Module:data consistency check

This module checks the validity and internal consistency of the language, language family, and script data used on Wiktionary: the modules in Category:Language data modules as well as Module:scripts/data.

Checks performed

For multiple data modules:

• Codes for languages, families and etymology-only languages must be unique and cannot clash with one another.
• Canonical names for languages, families, and etymology-only languages must not be found in the list of other names.
• Each name in the list of other names must appear only once.
• otherNames, if present, must be an array.
• Wikidata item IDs must be a positive integer or a string starting with Q and ending with decimal digits.

The following must be true of the data used by Module:languages:

• Each code must be defined in the correct submodule according to whether it is two-letter, three-letter or exceptional.
• The canonical name (field 1) must be present and must not be the same as the canonical name of another language.
• If field 2 is not nil, it must a valid Wikidata item ID.
• If field 3 or family is given and not nil, it must be a valid family code.
• If field 4 or scripts is given and not nil, it must be an array, and each string in the array must be a valid script code.
• If ancestors is given, it must be an array, and each string in the array must be a valid language or etymology language code.
• If family is given, it must be a valid family code.
• If type is given, it must be one of the recognised values (regular, reconstructed, appendix-constructed).
• If entry_name is given, it must be a table that contains either two arrays (from and to) or a string (remove_diacritics) or both.
• If sort_key is given, it may either be a string, or at table that in turn contains either two arrays (from and to) or a string (remove_diacritics).
• If entry_name or sort_key is given, the from array must be longer or equal in length to the to array.
• If standardChars is given, it must form a valid Lua string pattern when placed between square brackets with ^ before it ("[^...]). (It should match all characters regularly used in the language, but that cannot be tested.)
• If override_translit is set, translit must also be set, because there must be a transliteration module that can override manual transliteration.
• If link_tr is present, it must be true.
• Have no data keys besides these: 1, 2, 3, "entry_name", "sort_key", "display", "otherNames", "aliases", "varieties", "type", "scripts", "ancestors", "wikimedia_codes", "wikipedia_article", "standardChars", "translit", "override_translit", "link_tr".

Checks not performed:

• If translit is present, it should be the name of a module, and this module should contain a tr function that takes a pagename (and optionally a language code and script code) as arguments.
• If sort_key is a string, it should be the name of a module, and this module should contain a makeSortKey function that takes a pagename (and optionally a language code and script code) as arguments.
• If entry_name or sort_key is a table and contains a field remove_diacritics, the value of the field should be a string that forms a valid Lua pattern when it is placed inside negated set notation ([^...]).

These are not checked here, because module errors will quickly crop up in entries if these conditions are not met, assuming that Module:utilities attempts to generate a sortkey for a category pertaining to the language in question, or full_link attempts to use the transliteration module.

Module:languages/code to canonical name and Module:languages/canonical names must contain all the codes and canonical names found in the data submodules of Module:languages, and no more.

The following must be true of the data used by Module:etymology languages:

• canonicalName must be given.
• parent must be given must be a valid language, family or etymology-only language code.
• If ancestors is given, it must be an array, and each string in the array must be a valid language or etymology language code. The etymology language should also be listed as the ancestor of a regular language.
• Have no data keys besides these: "canonicalName", "otherNames", "parent", "ancestors", "wikipedia_article", "wikidata_item".

Codes in Module:families data must:

• Have canonicalName, which must not be the same as the canonical name of another family.
• If family is given, it must be a valid family code.
• Have at least one language or subfamily belonging to it.
• Have no data keys besides these: "canonicalName", "otherNames", "family", "protoLanguage", "wikidata_item".

Codes in Module:scripts data must:

• Have canonicalName.
• Have at least one language that lists it as one of its scripts.
• Have a characters pattern for script autodetection, and this must form a valid Lua string pattern when placed between square brackets ("[...]"). (It should match all characters in the script, but that cannot be tested.)
• Have no data keys besides these: "canonicalName", "otherNames", "parent", "systems", "wikipedia_article", "characters", "direction".

---

local export = {}

local m_language_data = require("Module:languages/data/all")
local m_language_codes = require("Module:languages/code to canonical name")
local m_language_canonical_names = require("Module:languages/canonical names")
local m_etym_language_data = require("Module:etymology languages/data")
local m_etym_language_codes = require("Module:etymology languages/code to canonical name")
local m_etym_language_canonical_names = require("Module:etymology languages/canonical names")
local m_family_data = require("Module:families/data")
local m_family_codes = require("Module:families/code to canonical name")
local m_family_canonical_names = require("Module:families/canonical names")
local m_script_data = require("Module:scripts/data")

local m_languages = require("Module:languages")
local m_links = require("Module:links")
local m_scripts = require("Module:scripts")
local m_script_utils = require("Module:script utilities")
local m_table = require("Module:table")
local Array = require("Module:array")

local messages

local function discrepancy(modname, ...)
	local ok, result = pcall(function(...) messages[modname]:insert(string.format(...)) end, ...)
	if not ok then
		mw.log(result, ...)
	end
	
end

local all_codes = {}

local language_names = {}
local family_names = {}
local script_names = {}

local nonempty_families = {}
local allowed_empty_families = {tbq = true}
local nonempty_scripts = {}
	
local function link(name)
	if not name then
		return "???"
	elseif name:find("[Ll]anguage$") then
		return "[[:Category:" .. name .. "|" .. name .. "]]"
	else
		return "[[:Category:" .. name .. " language|" .. name .. " language]]"
	end
end
	
local function link_script(name)
	if not name then
		return "???"
	elseif name:find("[Cc]ode$") or name:find("[Ss]emaphore$") then
		return "[[:Category:" .. name:gsub("^%l", string.upper) .. "|" .. name .. "]]"
	else
		return "[[:Category:" .. name .. " script|" .. name .. " script]]"
	end
end

local function invalid_keys_message(modname, code, data, invalid_keys, is_script)
	local plural = #invalid_keys ~= 1
	discrepancy(modname, "The data key%s %s for %s (<code>%s</code>) %s invalid.",
		plural and "s" or "",
		invalid_keys
			:map(
				function(key)
					return '<code>' .. key .. '</code>'
				end)
			:concat(", "),
		(is_script and link_script or link)(data[1]),
		code,
		plural and "are" or "is")
end

local function check_data_keys(valid_keys, is_script)
	valid_keys = Array(valid_keys):to_set()
	
	return function (modname, code, data)
		local invalid_keys
		for k in pairs(data) do
			if not valid_keys[k] then
				invalid_keys = invalid_keys or Array()
				invalid_keys:insert(k)
			end
		end
		if invalid_keys then
			invalid_keys_message(modname, code, data, invalid_keys, is_script)
		end
	end
end

-- Modification of isArray in [[Module:table]].
local function find_gap(t)
	local i = 0
	for _ in pairs(t) do
		i = i + 1
		if t[i] == nil then
			return i
		end
	end
end

local function check_true_or_nil(modname, code, data, field_name)
	if not (data[field_name] == nil or data[field_name] == true) then
		discrepancy(modname,
			"%s (<code>%s</code>) has an <code>%s</code> value that is not <code>nil</code> or <code>true</code>: %s",
			link(canonical_name), code, field_name,
			tostring(data.link_tr)
		)
	end
end

local function check_array(modname, code, data, array_name, subarray_name)
	local subtable = data
	if subarray_name then
		subtable = assert(data[subarray_name], subarray_name)
	end
	local array_type = type(subtable[array_name])
	if array_type == "table" then
		local gap = find_gap(subtable[array_name])
		if gap then
			discrepancy(modname, "The %s array in %sthe data table for %s (<code>%s</code>) has a gap at index %d.",
				array_name,
				subarray_name and "the " .. subarray_name .. " field in " or "",
				data[1],
				code, gap)
		else
			return true
		end
	else
		discrepancy(modname, "The %s field in %sthe data table for %s (<code>%s</code>) should be an array (table) but is %s.",
			array_name,
			subarray_name and "the " .. subarray_name .. " field in " or "",
			data[1],
			code,
			array_type == "nil" and "nil" or "a " .. array_type)
	end
end

local function check_wikidata_item(modname, code, data, key)
	local data_item = data[key]
	if data_item == nil then
		return
	elseif type(data_item) == "number" then
		if not require "Module:table".isPositiveInteger(data_item) then
			discrepancy(modname, "%g, the Wikidata item id for %s (<code>%s</code>), is not a positive integer or a string in the correct format.",
				data_item, data[1], code)
		end
	elseif type(data_item) == "string" then
		if not data_item:find "^Q%d+$" then
			discrepancy(modname, "%s, the Wikidata item id for %s (<code>%s</code>), is not a string in the correct format or a positive integer.",
				data_item, data[1], code)
		end
	end
end

local function check_other_names_or_aliases(modname, code, canonical_name, data, data_key, allow_nested)
	local array = data[data_key]
	if not array then
		return
	end
	check_array(modname, code, data, data_key)

	local names = {}
	local function check_other_name(other_name)
		if other_name == canonical_name then
			discrepancy(modname,
				"%s, the canonical name for <code>%s</code>, is repeated in the table of <code>%s</code>.",
				canonical_name, code, data_key)
		end
		if names[other_name] then
			discrepancy(modname,
				"The name %s is found twice or more in the list of <code>%s</code> for %s (<code>%s</code>).",
				other_name, data_key, canonical_name, code)
		end
		names[other_name] = true
	end

	for _, other_name in ipairs(array) do
		if type(other_name) == "table" then
			if not allow_nested then
				discrepancy(modname,
					"A nested table is found in the list of <code>%s</code> for %s (<code>%s</code>), but isn't allowed.",
					data_key, canonical_name, code)
			else
				for _, on in ipairs(other_name) do
					check_other_name(on)
				end
			end
		else
			check_other_name(other_name)
		end
	end
end

local function check_other_names_aliases_varieties(modname, code, canonical_name, data)
	if data.otherNames then
		check_other_names_or_aliases(modname, code, canonical_name, data, "otherNames")
	end
	if data.aliases then
		check_other_names_or_aliases(modname, code, canonical_name, data, "aliases")
	end
	if data.varieties then
		check_other_names_or_aliases(modname, code, canonical_name, data, "varieties", true)
	end
end

local get_codepoint = mw.ustring.codepoint
local function validate_pattern(pattern, modname, code, data, standardChars)
	if type(pattern) ~= "string" then
		discrepancy(modname, '"%s", the %spattern for %s (<code>%s</code>), is not a string.',
			pattern, standardChars and 'standard character ' or '', code, data[1])
	end
	local ranges
	for lower, higher in mw.ustring.gmatch(pattern, "(.)%-%%?(.)") do
		if get_codepoint(lower) >= get_codepoint(higher) then
			ranges = ranges or Array()
			table.insert(ranges, { lower, higher })
		end
	end
	if ranges and ranges[1] then
		local plural = #ranges ~= 1 and "s" or ""
		discrepancy(modname, '%s (<code>%s</code>) specifies an invalid pattern ' ..
			'for %scharacter detection: <code>"%s"</code>. The first codepoint%s ' ..
			'in the range%s %s %s must be less than the second.',
			link(data[1]), code, standardChars and 'standard ' or '', pattern, plural, plural,
			ranges
				:map(
					function(range)
						return range[1] .. "-" .. range[2] .. (" (U+%X, U+%X)")
							:format(get_codepoint(range[1]), get_codepoint(range[2]))
					end)
				:concat(", "),
			#ranges ~= 1 and "are" or "is")
	end
	if not pcall(mw.ustring.find, "", "[" .. pattern .. "]") then
		discrepancy(modname, '%s (<code>%s</code>) specifies an invalid pattern for ' ..
			(standardChars and 'standard' or '') .. ' character detection: <code>"%s"</code>',
			link(data.canonical_name), code, pattern)
	end
end

local remove_exceptions_addition = 0xF0000
local maximum_code_point = 0x10FFFF
local remove_exceptions_maximum_code_point = maximum_code_point - remove_exceptions_addition

local function check_entry_name_or_sortkey(modname, code, data, replacements_name)
	local canonical_name = data[1]
	
	local replacements = data[replacements_name]
	if type(replacements) == "string" then
		if not (replacements_name == "sort_key" or replacements_name == "entry_name") then
			discrepancy(modname, "The %s field in the data table for %s (<code>%s</code>) must be a table.",
				replacements_name, canonical_name, code)
		end
		return
	end
	
	if (replacements.from ~= nil) ~= (replacements.to ~= nil) then
		discrepancy(modname,
			"The <code>from</code> and <code>to</code> arrays in the <code>%s</code> table for %s (<code>%s</code>) are not both defined or both undefined.",
			replacements_name, canonical_name, code)
	elseif replacements.from then
		for _, key in ipairs { "from", "to" } do
			check_array(modname, code, data, key, replacements_name)
		end
	end
	
	if replacements.remove_diacritics and type(replacements.remove_diacritics) ~= "string" then
		discrepancy(modname,
			"The <code>remove_diacritics</code> field in the <code>%s</code> table for %s (<code>%s</code>) table must be a string.",
			replacements_name, canonical_name, code)
	end
	
	if replacements.remove_exceptions then
		if check_array(modname, code, data, "remove_exceptions", replacements_name) then
			for sequence_i, sequence in ipairs(replacements.remove_exceptions) do
				local code_point_i = 0
				for code_point in mw.ustring.gcodepoint(sequence) do
					code_point_i = code_point_i + 1
					if code_point > remove_exceptions_maximum_code_point then
						discrepancy(modname,
							"Code point #%d (0x%04X) in field #%d of the <code>remove_exceptions</code> array for %s (<code>%s</code>) is over U+%04X.",
							code_point_i, code_point, sequence_i, canonical_name, code, remove_exceptions_maximum_code_point)
					end
					
				end
			end
		end
	end
	
	if replacements.from and replacements.to
			and m_table.length(replacements.to) > m_table.length(replacements.from) then
		discrepancy(modname,
			"The <code>from</code> array in the <code>%s</code> table for %s (<code>%s</code>) must be shorter or the same length as the <code>to</code> array.",
			replacements_name, canonical_name, code)
	end
end

local function has_regular_language_child(parent_code)
	for code, data in pairs(m_language_data) do
		local ancestors = data.ancestors
		if ancestors then
			for _, ancestor in pairs(ancestors) do
				if ancestor == parent_code then
					return true
				end
			end
		end
	end
	return false
end

local function check_ancestors(modname, code, data, ancestors, is_etymology_language)
	if type(ancestors) == "string" then ancestors = mw.text.split(ancestors, "%s*,%s*") end
	
	local canonical_name = data[1]
	for _, ancestor_code in ipairs(ancestors) do
		if not (m_language_data[ancestor_code] or m_etym_language_data[ancestor_code]) then
			discrepancy(modname,
				"%s (<code>%s</code>) lists an invalid language code <code>%s</code> as ancestor.",
				link(canonical_name), code, ancestor_code)
		end
	end
end

-- Just trying to not have a module error when someone puts a script code
-- in the position of a language code.
local function show_family_code(code)
	if type(code) == "string" then
		return "<code>" .. code .. "</code>"
	else
		return require("Module:debug").highlight_dump(code)
	end
end

local function check_languages()
	local check_language_data_keys = check_data_keys{
		1, 2, 3, 4, -- canonical name, wikidata item, family, scripts
		"display_text", "generate_forms", "entry_name", "sort_key",
		"otherNames", "aliases", "varieties",
		"type", "ancestors",
		"wikimedia_codes", "wikipedia_article", "standardChars",
		"translit", "override_translit", "link_tr",
		"dotted_dotless_i"
	}
	
	local function check_language(modname, code, data, mainData, extraData)
		local canonical_name, lang_type = data[1], data.type
		
		check_language_data_keys(modname, code, data)
		
		if all_codes[code] then
			discrepancy(modname, "Code <code>%s</code> is not unique; it is also defined in [[Module:%s]].", code, all_codes[code])
		else
			if not m_language_codes[code] then
				discrepancy("languages/code to canonical name", "The code <code>%s</code> (%s) is missing.", code, canonical_name)
			end
			all_codes[code] = modname
		end
		
		if not canonical_name then
			discrepancy(modname, "Code <code>%s</code> has no canonical name specified.", code)
		elseif language_names[canonical_name] then
			discrepancy(modname,
				"%s (<code>%s</code>) has a canonical name that is not unique; it is also used by the code <code>%s</code>.",
				link(canonical_name), code, language_names[canonical_name])
		else
			if not m_language_canonical_names[canonical_name] then
				discrepancy("languages/canonical names", "The canonical name %s (<code>%s</code>) is missing.", canonical_name, code)
			end
			language_names[canonical_name] = code
		end
		
		check_wikidata_item(modname, code, data, 2)

		if extraData then
			check_other_names_aliases_varieties(modname, code, canonical_name, extraData)
		end
		
		if lang_type and not (lang_type == "regular" or lang_type == "reconstructed" or lang_type == "appendix-constructed") then
			discrepancy(modname, "%s (<code>%s</code>) is of an invalid type <code>%s</code>.", link(canonical_name), code, data.type)
		end
		
		if mainData.aliases then
			discrepancy(modname, "%s (<code>%s</code>) has the <code>aliases</code> key. This must be moved to [[Module:" .. modname .. "/extra]].", link(canonical_name), code)
		end
		
		if mainData.varieties then
			discrepancy(modname, "%s (<code>%s</code>) has the <code>varieties</code> key. This must be moved to [[Module:" .. modname .. "/extra]].", link(canonical_name), code)
		end
		
		if mainData.otherNames then
			discrepancy(modname, "%s (<code>%s</code>) has the <code>otherNames</code> key. This must be moved to [[Module:" .. modname .. "/extra]].", link(canonical_name), code)
		end
		
		if not extraData then
			discrepancy(modname .. "/extra", "%s (<code>%s</code>) has data in [[Module:" .. modname .. "]], but does not have corresponding data in [[Module:" .. modname .. "/extra]].", link(canonical_name), code)
		--elseif extraData.otherNames then
		--	discrepancy(modname .. "/extra", "%s (<code>%s</code>) has <code>otherNames</code> key, but these should be changed to either <code>aliases</code> or <code>varieties</code>.", link(canonical_name), code)
		end
		
		local sc = data[4]
		if sc then
			if type(sc) == "string" then
				sc = mw.text.split(sc, "%s*,%s*")
			end
			if type(sc) == "table" then
				if not sc[1] then
					discrepancy(modname, "%s (<code>%s</code>) has no scripts listed.", link(canonical_name), code)
				else
					for _, sccode in ipairs(sc) do
						local cur_sc = m_script_data[sccode]
						if not cur_sc and sccode ~= "All" then
							discrepancy(modname,
								"%s (<code>%s</code>) lists an invalid script code <code>%s</code>.",
								link(canonical_name), code, sccode)
						-- elseif not cur_sc.characters then
						-- 	discrepancy(modname,
						-- 		"%s (<code>%s</code>) lists a script without characters <code>%s</code> (%s).",
						-- 		link(canonical_name), code, sccode, cur_sc[1])
						end
			
						nonempty_scripts[sccode] = true
					end
				end
			else
				discrepancy(modname,
					"The %s field for %s (<code>%s</code>) must be a table or string.",
					4, link(canonical_name), code)
			end
		end
		
		if data.ancestors then
			check_ancestors(modname, code, data, data.ancestors, false)
		end
		
		if data[3] then
			local family = data[3]
			if not m_family_data[family] then
				discrepancy(modname,
					"%s (<code>%s</code>) has an invalid family code %s.",
					link(canonical_name), code, show_family_code(family))
			end
			
			nonempty_families[family] = true
		end
		
		if data.sort_key then
			check_entry_name_or_sortkey(modname, code, data, "sort_key")
		end
		
		if data.entry_name then
			check_entry_name_or_sortkey(modname, code, data, "entry_name")
		end

		if data.display then
			check_entry_name_or_sortkey(modname, code, data, "display")
		end

		if data.standardChars then
			if type(data.standardChars) == "table" then
				local sccodes = {}
				for _, sccode in ipairs(sc) do
					sccodes[sccode] = true
				end
				for sccode in pairs(data.standardChars) do
					if not (sccodes[sccode] or sccode == 1) then
						discrepancy(modname, "The field %s in the standardChars table for %s (<code>%s</code>) does not match any script for that language.",
							sccode, canonical_name, code)
					end
				end
			elseif data.standardChars and type(data.standardChars) ~= "string" then
				discrepancy(modname, "The standardChars field in the data table for %s (<code>%s</code>) must be a string or table.",
					canonical_name, code)
			end
		end
		
		check_true_or_nil(modname, code, data, "override_translit")
		check_true_or_nil(modname, code, data, "link_tr")
		
		if data.override_translit and not data.translit then
			discrepancy(modname,
				"%s (<code>%s</code>) has <code>override_translit</code> set, but no transliteration module",
				link(canonical_name), code)
		end
	end
	
	-- Check two-letter codes
	local modname = "languages/data/2"
	local data2 = mw.loadData("Module:" .. modname)
	local extradata2 = mw.loadData("Module:" .. modname .. "/extra")
	
	for code, data in pairs(data2) do
		if not code:find("^[a-z][a-z]$") then
			discrepancy(modname, '%s (<code>%s</code>) does not have a two-letter code.', link(data[1]), code)
		end
		
		check_language(modname, code, data, data2[code], extradata2[code])
	end
	
	-- Check three-letter codes
	for i = string.byte('a'), string.byte('z') do
		local letter = string.char(i)
		local modname = "languages/data/3/" .. letter
		local data3 = mw.loadData("Module:" .. modname)
		local extradata3 = mw.loadData("Module:" .. modname .. "/extra")
		local code_pattern = "^" .. letter .. "[a-z][a-z]$"
		
		for code, data in pairs(data3) do
			if not code:find(code_pattern) then
				discrepancy(modname,
					'%s (<code>%s</code>) does not have a three-letter code starting with "<code>%s</code>".',
					link(data[1]), code, letter)
			end
			
			check_language(modname, code, data, data3[code], extradata3[code])
		end
	end
	
	-- Check exceptional codes
	modname = "languages/data/exceptional"
	local datax = mw.loadData("Module:" .. modname)
	local extradatax = mw.loadData("Module:" .. modname .. "/extra")
	
	for code, data in pairs(datax) do
		if code:find("^[a-z][a-z][a-z]?$") then
			discrepancy(modname, '%s (<code>%s</code>) has a two- or three-letter code.', link(data[1]), code)
		end
		
		check_language(modname, code, data, datax[code], extradatax[code])
	end
	
	-- These checks must be done while all_codes only contains language codes:
	-- that is, after language data modules have been processed, but before
	-- etymology languages, families, and scripts have.
	local function check_code_and_name(modname, code, canonical_name)
		if not all_codes[code] then
			if not language_names[canonical_name] then
				discrepancy(modname,
					"The code <code>%s</code> and the canonical name %s should be removed; they are not found in a submodule of [[Module:languages]].",
					code, canonical_name)
			else
				discrepancy(modname,
					"<code>%s</code>, the code for the canonical name %s, is wrong; it should be <code>%s</code>.",
					code, canonical_name, language_names[canonical_name])
			end
		elseif not language_names[canonical_name] then
			local data_table = require("Module:" .. all_codes[code])[code]
			discrepancy(modname,
				"%s, the canonical name for the code <code>%s</code>, is wrong; it should be %s.",
				canonical_name, code, data_table[1])
		end
	end
	
	for code, canonical_name in pairs(m_language_codes) do
		check_code_and_name("languages/code to canonical name", code, canonical_name)
	end
	
	for canonical_name, code in pairs(m_language_canonical_names) do
		check_code_and_name("languages/canonical names", code, canonical_name)
	end
	
	-- Check [[Template:langname-lite]]
	local frame = mw.getCurrentFrame()
	local content = mw.title.new("Template:langname-lite"):getContent()
	content = content:gsub("%<%!%-%-.-%-%-%>", "") -- remove comments
	local match = mw.ustring.gmatch(content, "\n\t*|#*([^\n]+)=([^\n]*)")
	while true do
		local code, name, check_name = match()
		if not code then return "OK" end
		if code:len() > 1 and code ~= "default" then
			for _, code in pairs(mw.text.split(code, "|")) do
				local lang = m_languages.getByCode(code, nil, true, true)
				if name:match("etymcode") then
					local nonEtym_name = frame:preprocess(name)
					local nonEtym_real_name = lang:getNonEtymologicalName()
					if nonEtym_name ~= nonEtym_real_name then
						discrepancy("Template:langname-lite", "Code: <code>" .. code .. "</code>. Saw name: " .. nonEtym_name .. ". Expected name: " .. nonEtym_real_name .. ".")
					end
					name = frame:preprocess(name:gsub("{{{allow etym|}}}", "1"))
				elseif name:match("familycode") then
					name = name:match("familycode|(.-)|")
				else
					name = name
				end
				if not lang then
					discrepancy("Template:langname-lite", "Code: <code>" .. code .. "</code>. Saw name: " .. name .. ". Language not present in data.")
				else
					local real_name = lang:getCanonicalName()
					if name ~= real_name then
						discrepancy("Template:langname-lite", "Code: <code>" .. code .. "</code>. Saw name: " .. name .. ". Expected name: " .. real_name .. ".")
					end
				end
			end
		end
	end
end

local function check_etym_languages()
	local modname = "etymology languages/data"
	
	local check_etymology_language_data_keys = check_data_keys{
		1, 2, 3, 4, 5, -- canonical name, wikidata item, family, scripts, parent
		"display_text", "generate_forms", "entry_name", "sort_key",
		"otherNames", "aliases", "varieties",
		"type", "main_code", "ancestors",
		"wikimedia_codes", "wikipedia_article", "standardChars",
		"translit", "override_translit", "link_tr",
		"dotted_dotless_i"
	}
	
	local function link(name)
		if not name then
			return "???"
		elseif name:find("[Ll]anguage$") then
			return name
		else
			return name .. " language"
		end
	end
	
	for code, data in pairs(m_etym_language_data) do
		local canonical_name, parent =
			data[1], data[5]
		check_etymology_language_data_keys(modname, code, data)
		
		if all_codes[code] then
			discrepancy(modname, "Code <code>%s</code> is not unique; it is also defined in [[Module:%s]].", code, all_codes[code])
		else
			if not m_etym_language_codes[code] then
				discrepancy("etymology languages/code to canonical name", "The code <code>%s</code> (%s) is missing.", code, canonical_name)
			end
			all_codes[code] = modname
		end
		
		if not canonical_name then
			discrepancy(modname, "Code <code>%s</code> has no canonical name specified.", code)
		elseif language_names[canonical_name] and data.main_code ~= m_languages.getByCanonicalName(canonical_name, nil, true):getCode() then
			discrepancy(modname,
				"%s (<code>%s</code>) has a canonical name that is not unique; it is also used by the code <code>%s</code>.",
				link(canonical_name), code, language_names[canonical_name])
		else
			if not m_etym_language_canonical_names[canonical_name] then
				discrepancy("etymology languages/canonical names", "The canonical name %s (<code>%s</code>) is missing.", canonical_name, code)
			end
			language_names[canonical_name] = code
		end
		
		check_other_names_aliases_varieties(modname, code, canonical_name, data)
		
		if parent then
			if type(parent) ~= "string" then
				discrepancy(modname,
					"Etymology-only %s (<code>%s</code>) has a parent language or family code that is %s rather than a string.",
					link(canonical_name), code, parent == nil and "nil" or "a " .. type(parent))
			elseif not (m_language_data[parent] or m_family_data[parent] or m_etym_language_data[parent]) then
				discrepancy(modname,
					"Etymology-only %s (<code>%s</code>) has invalid parent language or family code <code>%s</code>.",
					link(canonical_name), code, parent)
			end
			nonempty_families[parent] = true
		else
			discrepancy(modname,
				"Etymology-only %s (<code>%s</code>) has no parent language or family code.",
				link(canonical_name), code)
		end
		
		if data.ancestors then
			check_ancestors(modname, code, data, data.ancestors, false)
		end
		
		if data[3] then
			local family = data[3]
			if not m_family_data[family] then
				discrepancy(modname,
					"%s (<code>%s</code>) has an invalid family code %s.",
					link(canonical_name), code, show_family_code(family))
			end
			nonempty_families[family] = true
		end
		
		check_wikidata_item(modname, code, data, 2)
	end

	local checked = {}
	for code, data in pairs(m_etym_language_data) do
		local stack = {}

		while data do
			if checked[data] then
				break	
			end
			if stack[data] then
				discrepancy(modname, "%s (<code>%s</code>) has a cyclic parental relationship to %s (<code>%s</code>)",
					link(data[1]), code,
					link(m_etym_language_data[data[5]][1]), data.parent or data[5]
				)
				break
			end
			stack[data] = true
			code, data = data[5], data[5] and m_etym_language_data[data[5]]
		end
		
		for data in pairs(stack) do
			checked[data] = true	
		end
	end
	
	local function check_code_and_name(modname, code, canonical_name)
		if not all_codes[code] then
			if not language_names[canonical_name] then
				discrepancy(modname,
					"The code <code>%s</code> and the canonical name %s should be removed; they are not found in [[Module:etymology languages/data]].",
					code, canonical_name)
			else
				discrepancy(modname,
					"<code>%s</code>, the code for the canonical name %s, is wrong; it should be <code>%s</code>.",
					code, canonical_name, language_names[canonical_name])
			end
		elseif not language_names[canonical_name] then
			local data_table = require("Module:" .. all_codes[code])[code]
			discrepancy(modname,
				"%s, the canonical name for the code <code>%s</code>, is wrong; it should be %s.",
				canonical_name, code, data_table[1])
		end
	end
	
	for code, canonical_name in pairs(m_etym_language_codes) do
		check_code_and_name("etymology languages/code to canonical name", code, canonical_name)
	end
	
	for canonical_name, code in pairs(m_etym_language_canonical_names) do
		check_code_and_name("etymology languages/canonical names", code, canonical_name)
	end
end

local function check_families()
	local modname = "families/data"
	
	local check_family_data_keys = check_data_keys{
		1, 2, 3, -- canonical name, wikidata item, (parent) family
		"type",
		"protoLanguage", "otherNames", "aliases", "varieties",
	}

	local function link(name)
		if not name then
			return "???"
		elseif name:find("[Ll]anguages$") then
			return "[[:Category:" .. name .. "|" .. name .. " family]]"
		else
			return "[[:Category:" .. name .. " languages|" .. name .. " family]]"
		end
	end
	
	for code, data in pairs(m_family_data) do
		check_family_data_keys(modname, code, data)
		
		local canonical_name, family = data[1], data[3]
		
		if all_codes[code] then
			discrepancy(modname, "Code <code>%s</code> is not unique; it is also defined in [[Module:%s]].", code, all_codes[code])
		else
			if not m_family_codes[code] then
				discrepancy("families/code to canonical name", "The code <code>%s</code> (%s) is missing.", code, canonical_name)
			end
			all_codes[code] = modname
		end
		
		if not canonical_name then
			discrepancy(modname, "Code <code>%s</code> has no canonical name specified.", code)
		elseif family_names[canonical_name] then
			discrepancy(modname,
				"%s (<code>%s</code>) has a canonical name that is not unique; it is also used by the code <code>%s</code>.",
				link(canonical_name), code, family_names[canonical_name])
		else
			if not m_family_canonical_names[canonical_name] then
				discrepancy("families/canonical names", "The canonical name %s (<code>%s</code>) is missing.", canonical_name, code)
			end
			family_names[canonical_name] = code
		end
		
		if data[2] and type(data[2]) ~= "number" then
			discrepancy(modname, "%s (<code>%s</code>) has a wikidata item value that is not a number or <code>nil</code>: %s", link(canonical_name), code, mw.dumpObject(data[2]))
		end
		
		check_other_names_aliases_varieties(modname, code, canonical_name, data)
		
		if family then
			if family == code and code ~= "qfa-not" then
				discrepancy(modname,
					"%s (<code>%s</code>) has itself as its family.",
					link(canonical_name), code)
			elseif not m_family_data[family] then
				discrepancy(modname,
					"%s (<code>%s</code>) has an invalid parent family code %s.",
					link(canonical_name), code, show_family_code(family))
			end
			
			nonempty_families[family] = true
		end
		
		check_wikidata_item(modname, code, data, 2)
	end
	
	for code, data in pairs(m_family_data) do
		if not (nonempty_families[code] or allowed_empty_families[code]) then
			discrepancy(modname, "%s (<code>%s</code>) has no child families or languages.", link(data[1]), code)
		end
	end

	local checked = { ['qfa-not'] = true }
	for code, data in pairs(m_family_data) do
		local stack = {}

		while data do
			if checked[code] then
				break	
			end
			if stack[code] then
				discrepancy(modname, "%s (<code>%s</code>) has a cyclic parental relationship to %s (<code>%s</code>)",
					link(data[1]), code,
					link(m_family_data[data[3]][1]), data[3]
				)
				break
			end
			stack[code] = true
			code, data = data[3], m_family_data[data[3]]
		end
		
		for code in pairs(stack) do
			checked[code] = true	
		end
	end
end

local function check_scripts()
	local modname = "scripts/data"
	
	local check_script_data_keys = check_data_keys({
		1, 2, -- canonical name, writing systems
		"canonicalName", "otherNames", "aliases", "varieties", "parent",
		"wikipedia_article", "characters", "spaces", "capitalized", "translit", "direction",
		"character_category", "normalizationFixes"
	}, true)
	
	local m_script_codes = require('Module:scripts/code to canonical name')
	local m_script_canonical_names = require('Module:scripts/by name')
	
	for code, data in pairs(m_script_data) do
		local canonical_name = data[1]
		if not m_script_codes[code] and #code == 4 then
			discrepancy('scripts/code to canonical name', '<code>%s</code> (%s) is missing', code, canonical_name)
		end
		
		check_script_data_keys(modname, code, data)
		
		if not canonical_name then
			discrepancy(modname, "Code <code>%s</code> has no canonical name specified.", code)
		elseif script_names[canonical_name] then
			--[=[
			discrepancy(modname,
				"%s (<code>%s</code>) has a canonical name that is not unique; it is also used by the code <code>%s</code>.",
				link_script(data.names[1]), code, script_names[data.names[1]])
			--]=]
		else
			if not m_script_canonical_names[canonical_name] and #code == 4 then
				discrepancy('scripts/by name', '%s (<code>%s</code>) is missing', canonical_name, code)
			end
			script_names[canonical_name] = code
		end
		
		check_other_names_aliases_varieties(modname, code, canonical_name, data)
		
		if not nonempty_scripts[code] then
			discrepancy(modname,
				"%s (<code>%s</code>) is not used by any language%s.",
				link_script(canonical_name), code, data.characters and ""
					or " and has no characters listed for auto-detection")
		--[[
		elseif not data.characters then
			discrepancy(modname, "%s (<code>%s</code>) has no characters listed for auto-detection.", link_script(canonical_name), code)
		--]]
		end

		if data.characters then
			validate_pattern(data.characters, modname, code, data, false)
		end
	end
	
	local function check_code_and_name(modname, code, canonical_name)
		if not m_script_codes[code] then
			if not script_names[canonical_name] then
				discrepancy(modname,
					"The code <code>%s</code> and the canonical name %s should be removed; they are not found in a submodule of [[Module:scripts]].",
					code, canonical_name)
			else
				discrepancy(modname,
					"<code>%s</code>, the code for the canonical name %s, is wrong; it should be <code>%s</code>.",
					code, canonical_name, script_names[canonical_name])
			end
		elseif not script_names[canonical_name] then
			local data_table = require("Module:scripts/data")[code]
			discrepancy(modname,
				"%s, the canonical name for the code <code>%s</code>, is wrong; it should be %s.",
				canonical_name, code, data_table[1])
		end
	end
	
	for code, canonical_name in pairs(m_script_codes) do
		check_code_and_name("scripts/code to canonical name", code, canonical_name)
	end
	
	for canonical_name, code in pairs(m_script_canonical_names) do
		check_code_and_name("scripts/by name", code, canonical_name)
	end	
end

local function check_labels()
	local check_label_data_keys = check_data_keys{
		"display", "Wikipedia", "glossary",
		"plain_categories", "topical_categories", "pos_categories", "regional_categories", "sense_categories",
		"omit_preComma", "omit_postComma", "omit_preSpace",
		"deprecated", "track"
	}
	
	local function check_label(modname, code, data)
		local typ = type(data)
		if typ == "table" then
			check_label_data_keys(modname, code, data)
		elseif typ ~= "string" then
			discrepancy(modname,
				"The data for label <code>%s</code> is a %s; only tables and strings are allowed.",
				code, typ)
		end
	end
	
	for _, module in ipairs{"", "/regional", "/topical"} do
		local modname = "Module:labels/data" .. module
		module = require(modname)
		for label, data in pairs(module) do
			check_label(modname, label, data)
		end
	end
	
	for code in pairs(m_language_codes) do
		local modname = "Module:labels/data/lang/" .. code
		local ok, module = pcall(require, modname)
		if ok then
			for label, data in pairs(module) do
				check_label(modname, label, data)
			end
		end
	end
end

local function check_zh_trad_simp()
	local m_ts = mw.loadData("Module:zh/data/ts")
	local m_st = mw.loadData("Module:zh/data/st")
	local ruby = require("Module:ja-ruby").ruby_auto
	local lang = m_languages.getByCode("zh")
	local Hant = m_scripts.getByCode("Hant")
	local Hans = m_scripts.getByCode("Hans")
	
	local data = {[0] = m_st.st, m_ts.ts}
	local mod = {[0] = "st", "ts"}
	local var = {[0] = "Simp.", "Trad."}
	local sc = {[0] = Hans, Hant}
	
	local function find_stable_loop(chars, other, j)
		local display = ruby({["markup"] = "[" .. other .. "](" .. var[(j+1)%2] .. ")"})
		display = m_links.language_link({term = other, alt = display, lang = lang, sc = sc[(j+1)%2], tr = "-"}, false)
		table.insert(chars, display)
		if data[(j+1)%2][other] == other then
			table.insert(chars, other)
			return chars, 1
		elseif not data[(j+1)%2][other] then
			table.insert(chars, "not found")
			return chars, 2
		elseif data[j%2][data[(j+1)%2][other]] ~= other then
			return find_stable_loop(chars, data[(j+1)%2][other], j + 1)
		else
			local display = ruby({["markup"] = "[" .. data[(j+1)%2][other] .. "](" .. var[j%2] .. ")"})
			display = m_links.language_link({term = data[(j+1)%2][other], alt = display, lang = lang, sc = sc[j%2], tr = "-"}, false)
			table.insert(chars, display .. " (")
			display = ruby({["markup"] = "[" .. data[j%2][data[(j+1)%2][other]] .. "](" .. var[(j+1)%2] .. ")"})
			display = m_links.language_link({term = data[j%2][data[(j+1)%2][other]], alt = display, lang = lang, sc = sc[(j+1)%2], tr = "-"}, false)
			table.insert(chars, display .. " etc.)")
			return chars, 3
		end
		
		return chars, issue
	end
	
	for i = 0, 1, 1 do
		for char, other in pairs(data[i]) do
			if data[(i+1)%2][other] ~= char then
				local chars, issue = {}
				local display = ruby({["markup"] = "[" .. char .. "](" .. var[i] .. ")"})
				display = m_links.language_link({term = char, alt = display, lang = lang, sc = sc[i], tr = "-"}, false)
				table.insert(chars, display)
				chars, issue = find_stable_loop(chars, other, i)
				if issue == 1 or issue == 2 then
					local sc_this, mod_this, j = {}
					if chars[#chars-1]:match(var[(i+1)%2]) then
						j = 1
					else
						j = 0
					end
					mod_this = mod[(i+j)%2]
					sc_this = {[0] = sc[(i+j)%2], sc[(i+j+1)%2]}
					for k, char in ipairs(chars) do
						chars[k] = m_script_utils.tag_text(char, lang, sc_this[k%2], "term")
					end
					if issue == 1 then
						discrepancy("zh/data/" .. mod_this, "character references itself: " .. table.concat(chars, " → "))
					elseif issue == 2 then
						discrepancy("zh/data/" .. mod_this, "missing character: " .. table.concat(chars, " → "))
					end
				elseif issue == 3 then
					for j, char in ipairs(chars) do
						chars[j] = m_script_utils.tag_text(char, lang, sc[(i+j)%2], "term")
					end
					discrepancy("zh/data/" .. mod[i], "possible mismatched character: " .. table.concat(chars, " → "))
				end
			end
		end
	end
end

local function check_serialization(modname)
	local serializers = {
		["Hani-sortkey/data/serialized"] = "Hani-sortkey/serializer",
		["zh/data/ts/serialized"] = "zh/data/ts/serializer",
		["zh/data/st/serialized"] = "zh/data/st/serializer",
	}
	
	if not serializers[modname] then
		return nil
	end
	
	local serializer = serializers[modname]
	local current_data = require("Module:" .. serializer).main(true)
	local stored_data = require("Module:" .. modname)
	if current_data ~= stored_data then
		discrepancy(modname, "<strong><u>Important!</u> Serialized data is out of sync. Use [[Module: ".. serializer .. "]] to update it. If you have made any changes to the underlying data, the serialized data <u>must</u> be updated before these changes will take effect.</strong>")
	end
end

-- Warning: cannot be called twice in the same module invocation because
-- some module-global variables are not reset between calls.
function export.do_checks(modules)
	messages = setmetatable({}, {
		__index = function (self, k)
			local val = Array()
			self[k] = val
			return val
		end
	})
	
	if modules["zh/data/ts"] or modules["zh/data/st"] then
		check_zh_trad_simp()
	end
	check_languages()
	check_etym_languages()

	-- families and scripts must be checked AFTER languages; languages checks fill out
	-- the nonempty_families and nonempty_scripts tables, used for testing if a family/script
	-- is ever used in the data
	check_families()
	check_scripts()
	
	if modules["labels/data"] then
		check_labels()
	end
	
	for module in pairs(modules) do
		check_serialization(module)
	end
	
	setmetatable(messages, nil)
	
	local function find_code(message)
		return string.match(message, "<code>([^<]+)</code>")
	end
	
	find_code = require("Module:fun").memoize(find_code)
	
	local function comp(message1, message2)
		local code1, code2 = find_code(message1), find_code(message2)
		if code1 and code2 then
			return code1 < code2
		else
			return message1 < message2
		end
	end
	
	for modname, msglist in pairs(messages) do
		msglist:sort(comp)
	end
	
	local ret = messages
	messages = nil
	return ret
end

function export.format_message(modname, msglist)
	local header; if modname:match("^Module:") or modname:match("^Template:") then
		header = "===[[" .. modname .. "]]==="
	else
		header = "===[[Module:" .. modname .. "]]==="
	end
	return header
		.. msglist
			:map(
				function(msg)
					return "\n* " .. msg
				end)
			:concat()
end

function export.check_modules(args)
	
	local modules = {}
	for i, arg in ipairs(args) do
		modules[arg] = true
	end
	
	local ret = Array()
	local messages = export.do_checks(modules)
	
	for _, module in ipairs(args) do
		local msglist = messages[module]
		if msglist then
			ret:insert(export.format_message(module, msglist))
		end
	end
	return ret:concat("\n")
end

function export.check_modules_t(frame)
	local args = m_table.shallowcopy(frame.args)
	return export.check_modules(args)
end

function export.perform(frame)
	local messages = export.do_checks({})
	
	-- Format the messages
	local ret = Array()
	for modname, msglist in m_table.sortedPairs(messages) do
		ret:insert(export.format_message(modname, msglist))
	end
	
	-- Are there any messages?
	if i == 1 then
		return '<b class="success">Glory to Arstotzka.</b>'
	else
		ret:insert(1, '<b class="warning">Discrepancies detected:</b>')
		
		return ret:concat('\n')
	end
end

return export