How to find out if a changeset contains another changeset?

[Gilles Moris]

On Wed March 19 2008 14:18:27 Peter Weseloh wrote:
> Hi,
> basically the subject says it already: Is there a simple way in Mercurial to
> find out if a changeset is in the parent list (following merges) of another
> changeset?
> Background is that I have a executable and I know the changeset sha id it
> was build from. Now I want to know if a certain feature/bugfix (from which I
> also know the sha id ) is in the exe. I was able to find this out using 'hg
> view' but due to many branches/merges this was quite complicated.
> With the changesets forming a DAG this question should be simple to answer,
> right? Unfortunately I could not find a command or simple combination of
> commands to do this. Any ideas?
> 
> Thanks in advance,
> Peter
> 

I have also the same question but the other way round: which tags contain a
given changeset ?
Use case: I know that a fix is in a particular changeset (annotate), and I want
to know the first tag on which it was fixed.

Thanks.
Gilles.