Issues with envelopesender and empty log messages using contrib/hooks/post-receive-email

I've recently encountered 2 problems with use of the example post-receive-mail script in contrib/hooks/post-receive-email.

Firstly I found that having set hooks.envelopesender, the script ended up sending mail with the envelope sender set to the email address given literally surrounded by single quotes which caused the mail server to complain about invalid address syntax.

The offending lines appears to be - 

if [ -n "$envelopesender" ]; then
   envelopesender="-f '$envelopesender'"
fi

which when replaced with 

if [ -n "$envelopesender" ]; then
   envelopesender="-f \"$envelopesender\""
fi

have the desired effect of the script using the unaltered envelope sender when sending mail as set in hooks.envelopesender. I have attached a diff to this effect.

The second problem is that when using a branch that is derived from master, has some differences, but regularly has master merged into it to keep it up to date. If one makes some changes to master, merges these into the other branch, then pushes these to the repository with the mail hook, the email regarding the changes to master has an empty log message.

The relevant lines seem to be in generate_update_branch_email(), line 380 -

git rev-parse --not --branches | grep -v $(git rev-parse $refname) | git rev-list --pretty --stdin $oldrev..$newrev

I understand git-rev-parse will return the negation of the heads of boths branches (master and the other branch) and then the master branch negation is grep outed. However that leaves essentially the command -

git rev-list --pretty --stdin $oldrev..$newrev ^$otherbranchhead

which when $oldrev and $newrev are in the other branch as well seems to result in an empty list / no result as nothing before $otherbranchhead should be shown, and $oldrev and $newrev are both before $otherbranchhead in the stated case but have never been shown in any mails.

Steps to reproduce :

1) Create a repository (repo1) with just the master branch and make
some commits.  
2) Copy contrib/hooks/post-receive-email to [.git/]hooks/post-receive
and chmod +x it.  
3) Create a branch (testbranch) in repo1 
4) Clone repo1 creating repo2 
5) Checkout repo1/testbranch in repo2 
6) Make some commits to testbranch in repo2 
7) Push from repo2 to repo1 
8) Make some commits in repo2/master 
9) Merge repo2/master into repo2/testbranch 
10) Push repo2 to repo1 
11) Notice an empty log message for the mail detailing changes to
master.

If I have misunderstood some key concepts rather than there being bugs here, I apologise in advance, and would just like to know what stupid thing I've done :)

Matthew Gwynne