Squashed 'third_party/git/' content from commit cb71568594

git-subtree-dir: third_party/git
git-subtree-split: cb715685942260375e1eb8153b0768a376e4ece7

1 files changed, 1374 insertions, 0 deletions

diff --git a/contrib/mw-to-git/git-remote-mediawiki.perl b/contrib/mw-to-git/git-remote-mediawiki.perl
new file mode 100755
index 000000000000..af9cbc9d0f7b
--- /dev/null
+++ b/contrib/mw-to-git/git-remote-mediawiki.perl
@@ -0,0 +1,1374 @@
+#! /usr/bin/perl
+
+# Copyright (C) 2011
+#     Jérémie Nikaes <jeremie.nikaes@ensimag.imag.fr>
+#     Arnaud Lacurie <arnaud.lacurie@ensimag.imag.fr>
+#     Claire Fousse <claire.fousse@ensimag.imag.fr>
+#     David Amouyal <david.amouyal@ensimag.imag.fr>
+#     Matthieu Moy <matthieu.moy@grenoble-inp.fr>
+# License: GPL v2 or later
+
+# Gateway between Git and MediaWiki.
+# Documentation & bugtracker: https://github.com/moy/Git-Mediawiki/
+
+use strict;
+use MediaWiki::API;
+use Git;
+use Git::Mediawiki qw(clean_filename smudge_filename connect_maybe
+					EMPTY HTTP_CODE_OK);
+use DateTime::Format::ISO8601;
+use warnings;
+
+# By default, use UTF-8 to communicate with Git and the user
+binmode STDERR, ':encoding(UTF-8)';
+binmode STDOUT, ':encoding(UTF-8)';
+
+use URI::Escape;
+
+# It's not always possible to delete pages (may require some
+# privileges). Deleted pages are replaced with this content.
+use constant DELETED_CONTENT => "[[Category:Deleted]]\n";
+
+# It's not possible to create empty pages. New empty files in Git are
+# sent with this content instead.
+use constant EMPTY_CONTENT => "<!-- empty page -->\n";
+
+# used to reflect file creation or deletion in diff.
+use constant NULL_SHA1 => '0000000000000000000000000000000000000000';
+
+# Used on Git's side to reflect empty edit messages on the wiki
+use constant EMPTY_MESSAGE => '*Empty MediaWiki Message*';
+
+# Number of pages taken into account at once in submodule get_mw_page_list
+use constant SLICE_SIZE => 50;
+
+# Number of linked mediafile to get at once in get_linked_mediafiles
+# The query is split in small batches because of the MW API limit of
+# the number of links to be returned (500 links max).
+use constant BATCH_SIZE => 10;
+
+if (@ARGV != 2) {
+	exit_error_usage();
+}
+
+my $remotename = $ARGV[0];
+my $url = $ARGV[1];
+
+# Accept both space-separated and multiple keys in config file.
+# Spaces should be written as _ anyway because we'll use chomp.
+my @tracked_pages = split(/[ \n]/, run_git("config --get-all remote.${remotename}.pages"));
+chomp(@tracked_pages);
+
+# Just like @tracked_pages, but for MediaWiki categories.
+my @tracked_categories = split(/[ \n]/, run_git("config --get-all remote.${remotename}.categories"));
+chomp(@tracked_categories);
+
+# Just like @tracked_categories, but for MediaWiki namespaces.
+my @tracked_namespaces = split(/[ \n]/, run_git("config --get-all remote.${remotename}.namespaces"));
+for (@tracked_namespaces) { s/_/ /g; }
+chomp(@tracked_namespaces);
+
+# Import media files on pull
+my $import_media = run_git("config --get --bool remote.${remotename}.mediaimport");
+chomp($import_media);
+$import_media = ($import_media eq 'true');
+
+# Export media files on push
+my $export_media = run_git("config --get --bool remote.${remotename}.mediaexport");
+chomp($export_media);
+$export_media = !($export_media eq 'false');
+
+my $wiki_login = run_git("config --get remote.${remotename}.mwLogin");
+# Note: mwPassword is discourraged. Use the credential system instead.
+my $wiki_passwd = run_git("config --get remote.${remotename}.mwPassword");
+my $wiki_domain = run_git("config --get remote.${remotename}.mwDomain");
+chomp($wiki_login);
+chomp($wiki_passwd);
+chomp($wiki_domain);
+
+# Import only last revisions (both for clone and fetch)
+my $shallow_import = run_git("config --get --bool remote.${remotename}.shallow");
+chomp($shallow_import);
+$shallow_import = ($shallow_import eq 'true');
+
+# Fetch (clone and pull) by revisions instead of by pages. This behavior
+# is more efficient when we have a wiki with lots of pages and we fetch
+# the revisions quite often so that they concern only few pages.
+# Possible values:
+# - by_rev: perform one query per new revision on the remote wiki
+# - by_page: query each tracked page for new revision
+my $fetch_strategy = run_git("config --get remote.${remotename}.fetchStrategy");
+if (!$fetch_strategy) {
+	$fetch_strategy = run_git('config --get mediawiki.fetchStrategy');
+}
+chomp($fetch_strategy);
+if (!$fetch_strategy) {
+	$fetch_strategy = 'by_page';
+}
+
+# Remember the timestamp corresponding to a revision id.
+my %basetimestamps;
+
+# Dumb push: don't update notes and mediawiki ref to reflect the last push.
+#
+# Configurable with mediawiki.dumbPush, or per-remote with
+# remote.<remotename>.dumbPush.
+#
+# This means the user will have to re-import the just-pushed
+# revisions. On the other hand, this means that the Git revisions
+# corresponding to MediaWiki revisions are all imported from the wiki,
+# regardless of whether they were initially created in Git or from the
+# web interface, hence all users will get the same history (i.e. if
+# the push from Git to MediaWiki loses some information, everybody
+# will get the history with information lost). If the import is
+# deterministic, this means everybody gets the same sha1 for each
+# MediaWiki revision.
+my $dumb_push = run_git("config --get --bool remote.${remotename}.dumbPush");
+if (!$dumb_push) {
+	$dumb_push = run_git('config --get --bool mediawiki.dumbPush');
+}
+chomp($dumb_push);
+$dumb_push = ($dumb_push eq 'true');
+
+my $wiki_name = $url;
+$wiki_name =~ s{[^/]*://}{};
+# If URL is like http://user:password@example.com/, we clearly don't
+# want the password in $wiki_name. While we're there, also remove user
+# and '@' sign, to avoid author like MWUser@HTTPUser@host.com
+$wiki_name =~ s/^.*@//;
+
+# Commands parser
+while (<STDIN>) {
+	chomp;
+
+	if (!parse_command($_)) {
+		last;
+	}
+
+	BEGIN { $| = 1 } # flush STDOUT, to make sure the previous
+			 # command is fully processed.
+}
+
+########################## Functions ##############################
+
+## error handling
+sub exit_error_usage {
+	die "ERROR: git-remote-mediawiki module was not called with a correct number of\n" .
+	    "parameters\n" .
+	    "You may obtain this error because you attempted to run the git-remote-mediawiki\n" .
+            "module directly.\n" .
+	    "This module can be used the following way:\n" .
+	    "\tgit clone mediawiki://<address of a mediawiki>\n" .
+	    "Then, use git commit, push and pull as with every normal git repository.\n";
+}
+
+sub parse_command {
+	my ($line) = @_;
+	my @cmd = split(/ /, $line);
+	if (!defined $cmd[0]) {
+		return 0;
+	}
+	if ($cmd[0] eq 'capabilities') {
+		die("Too many arguments for capabilities\n")
+		    if (defined($cmd[1]));
+		mw_capabilities();
+	} elsif ($cmd[0] eq 'list') {
+		die("Too many arguments for list\n") if (defined($cmd[2]));
+		mw_list($cmd[1]);
+	} elsif ($cmd[0] eq 'import') {
+		die("Invalid argument for import\n")
+		    if ($cmd[1] eq EMPTY);
+		die("Too many arguments for import\n")
+		    if (defined($cmd[2]));
+		mw_import($cmd[1]);
+	} elsif ($cmd[0] eq 'option') {
+		die("Invalid arguments for option\n")
+		    if ($cmd[1] eq EMPTY || $cmd[2] eq EMPTY);
+		die("Too many arguments for option\n")
+		    if (defined($cmd[3]));
+		mw_option($cmd[1],$cmd[2]);
+	} elsif ($cmd[0] eq 'push') {
+		mw_push($cmd[1]);
+	} else {
+		print {*STDERR} "Unknown command. Aborting...\n";
+		return 0;
+	}
+	return 1;
+}
+
+# MediaWiki API instance, created lazily.
+my $mediawiki;
+
+sub fatal_mw_error {
+	my $action = shift;
+	print STDERR "fatal: could not $action.\n";
+	print STDERR "fatal: '$url' does not appear to be a mediawiki\n";
+	if ($url =~ /^https/) {
+		print STDERR "fatal: make sure '$url/api.php' is a valid page\n";
+		print STDERR "fatal: and the SSL certificate is correct.\n";
+	} else {
+		print STDERR "fatal: make sure '$url/api.php' is a valid page.\n";
+	}
+	print STDERR "fatal: (error " .
+	    $mediawiki->{error}->{code} . ': ' .
+	    $mediawiki->{error}->{details} . ")\n";
+	exit 1;
+}
+
+## Functions for listing pages on the remote wiki
+sub get_mw_tracked_pages {
+	my $pages = shift;
+	get_mw_page_list(\@tracked_pages, $pages);
+	return;
+}
+
+sub get_mw_page_list {
+	my $page_list = shift;
+	my $pages = shift;
+	my @some_pages = @{$page_list};
+	while (@some_pages) {
+		my $last_page = SLICE_SIZE;
+		if ($#some_pages < $last_page) {
+			$last_page = $#some_pages;
+		}
+		my @slice = @some_pages[0..$last_page];
+		get_mw_first_pages(\@slice, $pages);
+		@some_pages = @some_pages[(SLICE_SIZE + 1)..$#some_pages];
+	}
+	return;
+}
+
+sub get_mw_tracked_categories {
+	my $pages = shift;
+	foreach my $category (@tracked_categories) {
+		if (index($category, ':') < 0) {
+			# Mediawiki requires the Category
+			# prefix, but let's not force the user
+			# to specify it.
+			$category = "Category:${category}";
+		}
+		my $mw_pages = $mediawiki->list( {
+			action => 'query',
+			list => 'categorymembers',
+			cmtitle => $category,
+			cmlimit => 'max' } )
+			|| die $mediawiki->{error}->{code} . ': '
+				. $mediawiki->{error}->{details} . "\n";
+		foreach my $page (@{$mw_pages}) {
+			$pages->{$page->{title}} = $page;
+		}
+	}
+	return;
+}
+
+sub get_mw_tracked_namespaces {
+    my $pages = shift;
+    foreach my $local_namespace (sort @tracked_namespaces) {
+        my $namespace_id;
+        if ($local_namespace eq "(Main)") {
+            $namespace_id = 0;
+        } else {
+            $namespace_id = get_mw_namespace_id($local_namespace);
+        }
+        # virtual namespaces don't support allpages
+        next if !defined($namespace_id) || $namespace_id < 0;
+        my $mw_pages = $mediawiki->list( {
+            action => 'query',
+            list => 'allpages',
+            apnamespace => $namespace_id,
+            aplimit => 'max' } )
+            || die $mediawiki->{error}->{code} . ': '
+                . $mediawiki->{error}->{details} . "\n";
+        print {*STDERR} "$#{$mw_pages} found in namespace $local_namespace ($namespace_id)\n";
+        foreach my $page (@{$mw_pages}) {
+            $pages->{$page->{title}} = $page;
+        }
+    }
+    return;
+}
+
+sub get_mw_all_pages {
+	my $pages = shift;
+	# No user-provided list, get the list of pages from the API.
+	my $mw_pages = $mediawiki->list({
+		action => 'query',
+		list => 'allpages',
+		aplimit => 'max'
+	});
+	if (!defined($mw_pages)) {
+		fatal_mw_error("get the list of wiki pages");
+	}
+	foreach my $page (@{$mw_pages}) {
+		$pages->{$page->{title}} = $page;
+	}
+	return;
+}
+
+# queries the wiki for a set of pages. Meant to be used within a loop
+# querying the wiki for slices of page list.
+sub get_mw_first_pages {
+	my $some_pages = shift;
+	my @some_pages = @{$some_pages};
+
+	my $pages = shift;
+
+	# pattern 'page1|page2|...' required by the API
+	my $titles = join('|', @some_pages);
+
+	my $mw_pages = $mediawiki->api({
+		action => 'query',
+		titles => $titles,
+	});
+	if (!defined($mw_pages)) {
+		fatal_mw_error("query the list of wiki pages");
+	}
+	while (my ($id, $page) = each(%{$mw_pages->{query}->{pages}})) {
+		if ($id < 0) {
+			print {*STDERR} "Warning: page $page->{title} not found on wiki\n";
+		} else {
+			$pages->{$page->{title}} = $page;
+		}
+	}
+	return;
+}
+
+# Get the list of pages to be fetched according to configuration.
+sub get_mw_pages {
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+
+	print {*STDERR} "Listing pages on remote wiki...\n";
+
+	my %pages; # hash on page titles to avoid duplicates
+	my $user_defined;
+	if (@tracked_pages) {
+		$user_defined = 1;
+		# The user provided a list of pages titles, but we
+		# still need to query the API to get the page IDs.
+		get_mw_tracked_pages(\%pages);
+	}
+	if (@tracked_categories) {
+		$user_defined = 1;
+		get_mw_tracked_categories(\%pages);
+	}
+	if (@tracked_namespaces) {
+		$user_defined = 1;
+		get_mw_tracked_namespaces(\%pages);
+	}
+	if (!$user_defined) {
+		get_mw_all_pages(\%pages);
+	}
+	if ($import_media) {
+		print {*STDERR} "Getting media files for selected pages...\n";
+		if ($user_defined) {
+			get_linked_mediafiles(\%pages);
+		} else {
+			get_all_mediafiles(\%pages);
+		}
+	}
+	print {*STDERR} (scalar keys %pages) . " pages found.\n";
+	return %pages;
+}
+
+# usage: $out = run_git("command args");
+#        $out = run_git("command args", "raw"); # don't interpret output as UTF-8.
+sub run_git {
+	my $args = shift;
+	my $encoding = (shift || 'encoding(UTF-8)');
+	open(my $git, "-|:${encoding}", "git ${args}")
+	    or die "Unable to fork: $!\n";
+	my $res = do {
+		local $/ = undef;
+		<$git>
+	};
+	close($git);
+
+	return $res;
+}
+
+
+sub get_all_mediafiles {
+	my $pages = shift;
+	# Attach list of all pages for media files from the API,
+	# they are in a different namespace, only one namespace
+	# can be queried at the same moment
+	my $mw_pages = $mediawiki->list({
+		action => 'query',
+		list => 'allpages',
+		apnamespace => get_mw_namespace_id('File'),
+		aplimit => 'max'
+	});
+	if (!defined($mw_pages)) {
+		print {*STDERR} "fatal: could not get the list of pages for media files.\n";
+		print {*STDERR} "fatal: '$url' does not appear to be a mediawiki\n";
+		print {*STDERR} "fatal: make sure '$url/api.php' is a valid page.\n";
+		exit 1;
+	}
+	foreach my $page (@{$mw_pages}) {
+		$pages->{$page->{title}} = $page;
+	}
+	return;
+}
+
+sub get_linked_mediafiles {
+	my $pages = shift;
+	my @titles = map { $_->{title} } values(%{$pages});
+
+	my $batch = BATCH_SIZE;
+	while (@titles) {
+		if ($#titles < $batch) {
+			$batch = $#titles;
+		}
+		my @slice = @titles[0..$batch];
+
+		# pattern 'page1|page2|...' required by the API
+		my $mw_titles = join('|', @slice);
+
+		# Media files could be included or linked from
+		# a page, get all related
+		my $query = {
+			action => 'query',
+			prop => 'links|images',
+			titles => $mw_titles,
+			plnamespace => get_mw_namespace_id('File'),
+			pllimit => 'max'
+		};
+		my $result = $mediawiki->api($query);
+
+		while (my ($id, $page) = each(%{$result->{query}->{pages}})) {
+			my @media_titles;
+			if (defined($page->{links})) {
+				my @link_titles
+				    = map { $_->{title} } @{$page->{links}};
+				push(@media_titles, @link_titles);
+			}
+			if (defined($page->{images})) {
+				my @image_titles
+				    = map { $_->{title} } @{$page->{images}};
+				push(@media_titles, @image_titles);
+			}
+			if (@media_titles) {
+				get_mw_page_list(\@media_titles, $pages);
+			}
+		}
+
+		@titles = @titles[($batch+1)..$#titles];
+	}
+	return;
+}
+
+sub get_mw_mediafile_for_page_revision {
+	# Name of the file on Wiki, with the prefix.
+	my $filename = shift;
+	my $timestamp = shift;
+	my %mediafile;
+
+	# Search if on a media file with given timestamp exists on
+	# MediaWiki. In that case download the file.
+	my $query = {
+		action => 'query',
+		prop => 'imageinfo',
+		titles => "File:${filename}",
+		iistart => $timestamp,
+		iiend => $timestamp,
+		iiprop => 'timestamp|archivename|url',
+		iilimit => 1
+	};
+	my $result = $mediawiki->api($query);
+
+	my ($fileid, $file) = each( %{$result->{query}->{pages}} );
+	# If not defined it means there is no revision of the file for
+	# given timestamp.
+	if (defined($file->{imageinfo})) {
+		$mediafile{title} = $filename;
+
+		my $fileinfo = pop(@{$file->{imageinfo}});
+		$mediafile{timestamp} = $fileinfo->{timestamp};
+		# Mediawiki::API's download function doesn't support https URLs
+		# and can't download old versions of files.
+		print {*STDERR} "\tDownloading file $mediafile{title}, version $mediafile{timestamp}\n";
+		$mediafile{content} = download_mw_mediafile($fileinfo->{url});
+	}
+	return %mediafile;
+}
+
+sub download_mw_mediafile {
+	my $download_url = shift;
+
+	my $response = $mediawiki->{ua}->get($download_url);
+	if ($response->code == HTTP_CODE_OK) {
+		# It is tempting to return
+		# $response->decoded_content({charset => "none"}), but
+		# when doing so, utf8::downgrade($content) fails with
+		# "Wide character in subroutine entry".
+		$response->decode();
+		return $response->content();
+	} else {
+		print {*STDERR} "Error downloading mediafile from :\n";
+		print {*STDERR} "URL: ${download_url}\n";
+		print {*STDERR} 'Server response: ' . $response->code . q{ } . $response->message . "\n";
+		exit 1;
+	}
+}
+
+sub get_last_local_revision {
+	# Get note regarding last mediawiki revision
+	my $note = run_git("notes --ref=${remotename}/mediawiki show refs/mediawiki/${remotename}/master 2>/dev/null");
+	my @note_info = split(/ /, $note);
+
+	my $lastrevision_number;
+	if (!(defined($note_info[0]) && $note_info[0] eq 'mediawiki_revision:')) {
+		print {*STDERR} 'No previous mediawiki revision found';
+		$lastrevision_number = 0;
+	} else {
+		# Notes are formatted : mediawiki_revision: #number
+		$lastrevision_number = $note_info[1];
+		chomp($lastrevision_number);
+		print {*STDERR} "Last local mediawiki revision found is ${lastrevision_number}";
+	}
+	return $lastrevision_number;
+}
+
+# Get the last remote revision without taking in account which pages are
+# tracked or not. This function makes a single request to the wiki thus
+# avoid a loop onto all tracked pages. This is useful for the fetch-by-rev
+# option.
+sub get_last_global_remote_rev {
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+
+	my $query = {
+		action => 'query',
+		list => 'recentchanges',
+		prop => 'revisions',
+		rclimit => '1',
+		rcdir => 'older',
+	};
+	my $result = $mediawiki->api($query);
+	return $result->{query}->{recentchanges}[0]->{revid};
+}
+
+# Get the last remote revision concerning the tracked pages and the tracked
+# categories.
+sub get_last_remote_revision {
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+
+	my %pages_hash = get_mw_pages();
+	my @pages = values(%pages_hash);
+
+	my $max_rev_num = 0;
+
+	print {*STDERR} "Getting last revision id on tracked pages...\n";
+
+	foreach my $page (@pages) {
+		my $id = $page->{pageid};
+
+		my $query = {
+			action => 'query',
+			prop => 'revisions',
+			rvprop => 'ids|timestamp',
+			pageids => $id,
+		};
+
+		my $result = $mediawiki->api($query);
+
+		my $lastrev = pop(@{$result->{query}->{pages}->{$id}->{revisions}});
+
+		$basetimestamps{$lastrev->{revid}} = $lastrev->{timestamp};
+
+		$max_rev_num = ($lastrev->{revid} > $max_rev_num ? $lastrev->{revid} : $max_rev_num);
+	}
+
+	print {*STDERR} "Last remote revision found is $max_rev_num.\n";
+	return $max_rev_num;
+}
+
+# Clean content before sending it to MediaWiki
+sub mediawiki_clean {
+	my $string = shift;
+	my $page_created = shift;
+	# Mediawiki does not allow blank space at the end of a page and ends with a single \n.
+	# This function right trims a string and adds a \n at the end to follow this rule
+	$string =~ s/\s+$//;
+	if ($string eq EMPTY && $page_created) {
+		# Creating empty pages is forbidden.
+		$string = EMPTY_CONTENT;
+	}
+	return $string."\n";
+}
+
+# Filter applied on MediaWiki data before adding them to Git
+sub mediawiki_smudge {
+	my $string = shift;
+	if ($string eq EMPTY_CONTENT) {
+		$string = EMPTY;
+	}
+	# This \n is important. This is due to mediawiki's way to handle end of files.
+	return "${string}\n";
+}
+
+sub literal_data {
+	my ($content) = @_;
+	print {*STDOUT} 'data ', bytes::length($content), "\n", $content;
+	return;
+}
+
+sub literal_data_raw {
+	# Output possibly binary content.
+	my ($content) = @_;
+	# Avoid confusion between size in bytes and in characters
+	utf8::downgrade($content);
+	binmode STDOUT, ':raw';
+	print {*STDOUT} 'data ', bytes::length($content), "\n", $content;
+	binmode STDOUT, ':encoding(UTF-8)';
+	return;
+}
+
+sub mw_capabilities {
+	# Revisions are imported to the private namespace
+	# refs/mediawiki/$remotename/ by the helper and fetched into
+	# refs/remotes/$remotename later by fetch.
+	print {*STDOUT} "refspec refs/heads/*:refs/mediawiki/${remotename}/*\n";
+	print {*STDOUT} "import\n";
+	print {*STDOUT} "list\n";
+	print {*STDOUT} "push\n";
+	if ($dumb_push) {
+		print {*STDOUT} "no-private-update\n";
+	}
+	print {*STDOUT} "\n";
+	return;
+}
+
+sub mw_list {
+	# MediaWiki do not have branches, we consider one branch arbitrarily
+	# called master, and HEAD pointing to it.
+	print {*STDOUT} "? refs/heads/master\n";
+	print {*STDOUT} "\@refs/heads/master HEAD\n";
+	print {*STDOUT} "\n";
+	return;
+}
+
+sub mw_option {
+	print {*STDERR} "remote-helper command 'option $_[0]' not yet implemented\n";
+	print {*STDOUT} "unsupported\n";
+	return;
+}
+
+sub fetch_mw_revisions_for_page {
+	my $page = shift;
+	my $id = shift;
+	my $fetch_from = shift;
+	my @page_revs = ();
+	my $query = {
+		action => 'query',
+		prop => 'revisions',
+		rvprop => 'ids',
+		rvdir => 'newer',
+		rvstartid => $fetch_from,
+		rvlimit => 500,
+		pageids => $id,
+
+		# Let MediaWiki know that we support the latest API.
+		continue => '',
+	};
+
+	my $revnum = 0;
+	# Get 500 revisions at a time due to the mediawiki api limit
+	while (1) {
+		my $result = $mediawiki->api($query);
+
+		# Parse each of those 500 revisions
+		foreach my $revision (@{$result->{query}->{pages}->{$id}->{revisions}}) {
+			my $page_rev_ids;
+			$page_rev_ids->{pageid} = $page->{pageid};
+			$page_rev_ids->{revid} = $revision->{revid};
+			push(@page_revs, $page_rev_ids);
+			$revnum++;
+		}
+
+		if ($result->{'query-continue'}) { # For legacy APIs
+			$query->{rvstartid} = $result->{'query-continue'}->{revisions}->{rvstartid};
+		} elsif ($result->{continue}) { # For newer APIs
+			$query->{rvstartid} = $result->{continue}->{rvcontinue};
+			$query->{continue} = $result->{continue}->{continue};
+		} else {
+			last;
+		}
+	}
+	if ($shallow_import && @page_revs) {
+		print {*STDERR} "  Found 1 revision (shallow import).\n";
+		@page_revs = sort {$b->{revid} <=> $a->{revid}} (@page_revs);
+		return $page_revs[0];
+	}
+	print {*STDERR} "  Found ${revnum} revision(s).\n";
+	return @page_revs;
+}
+
+sub fetch_mw_revisions {
+	my $pages = shift; my @pages = @{$pages};
+	my $fetch_from = shift;
+
+	my @revisions = ();
+	my $n = 1;
+	foreach my $page (@pages) {
+		my $id = $page->{pageid};
+		print {*STDERR} "page ${n}/", scalar(@pages), ': ', $page->{title}, "\n";
+		$n++;
+		my @page_revs = fetch_mw_revisions_for_page($page, $id, $fetch_from);
+		@revisions = (@page_revs, @revisions);
+	}
+
+	return ($n, @revisions);
+}
+
+sub fe_escape_path {
+    my $path = shift;
+    $path =~ s/\\/\\\\/g;
+    $path =~ s/"/\\"/g;
+    $path =~ s/\n/\\n/g;
+    return qq("${path}");
+}
+
+sub import_file_revision {
+	my $commit = shift;
+	my %commit = %{$commit};
+	my $full_import = shift;
+	my $n = shift;
+	my $mediafile = shift;
+	my %mediafile;
+	if ($mediafile) {
+		%mediafile = %{$mediafile};
+	}
+
+	my $title = $commit{title};
+	my $comment = $commit{comment};
+	my $content = $commit{content};
+	my $author = $commit{author};
+	my $date = $commit{date};
+
+	print {*STDOUT} "commit refs/mediawiki/${remotename}/master\n";
+	print {*STDOUT} "mark :${n}\n";
+	print {*STDOUT} "committer ${author} <${author}\@${wiki_name}> " . $date->epoch . " +0000\n";
+	literal_data($comment);
+
+	# If it's not a clone, we need to know where to start from
+	if (!$full_import && $n == 1) {
+		print {*STDOUT} "from refs/mediawiki/${remotename}/master^0\n";
+	}
+	if ($content ne DELETED_CONTENT) {
+		print {*STDOUT} 'M 644 inline ' .
+		    fe_escape_path("${title}.mw") . "\n";
+		literal_data($content);
+		if (%mediafile) {
+			print {*STDOUT} 'M 644 inline '
+			    . fe_escape_path($mediafile{title}) . "\n";
+			literal_data_raw($mediafile{content});
+		}
+		print {*STDOUT} "\n\n";
+	} else {
+		print {*STDOUT} 'D ' . fe_escape_path("${title}.mw") . "\n";
+	}
+
+	# mediawiki revision number in the git note
+	if ($full_import && $n == 1) {
+		print {*STDOUT} "reset refs/notes/${remotename}/mediawiki\n";
+	}
+	print {*STDOUT} "commit refs/notes/${remotename}/mediawiki\n";
+	print {*STDOUT} "committer ${author} <${author}\@${wiki_name}> " . $date->epoch . " +0000\n";
+	literal_data('Note added by git-mediawiki during import');
+	if (!$full_import && $n == 1) {
+		print {*STDOUT} "from refs/notes/${remotename}/mediawiki^0\n";
+	}
+	print {*STDOUT} "N inline :${n}\n";
+	literal_data("mediawiki_revision: $commit{mw_revision}");
+	print {*STDOUT} "\n\n";
+	return;
+}
+
+# parse a sequence of
+# <cmd> <arg1>
+# <cmd> <arg2>
+# \n
+# (like batch sequence of import and sequence of push statements)
+sub get_more_refs {
+	my $cmd = shift;
+	my @refs;
+	while (1) {
+		my $line = <STDIN>;
+		if ($line =~ /^$cmd (.*)$/) {
+			push(@refs, $1);
+		} elsif ($line eq "\n") {
+			return @refs;
+		} else {
+			die("Invalid command in a '$cmd' batch: $_\n");
+		}
+	}
+	return;
+}
+
+sub mw_import {
+	# multiple import commands can follow each other.
+	my @refs = (shift, get_more_refs('import'));
+	foreach my $ref (@refs) {
+		mw_import_ref($ref);
+	}
+	print {*STDOUT} "done\n";
+	return;
+}
+
+sub mw_import_ref {
+	my $ref = shift;
+	# The remote helper will call "import HEAD" and
+	# "import refs/heads/master".
+	# Since HEAD is a symbolic ref to master (by convention,
+	# followed by the output of the command "list" that we gave),
+	# we don't need to do anything in this case.
+	if ($ref eq 'HEAD') {
+		return;
+	}
+
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+
+	print {*STDERR} "Searching revisions...\n";
+	my $last_local = get_last_local_revision();
+	my $fetch_from = $last_local + 1;
+	if ($fetch_from == 1) {
+		print {*STDERR} ", fetching from beginning.\n";
+	} else {
+		print {*STDERR} ", fetching from here.\n";
+	}
+
+	my $n = 0;
+	if ($fetch_strategy eq 'by_rev') {
+		print {*STDERR} "Fetching & writing export data by revs...\n";
+		$n = mw_import_ref_by_revs($fetch_from);
+	} elsif ($fetch_strategy eq 'by_page') {
+		print {*STDERR} "Fetching & writing export data by pages...\n";
+		$n = mw_import_ref_by_pages($fetch_from);
+	} else {
+		print {*STDERR} qq(fatal: invalid fetch strategy "${fetch_strategy}".\n);
+		print {*STDERR} "Check your configuration variables remote.${remotename}.fetchStrategy and mediawiki.fetchStrategy\n";
+		exit 1;
+	}
+
+	if ($fetch_from == 1 && $n == 0) {
+		print {*STDERR} "You appear to have cloned an empty MediaWiki.\n";
+		# Something has to be done remote-helper side. If nothing is done, an error is
+		# thrown saying that HEAD is referring to unknown object 0000000000000000000
+		# and the clone fails.
+	}
+	return;
+}
+
+sub mw_import_ref_by_pages {
+
+	my $fetch_from = shift;
+	my %pages_hash = get_mw_pages();
+	my @pages = values(%pages_hash);
+
+	my ($n, @revisions) = fetch_mw_revisions(\@pages, $fetch_from);
+
+	@revisions = sort {$a->{revid} <=> $b->{revid}} @revisions;
+	my @revision_ids = map { $_->{revid} } @revisions;
+
+	return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
+}
+
+sub mw_import_ref_by_revs {
+
+	my $fetch_from = shift;
+	my %pages_hash = get_mw_pages();
+
+	my $last_remote = get_last_global_remote_rev();
+	my @revision_ids = $fetch_from..$last_remote;
+	return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
+}
+
+# Import revisions given in second argument (array of integers).
+# Only pages appearing in the third argument (hash indexed by page titles)
+# will be imported.
+sub mw_import_revids {
+	my $fetch_from = shift;
+	my $revision_ids = shift;
+	my $pages = shift;
+
+	my $n = 0;
+	my $n_actual = 0;
+	my $last_timestamp = 0; # Placeholder in case $rev->timestamp is undefined
+
+	foreach my $pagerevid (@{$revision_ids}) {
+	        # Count page even if we skip it, since we display
+		# $n/$total and $total includes skipped pages.
+		$n++;
+
+		# fetch the content of the pages
+		my $query = {
+			action => 'query',
+			prop => 'revisions',
+			rvprop => 'content|timestamp|comment|user|ids',
+			revids => $pagerevid,
+		};
+
+		my $result = $mediawiki->api($query);
+
+		if (!$result) {
+			die "Failed to retrieve modified page for revision $pagerevid\n";
+		}
+
+		if (defined($result->{query}->{badrevids}->{$pagerevid})) {
+			# The revision id does not exist on the remote wiki.
+			next;
+		}
+
+		if (!defined($result->{query}->{pages})) {
+			die "Invalid revision ${pagerevid}.\n";
+		}
+
+		my @result_pages = values(%{$result->{query}->{pages}});
+		my $result_page = $result_pages[0];
+		my $rev = $result_pages[0]->{revisions}->[0];
+
+		my $page_title = $result_page->{title};
+
+		if (!exists($pages->{$page_title})) {
+			print {*STDERR} "${n}/", scalar(@{$revision_ids}),
+				": Skipping revision #$rev->{revid} of ${page_title}\n";
+			next;
+		}
+
+		$n_actual++;
+
+		my %commit;
+		$commit{author} = $rev->{user} || 'Anonymous';
+		$commit{comment} = $rev->{comment} || EMPTY_MESSAGE;
+		$commit{title} = smudge_filename($page_title);
+		$commit{mw_revision} = $rev->{revid};
+		$commit{content} = mediawiki_smudge($rev->{'*'});
+
+		if (!defined($rev->{timestamp})) {
+			$last_timestamp++;
+		} else {
+			$last_timestamp = $rev->{timestamp};
+		}
+		$commit{date} = DateTime::Format::ISO8601->parse_datetime($last_timestamp);
+
+		# Differentiates classic pages and media files.
+		my ($namespace, $filename) = $page_title =~ /^([^:]*):(.*)$/;
+		my %mediafile;
+		if ($namespace) {
+			my $id = get_mw_namespace_id($namespace);
+			if ($id && $id == get_mw_namespace_id('File')) {
+				%mediafile = get_mw_mediafile_for_page_revision($filename, $rev->{timestamp});
+			}
+		}
+		# If this is a revision of the media page for new version
+		# of a file do one common commit for both file and media page.
+		# Else do commit only for that page.
+		print {*STDERR} "${n}/", scalar(@{$revision_ids}), ": Revision #$rev->{revid} of $commit{title}\n";
+		import_file_revision(\%commit, ($fetch_from == 1), $n_actual, \%mediafile);
+	}
+
+	return $n_actual;
+}
+
+sub error_non_fast_forward {
+	my $advice = run_git('config --bool advice.pushNonFastForward');
+	chomp($advice);
+	if ($advice ne 'false') {
+		# Native git-push would show this after the summary.
+		# We can't ask it to display it cleanly, so print it
+		# ourselves before.
+		print {*STDERR} "To prevent you from losing history, non-fast-forward updates were rejected\n";
+		print {*STDERR} "Merge the remote changes (e.g. 'git pull') before pushing again. See the\n";
+		print {*STDERR} "'Note about fast-forwards' section of 'git push --help' for details.\n";
+	}
+	print {*STDOUT} qq(error $_[0] "non-fast-forward"\n);
+	return 0;
+}
+
+sub mw_upload_file {
+	my $complete_file_name = shift;
+	my $new_sha1 = shift;
+	my $extension = shift;
+	my $file_deleted = shift;
+	my $summary = shift;
+	my $newrevid;
+	my $path = "File:${complete_file_name}";
+	my %hashFiles = get_allowed_file_extensions();
+	if (!exists($hashFiles{$extension})) {
+		print {*STDERR} "${complete_file_name} is not a permitted file on this wiki.\n";
+		print {*STDERR} "Check the configuration of file uploads in your mediawiki.\n";
+		return $newrevid;
+	}
+	# Deleting and uploading a file requires a privileged user
+	if ($file_deleted) {
+		$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+		my $query = {
+			action => 'delete',
+			title => $path,
+			reason => $summary
+		};
+		if (!$mediawiki->edit($query)) {
+			print {*STDERR} "Failed to delete file on remote wiki\n";
+			print {*STDERR} "Check your permissions on the remote site. Error code:\n";
+			print {*STDERR} $mediawiki->{error}->{code} . ':' . $mediawiki->{error}->{details};
+			exit 1;
+		}
+	} else {
+		# Don't let perl try to interpret file content as UTF-8 => use "raw"
+		my $content = run_git("cat-file blob ${new_sha1}", 'raw');
+		if ($content ne EMPTY) {
+			$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+			$mediawiki->{config}->{upload_url} =
+				"${url}/index.php/Special:Upload";
+			$mediawiki->edit({
+				action => 'upload',
+				filename => $complete_file_name,
+				comment => $summary,
+				file => [undef,
+					 $complete_file_name,
+					 Content => $content],
+				ignorewarnings => 1,
+			}, {
+				skip_encoding => 1
+			} ) || die $mediawiki->{error}->{code} . ':'
+				 . $mediawiki->{error}->{details} . "\n";
+			my $last_file_page = $mediawiki->get_page({title => $path});
+			$newrevid = $last_file_page->{revid};
+			print {*STDERR} "Pushed file: ${new_sha1} - ${complete_file_name}.\n";
+		} else {
+			print {*STDERR} "Empty file ${complete_file_name} not pushed.\n";
+		}
+	}
+	return $newrevid;
+}
+
+sub mw_push_file {
+	my $diff_info = shift;
+	# $diff_info contains a string in this format:
+	# 100644 100644 <sha1_of_blob_before_commit> <sha1_of_blob_now> <status>
+	my @diff_info_split = split(/[ \t]/, $diff_info);
+
+	# Filename, including .mw extension
+	my $complete_file_name = shift;
+	# Commit message
+	my $summary = shift;
+	# MediaWiki revision number. Keep the previous one by default,
+	# in case there's no edit to perform.
+	my $oldrevid = shift;
+	my $newrevid;
+
+	if ($summary eq EMPTY_MESSAGE) {
+		$summary = EMPTY;
+	}
+
+	my $new_sha1 = $diff_info_split[3];
+	my $old_sha1 = $diff_info_split[2];
+	my $page_created = ($old_sha1 eq NULL_SHA1);
+	my $page_deleted = ($new_sha1 eq NULL_SHA1);
+	$complete_file_name = clean_filename($complete_file_name);
+
+	my ($title, $extension) = $complete_file_name =~ /^(.*)\.([^\.]*)$/;
+	if (!defined($extension)) {
+		$extension = EMPTY;
+	}
+	if ($extension eq 'mw') {
+		my $ns = get_mw_namespace_id_for_page($complete_file_name);
+		if ($ns && $ns == get_mw_namespace_id('File') && (!$export_media)) {
+			print {*STDERR} "Ignoring media file related page: ${complete_file_name}\n";
+			return ($oldrevid, 'ok');
+		}
+		my $file_content;
+		if ($page_deleted) {
+			# Deleting a page usually requires
+			# special privileges. A common
+			# convention is to replace the page
+			# with this content instead:
+			$file_content = DELETED_CONTENT;
+		} else {
+			$file_content = run_git("cat-file blob ${new_sha1}");
+		}
+
+		$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+
+		my $result = $mediawiki->edit( {
+			action => 'edit',
+			summary => $summary,
+			title => $title,
+			basetimestamp => $basetimestamps{$oldrevid},
+			text => mediawiki_clean($file_content, $page_created),
+				  }, {
+					  skip_encoding => 1 # Helps with names with accentuated characters
+				  });
+		if (!$result) {
+			if ($mediawiki->{error}->{code} == 3) {
+				# edit conflicts, considered as non-fast-forward
+				print {*STDERR} 'Warning: Error ' .
+				    $mediawiki->{error}->{code} .
+				    ' from mediawiki: ' . $mediawiki->{error}->{details} .
+				    ".\n";
+				return ($oldrevid, 'non-fast-forward');
+			} else {
+				# Other errors. Shouldn't happen => just die()
+				die 'Fatal: Error ' .
+				    $mediawiki->{error}->{code} .
+				    ' from mediawiki: ' . $mediawiki->{error}->{details} . "\n";
+			}
+		}
+		$newrevid = $result->{edit}->{newrevid};
+		print {*STDERR} "Pushed file: ${new_sha1} - ${title}\n";
+	} elsif ($export_media) {
+		$newrevid = mw_upload_file($complete_file_name, $new_sha1,
+					   $extension, $page_deleted,
+					   $summary);
+	} else {
+		print {*STDERR} "Ignoring media file ${title}\n";
+	}
+	$newrevid = ($newrevid or $oldrevid);
+	return ($newrevid, 'ok');
+}
+
+sub mw_push {
+	# multiple push statements can follow each other
+	my @refsspecs = (shift, get_more_refs('push'));
+	my $pushed;
+	for my $refspec (@refsspecs) {
+		my ($force, $local, $remote) = $refspec =~ /^(\+)?([^:]*):([^:]*)$/
+		    or die("Invalid refspec for push. Expected <src>:<dst> or +<src>:<dst>\n");
+		if ($force) {
+			print {*STDERR} "Warning: forced push not allowed on a MediaWiki.\n";
+		}
+		if ($local eq EMPTY) {
+			print {*STDERR} "Cannot delete remote branch on a MediaWiki\n";
+			print {*STDOUT} "error ${remote} cannot delete\n";
+			next;
+		}
+		if ($remote ne 'refs/heads/master') {
+			print {*STDERR} "Only push to the branch 'master' is supported on a MediaWiki\n";
+			print {*STDOUT} "error ${remote} only master allowed\n";
+			next;
+		}
+		if (mw_push_revision($local, $remote)) {
+			$pushed = 1;
+		}
+	}
+
+	# Notify Git that the push is done
+	print {*STDOUT} "\n";
+
+	if ($pushed && $dumb_push) {
+		print {*STDERR} "Just pushed some revisions to MediaWiki.\n";
+		print {*STDERR} "The pushed revisions now have to be re-imported, and your current branch\n";
+		print {*STDERR} "needs to be updated with these re-imported commits. You can do this with\n";
+		print {*STDERR} "\n";
+		print {*STDERR} "  git pull --rebase\n";
+		print {*STDERR} "\n";
+	}
+	return;
+}
+
+sub mw_push_revision {
+	my $local = shift;
+	my $remote = shift; # actually, this has to be "refs/heads/master" at this point.
+	my $last_local_revid = get_last_local_revision();
+	print {*STDERR} ".\n"; # Finish sentence started by get_last_local_revision()
+	my $last_remote_revid = get_last_remote_revision();
+	my $mw_revision = $last_remote_revid;
+
+	# Get sha1 of commit pointed by local HEAD
+	my $HEAD_sha1 = run_git("rev-parse ${local} 2>/dev/null");
+	chomp($HEAD_sha1);
+	# Get sha1 of commit pointed by remotes/$remotename/master
+	my $remoteorigin_sha1 = run_git("rev-parse refs/remotes/${remotename}/master 2>/dev/null");
+	chomp($remoteorigin_sha1);
+
+	if ($last_local_revid > 0 &&
+	    $last_local_revid < $last_remote_revid) {
+		return error_non_fast_forward($remote);
+	}
+
+	if ($HEAD_sha1 eq $remoteorigin_sha1) {
+		# nothing to push
+		return 0;
+	}
+
+	# Get every commit in between HEAD and refs/remotes/origin/master,
+	# including HEAD and refs/remotes/origin/master
+	my @commit_pairs = ();
+	if ($last_local_revid > 0) {
+		my $parsed_sha1 = $remoteorigin_sha1;
+		# Find a path from last MediaWiki commit to pushed commit
+		print {*STDERR} "Computing path from local to remote ...\n";
+		my @local_ancestry = split(/\n/, run_git("rev-list --boundary --parents ${local} ^${parsed_sha1}"));
+		my %local_ancestry;
+		foreach my $line (@local_ancestry) {
+			if (my ($child, $parents) = $line =~ /^-?([a-f0-9]+) ([a-f0-9 ]+)/) {
+				foreach my $parent (split(/ /, $parents)) {
+					$local_ancestry{$parent} = $child;
+				}
+			} elsif (!$line =~ /^([a-f0-9]+)/) {
+				die "Unexpected output from git rev-list: ${line}\n";
+			}
+		}
+		while ($parsed_sha1 ne $HEAD_sha1) {
+			my $child = $local_ancestry{$parsed_sha1};
+			if (!$child) {
+				print {*STDERR} "Cannot find a path in history from remote commit to last commit\n";
+				return error_non_fast_forward($remote);
+			}
+			push(@commit_pairs, [$parsed_sha1, $child]);
+			$parsed_sha1 = $child;
+		}
+	} else {
+		# No remote mediawiki revision. Export the whole
+		# history (linearized with --first-parent)
+		print {*STDERR} "Warning: no common ancestor, pushing complete history\n";
+		my $history = run_git("rev-list --first-parent --children ${local}");
+		my @history = split(/\n/, $history);
+		@history = @history[1..$#history];
+		foreach my $line (reverse @history) {
+			my @commit_info_split = split(/[ \n]/, $line);
+			push(@commit_pairs, \@commit_info_split);
+		}
+	}
+
+	foreach my $commit_info_split (@commit_pairs) {
+		my $sha1_child = @{$commit_info_split}[0];
+		my $sha1_commit = @{$commit_info_split}[1];
+		my $diff_infos = run_git("diff-tree -r --raw -z ${sha1_child} ${sha1_commit}");
+		# TODO: we could detect rename, and encode them with a #redirect on the wiki.
+		# TODO: for now, it's just a delete+add
+		my @diff_info_list = split(/\0/, $diff_infos);
+		# Keep the subject line of the commit message as mediawiki comment for the revision
+		my $commit_msg = run_git(qq(log --no-walk --format="%s" ${sha1_commit}));
+		chomp($commit_msg);
+		# Push every blob
+		while (@diff_info_list) {
+			my $status;
+			# git diff-tree -z gives an output like
+			# <metadata>\0<filename1>\0
+			# <metadata>\0<filename2>\0
+			# and we've split on \0.
+			my $info = shift(@diff_info_list);
+			my $file = shift(@diff_info_list);
+			($mw_revision, $status) = mw_push_file($info, $file, $commit_msg, $mw_revision);
+			if ($status eq 'non-fast-forward') {
+				# we may already have sent part of the
+				# commit to MediaWiki, but it's too
+				# late to cancel it. Stop the push in
+				# the middle, but still give an
+				# accurate error message.
+				return error_non_fast_forward($remote);
+			}
+			if ($status ne 'ok') {
+				die("Unknown error from mw_push_file()\n");
+			}
+		}
+		if (!$dumb_push) {
+			run_git(qq(notes --ref=${remotename}/mediawiki add -f -m "mediawiki_revision: ${mw_revision}" ${sha1_commit}));
+		}
+	}
+
+	print {*STDOUT} "ok ${remote}\n";
+	return 1;
+}
+
+sub get_allowed_file_extensions {
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+
+	my $query = {
+		action => 'query',
+		meta => 'siteinfo',
+		siprop => 'fileextensions'
+		};
+	my $result = $mediawiki->api($query);
+	my @file_extensions = map { $_->{ext}} @{$result->{query}->{fileextensions}};
+	my %hashFile = map { $_ => 1 } @file_extensions;
+
+	return %hashFile;
+}
+
+# In memory cache for MediaWiki namespace ids.
+my %namespace_id;
+
+# Namespaces whose id is cached in the configuration file
+# (to avoid duplicates)
+my %cached_mw_namespace_id;
+
+# Return MediaWiki id for a canonical namespace name.
+# Ex.: "File", "Project".
+sub get_mw_namespace_id {
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
+	my $name = shift;
+
+	if (!exists $namespace_id{$name}) {
+		# Look at configuration file, if the record for that namespace is
+		# already cached. Namespaces are stored in form:
+		# "Name_of_namespace:Id_namespace", ex.: "File:6".
+		my @temp = split(/\n/,
+				 run_git("config --get-all remote.${remotename}.namespaceCache"));
+		chomp(@temp);
+		foreach my $ns (@temp) {
+			my ($n, $id) = split(/:/, $ns);
+			if ($id eq 'notANameSpace') {
+				$namespace_id{$n} = {is_namespace => 0};
+			} else {
+				$namespace_id{$n} = {is_namespace => 1, id => $id};
+			}
+			$cached_mw_namespace_id{$n} = 1;
+		}
+	}
+
+	if (!exists $namespace_id{$name}) {
+		print {*STDERR} "Namespace ${name} not found in cache, querying the wiki ...\n";
+		# NS not found => get namespace id from MW and store it in
+	        # configuration file.
+	        my $query = {
+	                action => 'query',
+	                meta => 'siteinfo',
+	                siprop => 'namespaces'
+	        };
+	        my $result = $mediawiki->api($query);
+
+	        while (my ($id, $ns) = each(%{$result->{query}->{namespaces}})) {
+	                if (defined($ns->{id}) && defined($ns->{canonical})) {
+				$namespace_id{$ns->{canonical}} = {is_namespace => 1, id => $ns->{id}};
+				if ($ns->{'*'}) {
+					# alias (e.g. french Fichier: as alias for canonical File:)
+					$namespace_id{$ns->{'*'}} = {is_namespace => 1, id => $ns->{id}};
+				}
+			}
+	        }
+	}
+
+	my $ns = $namespace_id{$name};
+	my $id;
+
+	if (!defined $ns) {
+		my @namespaces = map { s/ /_/g; $_; } sort keys %namespace_id;
+		print {*STDERR} "No such namespace ${name} on MediaWiki, known namespaces: @namespaces\n";
+		$ns = {is_namespace => 0};
+		$namespace_id{$name} = $ns;
+	}
+
+	if ($ns->{is_namespace}) {
+		$id = $ns->{id};
+	}
+
+	# Store "notANameSpace" as special value for inexisting namespaces
+	my $store_id = ($id || 'notANameSpace');
+
+	# Store explicitly requested namespaces on disk
+	if (!exists $cached_mw_namespace_id{$name}) {
+		run_git(qq(config --add remote.${remotename}.namespaceCache "${name}:${store_id}"));
+		$cached_mw_namespace_id{$name} = 1;
+	}
+	return $id;
+}
+
+sub get_mw_namespace_id_for_page {
+	my $namespace = shift;
+	if ($namespace =~ /^([^:]*):/) {
+		return get_mw_namespace_id($namespace);
+	} else {
+		return;
+	}
+}