hgeditor

Deal with failed clone/transaction interaction

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Deal with failed clone/transaction interaction

> What is happening is that something in the transaction machinery is
> causing the directory to be completely recreated.

The transaction gets rolled back by its destructor. This is critical
so it happens whenever an exception occurs that unwinds the stack.

Unfortunately, what's happening with clone is we're trying to delete
the directory during exception propagation. And a reference to the
transaction is held in the exception backtrace stack frames so it
still exists until the exception is completely resolved.

So there's no way to do the directory delete inside the exception
handling cleanly.

But we can handle it similarly to the transaction itself: use an
object with a destructor.

manifest hash: fc38550a20d64d08333f256bbedc312493c1390b
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.0 (GNU/Linux)

iD8DBQFCxDT2ywK+sNU5EO8RAjikAJ0Tej56rAutxQDfYzVbFGtT1sEC5ACgmVds
/fwdQyHn+FwshugqXLemUaM=
=3f78
-----END PGP SIGNATURE-----

#!/bin/bash
#
# This is an example of using HGEDITOR to automate the signing of
# commits and so on.

T1=""; T2=""
cleanup_exit() {
    rm -f "$T1" "$T2"
    exit $1
}

case "${EDITOR:=vi}" in
    emacs)
        EDITOR="$EDITOR -nw"
        ;;
    gvim|vim)
        EDITOR="$EDITOR -f -o"
        ;;
esac

if grep -q "^HG: merge resolve" "$1" ; then
    # we don't sign merges
    exec $EDITOR "$1"
else
    T1=`mktemp`; T2=`mktemp`
    MANIFEST=`grep '^HG: manifest hash' "$1" | cut -b 19-`

    echo -e "\n\nmanifest hash: $MANIFEST" >> "$T1"
    grep -vE '^(HG: manifest hash .*)?$' "$1" >> "$T1"
    (
        cd "`hg root`"
        grep '^HG: changed' "$1" | cut -b 13- | while read changed; do
            hg diff "$changed" >> "$T2"
        done
    )

    CHECKSUM=`md5sum "$T1"`
    $EDITOR "$T1" "$T2" || cleanup_exit $?
    echo "$CHECKSUM" | md5sum -c 2>/dev/null && cleanup_exit 0
    {
        head -1 "$T1"
        echo
        grep -v "^HG:" "$T1" | gpg -a -u "${HGUSER:-$EMAIL}" --clearsign
    } > "$T2" && mv "$T2" "$1"
    cleanup_exit $?
fi