provider: three postgismvt InvalidParam calls pass an extra argument, producing %!(EXTRA ...)

[Michad]

Three InvalidParam calls in the postgis mvt provider pass an extra argument, so the startup validation error an operator sees ends in %!(EXTRA ...).

InvalidParam has two verbs, pkg/config/config.go:509:

InvalidParam: "Invalid value supplied for parameter %v: %v",

internal/providers/postgis_mvt.go:91, :96 and :102 each pass three arguments:

return nil, fmt.Errorf(deps.ErrorMessages.InvalidParam, "postgismvt.gid", cfg.GID, columnRegex)

return nil, fmt.Errorf(deps.ErrorMessages.InvalidParam, "postgismvt.geometry", cfg.Geometry, columnRegex)

return nil, fmt.Errorf(deps.ErrorMessages.InvalidParam, "postgismvt.attributes."+strconv.Itoa(i), attribute, columnRegex)

so a bad column name produces:

Invalid value supplied for parameter postgismvt.gid: bad-name%!(EXTRA *regexp.Regexp=^[a-zA-Z0-9_]+$)

The useful part still comes through, it just has formatter noise stapled to the end. go vet's printf check doesn't catch it because the format string is indirected through a struct field rather than being a literal.

I checked every InvalidParam call site in the tree and these three are the only ones that don't pass exactly two arguments. Line 115 in the same file is correct:

return nil, fmt.Errorf(deps.ErrorMessages.InvalidParam, "postgismvt.datastore", cfg.Datastore)

Two ways to resolve it, and the choice is worth a moment's thought rather than defaulting to the smaller diff:

• Drop columnRegex from the three calls. Smallest change, but the operator loses any statement of what the accepted format actually is, and "bad-name" isn't self-explanatory.
• Keep the regex and use a message that has somewhere to put it. Telling the operator the allowed pattern is genuinely more useful for this particular error, since the constraint isn't guessable. That likely means a new entry in ErrorMessages rather than changing InvalidParam, which is shared by ~35 call sites and is part of the config schema operators can localize.

The second is better for the operator but adds a message key, which touches the error message documentation. Either way this is contained to the three lines.