update-check: download each url once

[Chocimier]

Speed up for packages with multiple downloads from same location or having homepage and distfiles at gitlab or github.

[Gottox]

Not sure that works:

$ a="Hello"
$ a="$a\nWorld"
$ echo "$a"
Hello\nWorld

There's a bashism for that:

$ a="Hello"
$ a="$a"$'\n'"World"
$ echo "$a"
Hello
World

But not sure if we want that. Opinions?

[Chocimier]

Happens to work because variable is used with printf, not echo, but it will break on % in url.

What about literal newline and echo?

        fetchedurls="$fetchedurls
$url"
echo "$fetchedurls" | …

[Gottox]

printf is actually a good idea:

$ a=$(print "%s\n%s" "$a" "$b")

[maxice8]

ping

[Chocimier]

pong

[pullmoll]

I just now stumbled across this PR. Since xbps-src expects bash I think you could simplify the code by using an associative array of URLs. Something along the lines:

local -A fetchedurls
…
        if [ "${fechedurls[$url]}" = "ok" ]; then
            if [ -n "$XBPS_UPDATE_CHECK_VERBOSE" ]; then
                echo "already fetched $url" 1>&2
            fi
            continue
        fi
        …
        fetchedurls[$url]="ok"

You could this way even store an error state (e.g. bad domain name, non-transient resolver error) and report that on a second try for the same $url.

[Chocimier]

Agreed, associative array is good idea here. However as errors aren't printed on first try, printing on second try would be strange.