Re: Cleanup shadows variable warnings, round 1

On 28/11/2025 10:16, Chao Li wrote:
> Hi Hackers,
>
> While reviewing [1], it makes me recall an experience where I had a
> patch ready locally, but CommitFest CI failed with a shadows-variable
> warning. Now I understand that -Wall doesn't by default enable -Wshadows
> with some compilers like clang.
>
> I did a clean build with manually enabling -Wshadow and
> surprisingly found there are a lot of such warnings in the current code
> base, roughly ~200 occurrences.
>
> As there are too many, I plan to fix them all in 3-4 rounds. For round 1
> patch, I'd see any objection, then decide if to proceed more rounds.

I don't know if we've agreed on a goal of getting rid of all shadowing,
it's a lot of code churn. I agree shadowing is often confusing and
error-prone, so maybe it's worth it.

On the patch itself:

In some of the cases, I think we should rename the global / outer-scoped
variable instead of the local variable. For example, it's pretty insane
that we apparently have a global variable called 'days'. :-)

Let's think a little harder about the new names. For example:

> @@ -1274,8 +1274,8 @@ execute_extension_script(Oid extensionOid, ExtensionControlFile *control,
> Datum old = t_sql;
> char *reqextname = (char *) lfirst(lc);
> Oid reqschema = lfirst_oid(lc2);
> - char *schemaName = get_namespace_name(reqschema);
> - const char *qSchemaName = quote_identifier(schemaName);
> + char *schemaname = get_namespace_name(reqschema);
> + const char *qSchemaName = quote_identifier(schemaname);
> char *repltoken;
>
> repltoken = psprintf("@extschema:%s@", reqextname);

Having two local variables that only differ in case is also confusing.
We're using the 'req*' prefix here for the other variables, so I think
e.g. 'reqSchemaName' would be a good name here.

(I didn't go through the whole patch, these were just a few things that
caught my eye at quick glance)

- Heikki