Handling of invalid values in the Search, Search, Replace and Replace methods

[Ekopalypse]

fixes#172

Additional methods such as editor.replaceSel must be handled differently, as these are automatically generated by the iface file.

[chcg]

@Ekopalypse The original "request" was:

I was semi-surprised to see a non-zero result printed.
Any chance that the plugin could trap on this situation and not match anything?

From that point I think your PR is a different approach and notifies the user about "invalid" or "problematic" input.

[Ekopalypse]

@chcg, @sasumner
So PS should return an empty list instead?
What would be the use case for searching for an empty string?

[alankilborn]

Well, nobody asked me, but:

• I suppose an empty list would be fine
• There is no use case for intentionally searching for an empty string (but it could happen unintentionally)

[Ekopalypse]

... but it could happen unintentionally

but the code logic is not aware of this.
In the case of an empty list, this could mean that nothing was found instead of nothing having been searched for. Wouldn't it make more sense to return that nothing was searched for?

[alankilborn]

Wouldn't it make more sense to return that nothing was searched for?

Ah, I see.
The problem is in how to return that.
It appears the PR code creates an exception...

[Ekopalypse]

It appears the PR code creates an exception...

Correct, this PR aims to prohibit empty strings as search arguments and None as search or replace arguments.

[alankilborn]

So, my choices will be, that every search I do after this PR is integrated will need to look like:

iflen(find_text) ==0:
...
else:
editor.research(find_text, ...)

or:

try:
editor.research(...)
except:
...

because we can't have the script user seeing the exception/traceback.

I'm just trying to understand my options. :-)

[Ekopalypse]

I don't understand the question. You can still use editor.research(find_text, ...) without the try or if block, as long as you know the input is valid.
If you're writing a script where someone else is doing the input, you need to check the input anyway, since it's probably based on certain predefined rules, right?
The question that needs to be answered from my point of view is, do we return an empty list with the risk of giving the impression that something was not found even though nothing was searched for or do we throw an exception if the arguments that are expected are empty string or None.

[alankilborn]

I don't understand the question.

No worries; it was simply me rambling. :-)

---

do we return an empty list with the risk of giving the impression that something was not found even though nothing was searched for

No.

or do we throw an exception if the arguments that are expected are empty string or None.

Yes.

[chcg]

@Ekopalypse@alankilborn So we start to go for the exception solution until a reasonable complain is coming up.