always exclude single files from the archive without knowing the upper folder structure. (That's useful for included libraries e.g.)

I also noticed you may need to add the parameter --worktree-attributes so git picks up the .gitattributes files everywhere, where it finds it. And I have use ** to exclude subdirectories. That's fine.

So (for testing here) I tried this:

$ git archive --worktree-attributes --format=tar HEAD:src | tar t

So only archiving the subdirectory works without any problems, but excludes files did not work.

E.g. I put this .gitattributes into the src directory:

tests export-ignore
tests/** export-ignore

Now, running the command mentioned above, it still includes the tests dir content. However, if I run git archive --worktree-attributes --format=tar HEAD | tar t, i.e. not archive the subdirectory, the list ends with:

src/popup/[…]
tests

This means it excludes the content of the tests dir. For some reason, it did not exclude the dir itself, but that may be another issue on my side.

In contrast, if I put the follwing file into the root directory, the whole src/tests dir is excluded (although I had said they semantically mean the same):

src/tests export-ignore
src/tests/** export-ignore

My git version: 2.17.2
Fedora 28

Edit: I noticed now it somehow seems to work when I put the .gitattributes file into the root dir, but mention the file paths relative to the src dir. I.e. doing this (also tested with file exclusion):

tests export-ignore
tests/** export-ignore
manifest.json export-ignore

…somehow makes it work with the src archive command. Now, it does not work with archiving the whole dir anymore (but that is okay). However, if I put this file anywhere else (like in the src dir) it again does not work…

And as my aim is to have .gitattributes files in subdirectories to exclude specific stuff in these directories, this still does not work as expected.