Comment 0 for bug 2045562

Debian source format 1.0 cannot remove files, create symlinks and change
permission in the .diff.gz tarball. Therefore any changes in these 3
categories cannot be represented without any tricks. To solve this,
the `reconstruct` script is used every time we build the source package.
The script is generated by `gen-auto-reconstruct` script during `cranky
close`. It checks if there has been any changes in the 3 categories
mentioned above between the upstream version (i.e v6.5) and the current one.
The problem with the script is that in case a file A was removed since the
upstream version was released, the `reconstruct` script will contains
these commands in this exact order:
        rm -f A
        chmod -x A
The second command will fail because file A does not exist anymore.
This is solved by generating the `chmod +/-x` commands before `rm`.
Which results in:
        chmod -x A
        rm -f A
But because the reconstruct script is used during `clean` rule which is
triggered pretty much during every cranky step which is run in the
source repo, the first command will always file because file A is not
present anymore in the tree. To solved this, any `chmod` change is added
only if the file has not been deleted. Therefore if file A has been
deleted, the `reconstruct` script will contain only this:
        rm -f A

Note: an example of this is #lp