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undo: assert undoability instead of rolling back invalid undo

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Making use of other recent changes, like that it's now safe to throw
exceptions during hook_checkout_prepare to abort the transaction.
This commit is contained in:
Juerd Waalboer 2023-12-26 02:10:34 +01:00
parent 6b04ecc256
commit f4d3b7fd5c
2 changed files with 33 additions and 54 deletions
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9
plugins/statiegeld_tokens
View file

@ -115,7 +115,7 @@ sub _warn($message) {
warn "\e[31;1mSorry,\e[0m $message\n";
}
sub _handle_undo($cart) {
sub hook_undo($class, $cart) {
# Undoing properly is hard. We can easily void tokens, but we can't restore
# them. That would requires duplicating all of the undo logic that exists
# for account balances, but for tokens. Too much work for something that I
@ -127,10 +127,13 @@ sub _handle_undo($cart) {
next if $contra->{amount} < 0;
next if List::Util::none { $contra->{user} eq $_ } _addon_accounts;
_warn "deposit refunds cannot be undone.";
die "ROLLBACK_UNDO";
return ABORT, "Sorry, deposit refunds cannot be undone.";
}
}
}
sub _handle_undo($cart) {
for my $entry ($cart->entries) {
# Undo buying: void specific tokens
my $undo_tid = $entry->attribute('undo_transaction_id')
or die "Plugin error: broken '-undo' transaction";

78
plugins/undo
View file

@ -6,11 +6,6 @@ my $filename = ".revbank.undo";
my @TAB;
{
package RevBank::Plugin::undo::RollBackUndo;
sub new($class) { return bless [], $class; }
}
sub command :Tab(undo) ($self, $cart, $command, @) {
$command eq 'undo' or return NEXT;
@ -43,7 +38,7 @@ sub command :Tab(undo) ($self, $cart, $command, @) {
sub tab { @TAB }
my $doing_undo = 0; # Ugly but works, just like the rest of this plugin
our $doing_undo = 0; # Ugly but works, just like the rest of this plugin
sub undo :Tab(&tab) ($self, $cart, $tid, @) {
my $description = "Undo $tid";
@ -51,13 +46,8 @@ sub undo :Tab(&tab) ($self, $cart, $tid, @) {
my $found = 0;
my $aborted = 0;
with_lock {
my $backup = "$filename.bak.$$";
spurt $backup, slurp $filename; # copy for rollback
# Immediately remove from file, to avoid double undo when something
# crashes.
rewrite $filename, sub($line) {
return with_lock {
for my $line (slurp $filename) {
if ($line =~ /^\Q$tid\E\s/) {
my (undef, $user, $delta) = split " ", $line;
@ -65,49 +55,35 @@ sub undo :Tab(&tab) ($self, $cart, $tid, @) {
$entry->{FORCE_UNBALANCED} = 1;
$entry->add_contra($user, $delta, "Undo $tid");
}
}
$cart->size or return ABORT, "Transaction ID '$tid' not found in undo log.";
call_hooks("undo", $cart) or return ABORT;
local $doing_undo = 1; # don't allow undoing undos
$cart->checkout('-undo');
return ACCEPT;
};
}
sub hook_checkout_prepare($class, $cart, $username, $transaction_id, @) {
$username eq '-undo' or return;
for my $entry ($cart->entries) {
my $undo_tid = $entry->attribute('undo_transaction_id')
or die "Plugin error: broken '-undo' transaction";
rewrite $filename, sub($line) {
if ($line =~ /^\Q$undo_tid\E\s/) {
return undef; # remove line
} else {
return $line;
}
};
if ($cart->size) {
$found = 1;
$doing_undo = 1; # don't allow undoing undos
eval { $cart->checkout('-undo') };
if ($@ isa RevBank::Plugin::undo::RollbackUndo) {
# Undo the undo... :)
spurt $filename, slurp $backup;
# can't 'return ABORT' here; it would return from with_lock
$aborted = 1;
} elsif ($@ isa RevBank::Cart::CheckoutProhibited) {
my $reason = $@->reason;
# Undo the undo... :)
spurt $filename, slurp $backup;
$aborted = 1;
warn "$reason\n";
} elsif ($@ and ref $@) {
# Re-throw exception object
die $@;
} elsif ($@) {
# Re-throw exception string
die "(undo file BACKUP at $backup.)\n$@";
} else {
unlink $backup;
}
$doing_undo = 0;
}
};
return ABORT, "Undo prohibited." if $aborted;
return ACCEPT if $found;
return ABORT, "Transaction ID '$tid' not found in undo log.";
}
}
sub hook_user_balance($class, $username, $old, $delta, $new, $transaction_id, @) {