cabal version from cabal --version not accepted in field cabal-version

[typetetris]

I expected to be able to put the version number from cabal --version cropped accordingly into the field cabal-version.

$ cabal --version
cabal-install version 3.2.0.0
compiled using version 3.2.0.0 of the Cabal library

and

cabal-version: 3.2

lead to

Errors encountered when parsing cabal file backend/backend.cabal:

backend/backend.cabal:0:0: error:
Unsupported cabal-version. See https://github.com/haskell/cabal/issues/4899.

It seems like only the version numbers in Package Description Format Specification History can be used in field cabal-version.

I would suggest to either note that in the documentation of cabal-version or accept any cabal version number and make cabal know, which version number lower or equal had the last format
change (or whatever else there is to know).

[phadej]

The is no cabal-version: 3.2, see available versions: https://cabal.readthedocs.io/en/3.4/file-format-changelog.html

The confusion steps from cabal having at least three-four meanings https://gist.github.com/merijn/8152d561fb8b011f9313c48d876ceb07

• Cabal the library
• cabal the executable (cabal-install)
• CABAL the spec
• .cabal the package description file

The cabal-version in .cabal files indicates the version of the format of the file, which is CABAL the spec version, though latter haven't been update as a standalone document for ages.

[typetetris]

Yes it is really confusing that the term cabal is overloaded with four meanings.

I read

https://cabal.readthedocs.io/en/3.4/cabal-package.html?highlight=cabal-version#pkg-field-cabal-version

and

https://cabal.readthedocs.io/en/3.4/file-format-changelog.html

and didn't got that.

I guess I am not unique in that.

So maybe add a sentence to the first paragraph in https://cabal.readthedocs.io/en/3.4/cabal-package.html?highlight=cabal-version#pkg-field-cabal-version like

That means you can only choose on of the version listed in [Package Description Format Specification History](https://cabal.readthedocs.io/en/3.4/file-format-changelog.html#package-description-format-specification-history) for this field.

would probably a good idea to help reduce the confusion.

Sorry to bother you, just trying to help.

[typetetris]

Also a link to this CABAL the spec would help. The overloaded meaning of the term cabal makes it really hard to google for that stuff.