RFR: 1859: Add "tags only" option to MirrorBot [v2]

[Erik Helin]

On Tue, 28 Mar 2023 22:07:39 GMT, Zhao Song <zsong at openjdk.org> wrote:

>> Erik Helin has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Reviewer feeback
>
> bots/mirror/src/main/java/org/openjdk/skara/bots/mirror/MirrorBotFactory.java line 95:
> 
>> 93:             if (onlyTags && !branchPatterns.isEmpty()) {
>> 94:                 throw new IllegalStateException("Branches cannot be mirrored when only tags are mirrored");
>> 95:             }
> 
> Originally, if `branchPatterns.isEmpty()`, `includeTags` would always be true. But now, it is possible that when `branchPatterns.isEmpty()`, `includeTags` is false.
> So I think we could also throw exception when `branchPatterns.isEmpty() && !includeTags`. It is illegal.

Thanks @zhaosongzs , I reworked this a bit in the latest version and fixed this as well

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PR Review Comment: https://git.openjdk.org/skara/pull/1493#discussion_r1151806810