pdfplumber 0.5.28 requires pdfminer.six==20200517, but you have pdfminer-six 20211012 which is incompatible

[alexreg]

Describe the bug

Upon running pip install pdfplumber, I get the following.

ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
pdfplumber 0.5.28 requires pdfminer.six==20200517, but you have pdfminer-six 20211012 which is incompatible.

This is an awfully restrictive dependency, that is naturally liable to create conflicts. Perhaps you could loosen it to pdfminer.six>=20200517 (possibly with <= bound too)?

Environment

• pdfplumber version: 0.5.28
• Python version: 3.9.7
• OS: macOS 12.0.1

[jsvine]

Hi @alexreg, and glad to see you around here again! Unfortunately for you, this pinned dependency is intentional and unlikely to change in the immediate future. The main reason is that pdfminer.six, while relatively mature, has introduced breaking changes from time to time, and does not use semantic versioning. Two bits of good news, though:

• pdfplumber will likely work with whatever pdfminer.six version you prefer, so feel free to upgrade the latter. You'll get a conflict warning, but can override/ignore that.

• The next pdfplumber release will upgrade the pinned version of pdfminer.six to the latest.

[alexreg]

@jsvine Thanks for the clarification. That makes sense. Indeed, it's a shame that pdfminer.six doesn't use semver. (Have you tried to convince them to adopt it?)

[jsvine]

I haven't tried lobbying for that, but the maintainers appear to have decided against it — cf.: https://github.com/pdfminer/pdfminer.six/issues/154#issuecomment-576911835

We are not going to use semver (because pypi will get untenable confused).

[alexreg]

Ah, that's a shame, but fair enough. I suppose I'll just ignore the "error" and treat it more like a warning.