`qrcode` 8.0 requires more work for simplest use case

[williamjacksn]

This works with qrcode 7.4.2.

# pip install qrcode==7.4.2
Collecting qrcode==7.4.2
  Downloading qrcode-7.4.2-py3-none-any.whl.metadata (17 kB)
Collecting typing-extensions (from qrcode==7.4.2)
  Downloading typing_extensions-4.12.2-py3-none-any.whl.metadata (3.0 kB)
Collecting pypng (from qrcode==7.4.2)
  Downloading pypng-0.20220715.0-py3-none-any.whl.metadata (13 kB)
Downloading qrcode-7.4.2-py3-none-any.whl (46 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 46.2/46.2 kB 765.6 kB/s eta 0:00:00
Downloading pypng-0.20220715.0-py3-none-any.whl (58 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 58.1/58.1 kB 3.6 MB/s eta 0:00:00
Downloading typing_extensions-4.12.2-py3-none-any.whl (37 kB)
Installing collected packages: pypng, typing-extensions, qrcode
Successfully installed pypng-0.20220715.0 qrcode-7.4.2 typing-extensions-4.12.2

# qr test > test.png

# file test.png
test.png: PNG image data, 290 x 290, 1-bit grayscale, non-interlaced

But with qrcode 8.0, pypng is no longer automatically installed as a dependency.

# pip install qrcode==8.0
Collecting qrcode==8.0
  Downloading qrcode-8.0-py3-none-any.whl.metadata (17 kB)
Downloading qrcode-8.0-py3-none-any.whl (45 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 45.7/45.7 kB 864.8 kB/s eta 0:00:00
Installing collected packages: qrcode
Successfully installed qrcode-8.0

# qr test > test.png
Traceback (most recent call last):
  File "/usr/local/bin/qr", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/usr/local/lib/python3.12/site-packages/qrcode/console_scripts.py", line 137, in main
    img = qr.make_image(**kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/qrcode/main.py", line 363, in make_image
    from qrcode.image.pil import Image, PilImage
  File "/usr/local/lib/python3.12/site-packages/qrcode/image/pil.py", line 2, in <module>
    from PIL import Image, ImageDraw
ModuleNotFoundError: No module named 'PIL'

Even when pypng is installed, the qr command defaults to the pil factory.

# pip install qrcode[png]
Collecting qrcode[png]
  Downloading qrcode-8.0-py3-none-any.whl.metadata (17 kB)
Collecting pypng (from qrcode[png])
  Downloading pypng-0.20220715.0-py3-none-any.whl.metadata (13 kB)
Downloading pypng-0.20220715.0-py3-none-any.whl (58 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 58.1/58.1 kB 1.0 MB/s eta 0:00:00
Downloading qrcode-8.0-py3-none-any.whl (45 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 45.7/45.7 kB 2.1 MB/s eta 0:00:00
Installing collected packages: pypng, qrcode
Successfully installed pypng-0.20220715.0 qrcode-8.0

# qr test > test.png
Traceback (most recent call last):
  File "/usr/local/bin/qr", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/usr/local/lib/python3.12/site-packages/qrcode/console_scripts.py", line 137, in main
    img = qr.make_image(**kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/qrcode/main.py", line 363, in make_image
    from qrcode.image.pil import Image, PilImage
  File "/usr/local/lib/python3.12/site-packages/qrcode/image/pil.py", line 2, in <module>
    from PIL import Image, ImageDraw
ModuleNotFoundError: No module named 'PIL'

# qr --factory=png test > test.png

# file test.png
test.png: PNG image data, 290 x 290, 1-bit grayscale, non-interlaced

[maribedran]

Thanks for noting this, @williamjacksn! We need to update the docs to make this clear. Since PNG is also an optional dependency, I think the fallback should be SVG, since it doesn't depend on any extra libraries.

[bartTC]

Refs #338

[ofer-pd]

I just learned about and installed qrcode for the first time, and ran into exactly this surprise.

At this point I had only read the first part of the README — "Usage" — which gave me the impression I could run qrcode.make( "foo" ) or $ qr "foo" > test.png immediately after install.

After seeing the ModuleNotFoundError, I explicitly installed pypng, but it still kept trying to use PIL.

Only after that did I revisit the README and discover the "Pure Python PNG" section, which worked.