--- /dev/null
+Using the Mercurial backend, the lack of `rcs_commit_staged` is noticed frequently. I couldn't find any tries to update `mercurial.pm`, so not letting lack of Mercurial AND Perl knowledge bring me down, I copy-pasted from `git.pm` to mimic its behaviour from a Mercurial perspective. I hope it can be a foundation for development by those more proficient in ikiwiki's inner workings. I have doubts that I personally will be able to revise it more, based on my Perl skills.
+
+I've tested it briefly. `ikiwiki-calendar` and posting of comments now works with automatic commits, i.e. the `rcs_commit_staged` function works in those cases. Under my current setup, I don't know where else to expect it to work. I would be flabberghasted if there wasn't any problems with it, though.
+
+Diff follows, for anyone to annotate. Code is also available at [my hg-repo](http://510x.se/hg/program/ikiwiki/file/e741fcfd800f/Plugin/mercurial.pm).
+
+ diff -r 20c61288d7bd Plugin/mercurial.pm
+ --- a/Plugin/mercurial.pm Fri Jul 15 02:55:12 2011 +0200
+ +++ b/Plugin/mercurial.pm Fri Jul 15 03:29:10 2011 +0200
+ @@ -7,6 +7,8 @@
+ use Encode;
+ use open qw{:utf8 :std};
+
+ +my $hg_dir=undef;
+ +
+ sub import {
+ hook(type => "checkconfig", id => "mercurial", call => \&checkconfig);
+ hook(type => "getsetup", id => "mercurial", call => \&getsetup);
+
+A corresponding variable is declared for git. It is unused as of yet for Mercurial, but when more advanced merge features become available for `mercurial.pm`, I think it will come into play.
+
+ @@ -69,6 +71,62 @@
+ },
+ }
+
+ +sub safe_hg (&@) {
+ + # Start a child process safely without resorting to /bin/sh.
+ + # Returns command output (in list content) or success state
+ + # (in scalar context), or runs the specified data handler.
+ +
+ + my ($error_handler, $data_handler, @cmdline) = @_;
+ +
+ + my $pid = open my $OUT, "-|";
+ +
+ + error("Cannot fork: $!") if !defined $pid;
+ +
+ + if (!$pid) {
+ + # In child.
+ + # hg commands want to be in wc.
+ + if (! defined $hg_dir) {
+ + chdir $config{srcdir}
+ + or error("cannot chdir to $config{srcdir}: $!");
+ + }
+ + else {
+ + chdir $hg_dir
+ + or error("cannot chdir to $hg_dir: $!");
+ + }
+ + exec @cmdline or error("Cannot exec '@cmdline': $!");
+ + }
+ + # In parent.
+ +
+ + # hg output is probably utf-8 encoded, but may contain
+ + # other encodings or invalidly encoded stuff. So do not rely
+ + # on the normal utf-8 IO layer, decode it by hand.
+ + binmode($OUT);
+ +
+ + my @lines;
+ + while (<$OUT>) {
+ + $_=decode_utf8($_, 0);
+ +
+ + chomp;
+ +
+ + if (! defined $data_handler) {
+ + push @lines, $_;
+ + }
+ + else {
+ + last unless $data_handler->($_);
+ + }
+ + }
+ +
+ + close $OUT;
+ +
+ + $error_handler->("'@cmdline' failed: $!") if $? && $error_handler;
+ +
+ + return wantarray ? @lines : ($? == 0);
+ +}
+ +# Convenient wrappers.
+ +sub run_or_die ($@) { safe_hg(\&error, undef, @_) }
+ +sub run_or_cry ($@) { safe_hg(sub { warn @_ }, undef, @_) }
+ +sub run_or_non ($@) { safe_hg(undef, undef, @_) }
+ +
+ sub mercurial_log ($) {
+ my $out = shift;
+ my @infos;
+ @@ -116,10 +174,7 @@
+ }
+
+ sub rcs_update () {
+ - my @cmdline = ("hg", "-q", "-R", "$config{srcdir}", "update");
+ - if (system(@cmdline) != 0) {
+ - warn "'@cmdline' failed: $!";
+ - }
+ + run_or_cry('hg', '-q', 'update');
+ }
+
+ sub rcs_prepedit ($) {
+
+With the `run_or_{die,cry,non}()` functions defined as in `git.pm`, some old Mercurial functions can be rewritten more compactly.
+
+ @@ -129,6 +184,14 @@
+ sub rcs_commit (@) {
+ my %params=@_;
+
+ + return rcs_commit_helper(@_);
+ +}
+ +
+ +sub rcs_commit_helper (@) {
+ + my %params=@_;
+ +
+ + my %env=%ENV;
+ +
+ my $user="Anonymous";
+ if (defined $params{session}) {
+ if (defined $params{session}->param("name")) {
+
+Here comes the `rcs_commit{,_staged}` part. It is modeled on a `rcs_commit_helper` function, as in `git.pm`.
+
+Some old `mercurial.pm` logic concerning commiter name is kept instead of transplanting the more elaborate logic from `git.pm`. Maybe it is better to "steal" that as well.
+
+ @@ -143,43 +206,45 @@
+ $params{message} = "no message given";
+ }
+
+ - my @cmdline = ("hg", "-q", "-R", $config{srcdir}, "commit",
+ - "-m", IkiWiki::possibly_foolish_untaint($params{message}),
+ - "-u", IkiWiki::possibly_foolish_untaint($user));
+ - if (system(@cmdline) != 0) {
+ - warn "'@cmdline' failed: $!";
+ + $params{message} = IkiWiki::possibly_foolish_untaint($params{message});
+ +
+ + my @opts;
+ +
+ + if (exists $params{file}) {
+ + push @opts, '--', $params{file};
+ }
+ -
+ + # hg commit returns non-zero if nothing really changed.
+ + # So we should ignore its exit status (hence run_or_non).
+ + run_or_non('hg', 'commit', '-m', $params{message}, '-q', @opts);
+ +
+ + %ENV=%env;
+ return undef; # success
+ }
+
+ sub rcs_commit_staged (@) {
+ # Commits all staged changes. Changes can be staged using rcs_add,
+ # rcs_remove, and rcs_rename.
+ - my %params=@_;
+ -
+ - error("rcs_commit_staged not implemented for mercurial"); # TODO
+ + return rcs_commit_helper(@_);
+ }
+
+ sub rcs_add ($) {
+ my ($file) = @_;
+
+ - my @cmdline = ("hg", "-q", "-R", "$config{srcdir}", "add", "$config{srcdir}/$file");
+ - if (system(@cmdline) != 0) {
+ - warn "'@cmdline' failed: $!";
+ - }
+ + run_or_cry('hg', 'add', $file);
+ }
+
+ sub rcs_remove ($) {
+ + # Remove file from archive.
+ +
+ my ($file) = @_;
+
+ - error("rcs_remove not implemented for mercurial"); # TODO
+ + run_or_cry('hg', 'remove', '-f', $file);
+ }
+
+ sub rcs_rename ($$) {
+ my ($src, $dest) = @_;
+
+ - error("rcs_rename not implemented for mercurial"); # TODO
+ + run_or_cry('hg', 'rename', '-f', $src, $dest);
+ }
+
+ sub rcs_recentchanges ($) {