Add PHPStan and fix level 1 errors

[mvorisek]

based on tecnickcom/TCPDF#307, conflicts fixed

@williamdes enable phpstan in CI

[codecov]

Codecov Report

Merging #2 (512c978) into main (8703d9f) will increase coverage by 7.46%.
The diff coverage is 59.45%.

@@            Coverage Diff             @@
##             main       #2      +/-   ##
==========================================
+ Coverage   64.59%   72.05%   +7.46%     
==========================================
  Files         115      125      +10     
  Lines       21166    22872    +1706     
==========================================
+ Hits        13672    16481    +2809     
+ Misses       7494     6391    -1103     

Flag	Coverage Δ
php-5.3-ubuntu-latest	71.59% <59.45%> (-28.41%)	⬇️
php-5.4-ubuntu-latest	71.74% <59.45%> (-28.26%)	⬇️
php-5.5-ubuntu-latest	71.75% <59.45%> (-28.25%)	⬇️
php-5.6-ubuntu-latest	46.93% <37.83%> (?)
php-7.1-ubuntu-latest	47.34% <40.90%> (+0.01%)	⬆️
php-7.2-ubuntu-latest	47.29% <40.90%> (+0.01%)	⬆️
php-7.3-ubuntu-latest	47.28% <40.90%> (+0.01%)	⬆️
php-7.4-ubuntu-latest	47.28% <40.90%> (+<0.01%)	⬆️
php-8.0-ubuntu-latest	64.54% <50.00%> (+0.03%)	⬆️

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Impacted Files	Coverage Δ
include/barcodes/qrcode.php	63.72% <33.33%> (+0.16%)	⬆️
tests/coverage.php	17.24% <33.33%> (ø)
tcpdf.php	70.95% <82.35%> (+8.10%)	⬆️
include/barcodes/datamatrix.php	52.23% <100.00%> (-0.09%)	⬇️
include/tcpdf_static.php	54.00% <100.00%> (+5.53%)	⬆️
examples/example_020.php	94.23% <0.00%> (-1.77%)	⬇️
include/barcodes/pdf417.php	59.27% <0.00%> (-1.34%)	⬇️
include/tcpdf_images.php	54.54% <0.00%> (-1.24%)	⬇️
tcpdf_autoconfig.php	46.29% <0.00%> (-0.38%)	⬇️
... and 52 more

---

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[mvorisek]

PHP 7.1 needed also for better syntax, see https://github.com/tecnickcom/TCPDF/pull/300/files#diff-d2ab9925cad7eac58e0ff4cc0d251a937ecf49e4b6bf57f8b95aab76648a9d34R25 , is there any strong reason to not drop support of these historical php versions?

[williamdes]

PHP 7.1 needed also for better syntax, see https://github.com/tecnickcom/TCPDF/pull/300/files#diff-d2ab9925cad7eac58e0ff4cc0d251a937ecf49e4b6bf57f8b95aab76648a9d34R25 , is there any strong reason to not drop support of these historical php versions?

Well, a lof of systems use this lib, and maybe because it is supported for old PHP versions.
Sadly all the world is not ready for PHP 7, maybe more years to wait :/

[mvorisek]

PHP 7.1 needed also for better syntax, see https://github.com/tecnickcom/TCPDF/pull/300/files#diff-d2ab9925cad7eac58e0ff4cc0d251a937ecf49e4b6bf57f8b95aab76648a9d34R25 , is there any strong reason to not drop support of these historical php versions?

Well, a lof of systems use this lib, and maybe because it is supported for old PHP versions.
Sadly all the world is not ready for PHP 7, maybe more years to wait :/

That is correct, but these systems can use original tcpdf :)

[williamdes]

That is correct, but these systems can use original tcpdf :)

This is true and an interesting fact 🤔

[williamdes]

Thank you @mvorisek for your contribution !
I added a bunch of work and cut out in a commit the code removal