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Return the libpq default port when blank in conninfo#492

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larskanis merged 3 commits into
ged:masterfrom
cbandy:port-integer
Nov 17, 2022
Merged

Return the libpq default port when blank in conninfo#492
larskanis merged 3 commits into
ged:masterfrom
cbandy:port-integer

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@cbandy

@cbandy cbandy commented Nov 12, 2022

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This is one potential fix for #491.

Internally, libpq checks for null or empty string stored in pg_conn_host and falls back to the configured default --with-pgport. This does the same for our wrapper around PQport.

	/*
	 * Next, work out the port number corresponding to each host name.
	 *
	 * Note: unlike the above for host names, this could leave the port fields
	 * as null or empty strings.  We will substitute DEF_PGPORT whenever we
	 * read such a port field.
	 */
		/* Figure out the port number we're going to use. */
		if (ch->port == NULL || ch->port[0] == '\0')
			thisport = DEF_PGPORT;

It has done this for a long time:

@cbandy
Return the libpq default port when blank in conninfo
68d40c5 
PQport may return null or empty string when the same is set in
connection options. Internally, libpq falls back to its configured
default any time it reads these.
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ged reviewed Nov 14, 2022
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Do you think it's worth adding tests for this?

@cbandy

cbandy commented Nov 15, 2022

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I tried, though only briefly. The suite is set up to start a local Postgres on a high port, but this code path requires a working connection on the default port.

@larskanis

larskanis commented Nov 15, 2022

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My first thought was to follow libpq closely and return nil in this special case. But on the other hand it doesn't make much sense to handle this case specially at all. So I wonder why libpq doesn't return a valid port number in any case. It just increases complexity to handle null and empty port on the user side.

So IMHO this PR is OK how it is. I added a test checking the both port return variations.

@larskanis

larskanis commented Nov 15, 2022

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Should we add DEF_PGPORT to PG::Constants?

@ged

ged commented Nov 15, 2022

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@larskanis Yeah, probably. Nice work on the test btw. Those helpers are awesome.

cbandy
cbandy commented Nov 17, 2022
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Comment thread spec/pg/connection_spec.rb Outdated
@larskanis larskanis merged commit 574ecad into ged:master Nov 17, 2022
@larskanis larskanis mentioned this pull request Nov 17, 2022
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@cbandy cbandy deleted the port-integer branch November 18, 2022 00:25
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@cbandy @larskanis @ged