Feature or enhancement

Proposal:

This is kind of between a bug and a feature.alias, admittedly a rarely used command, is very unpolished.

The documentation claimed

Replaceable parameters can be indicated by %1, %2, and so on

But that's not the truth,%10 will not work because it contains%1 and we are using pure string replacement. I doubt anyone would need%10 so I just updated the document to imply that we only support up to%9.

All the replaceable parameters should be consecutive as well, if%* does not exist. I can't find one reason where an alias needs parameter 1 and 3, but not 2. (Feel free to show a useful example if you can think of one). We should catch this because it's almost definitely a mistake made by users.

When using alias, we should match all the replaceable parameters and the user input arguments if%* does not exist, otherwise something has to be wrong and we should warn user.

I stepped into this today when I was trying to use alias for some testing:

(Pdb) alias myp p(Pdb) myp 1*** SyntaxError: invalid syntax(Pdb)

Really confusing huh? What if it's

(Pdb) alias myp p(Pdb) myp 1*** Too many arguments for alias 'myp'(Pdb)

It'll probably be easier to track the logic and make you realize that there's no replaceable parameters defined inmyp and it should bealias myp %1.

It's not the most intuitive way but it has been there for a long time. Making the error message better will hopefully make users less confusing.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-111719: Add extra check for alias command #111720