A follow-on activity to PR #5061. That PR added scrollbars to the dropdown lists when samples were run in a browser. Earlier changes had broken up a number of categories into multiple entries because the dropdown lists were too long and wound up truncated. With the scrollbars, it makes sense to re-consolidate many of those lists, such as ComplexNumbers, which are all essentially the same test as each other. Some break-ups are retained (e.g. Basic/1/2/3/4/5) because they differ substantially from sample to sample; that's kind of an arbitrary decision, but it will have to do for now. I also renamed some of the members so that like members sort together when listing the directory (e.g. all pivot table samples now start with `pvt`). The sample code is mostly unchanged; only the directory and/or member names are changed.
The download samples were moved to their own new directory, and now represent a complete set of all the write formats that we permit. Studying their code, an improvement for `Helper\Downloader` became evident. It had been used merely to copy an existing file to be downloaded. However, by changing the first parameter of `download` to be either the name of the file directory (the existing usage) *or* a `Writer` object poised to issue `save`, you can use it to download your spreadsheet without having to worry about the headers which the browser requires. It then becomes generally useful beyond being used in samples:
```php
$writer = new WriterType($spreadsheet);
$downloader = new Downloader($writer, 'suggestedFileName.xlsx');
$downloader->download();
```
The samples have become unwieldy when running them from a browser. In particular, the drop-down lists are fixed size with no scrolling, and many of them are now just too large. I have moved all the Calculation samples up a level, and broken several categories (Basic, Chart, DateTime, Engineering, Financial, and Reader) into several pieces.
Convert-Online (now found in the Engineering category) had a number of different problems which are now resolved. It is the only member with any significant code change.
* Let Phpstan Run on Samples
Phpstan currently analyzes all source and test members. We already run phpcs and php-cs-fixer on samples as well. I would expect that samples are often used as templates for code in userland; it behooves us to be at least as careful with those members as for the others which are already being analyzed. Aside from 1300+ messages `Variable $helper might not be defined.`, which will be suppressed in phpstan.neon.dist, there are really only a few changes needed for sample members, so that part of the code base was already in good shape, and is now even better. No annotations were needed.
* Scrutinizer 2 out of 3
1 false positive, now suppressed; fix other 2.
* Remove Dead Code
* Very Minor Changes
* Add infra
Because they tend to clutter our code a lot and unfortunately, there are
lots of false positives. Instead, it would probably be better to deal
with false positives out of band, via the Scrutinizer web UI.
oleibman
Adrien Crivelli
Jon Dufresne
yuzhakov