Gettext and plural support for client-side translations (#14726)

---------

Co-authored-by: Ekdohibs <nathanael.courant@laposte.net>
Co-authored-by: y5nw <y5nw@protonmail.com>
Co-authored-by: rubenwardy <rw@rubenwardy.com>

games/devtest/mods/testtranslations/init.lua

@@ -0,0 +1,26 @@
+local S, NS = minetest.get_translator("testtranslations")
+
+local function send_compare(name, text)
+	core.chat_send_player(name, ("%s | %s | %s"):format(
+			core.get_translated_string("", text), text, core.get_translated_string("fr", text)))
+end
+
+minetest.register_chatcommand("testtranslations", {
+	params = "",
+	description = "Test translations",
+	privs = {},
+	func = function(name, param)
+		core.chat_send_player(name, "Please ensure your locale is set to \"fr\"")
+		core.chat_send_player(name, "Untranslated | Client-side translation | Server-side translation (fr)")
+		send_compare(name, S("Testing .tr files: untranslated"))
+		send_compare(name, S("Testing .po files: untranslated"))
+		send_compare(name, S("Testing .mo files: untranslated"))
+		send_compare(name, S("Testing fuzzy .po entry: untranslated (expected)"))
+		send_compare(name, core.translate("translation_po", "Testing .po without context: untranslated"))
+		send_compare(name, core.translate("translation_mo", "Testing .mo without context: untranslated"))
+		for i = 0,4 do
+			send_compare(name, NS("@1: .po singular", "@1: .po plural", i, tostring(i)))
+			send_compare(name, NS("@1: .mo singular", "@1: .mo plural", i, tostring(i)))
+		end
+	end
+})

games/devtest/mods/testtranslations/locale/testtranslations.fr.po

@@ -0,0 +1,9 @@
+# Dummy entry. This is a test to make sure that a parser error is not thrown
+# if the following line is msgctxt.
+msgctxt "testtranslations"
+msgid "Dummy entry"
+msgstr "Dummy result"
+
+# Used for translating the mod title
+msgid "Test translations"
+msgstr "Test translations (French)"

games/devtest/mods/testtranslations/locale/translation_po.fr.po

@@ -0,0 +1,22 @@
+# Test Plural-Forms parsing
+msgid ""
+msgstr ""
+"Plural-Forms: nplurals=2; plural= (n-1+1)<=1 ? n||1?0:1 : 1?(!!2):2;"
+
+msgctxt "testtranslations"
+msgid "Testing .po files: untranslated"
+msgstr "Testing .po files: translated"
+
+msgctxt "testtranslations"
+msgid "@1: .po singular"
+msgid_plural "@1: .po plural"
+msgstr[0] "@1: .po 0 and 1 (French singular)"
+msgstr[1] "@1: .po >1 (French plural)"
+
+#, foo bar fuzzy
+msgctxt "testtranslations"
+msgid "Testing fuzzy .po entry: untranslated (expected)"
+msgstr "Testing fuzzy .po entry: translated (wrong)"
+
+msgid "Testing .po without context: untranslated"
+msgstr "Testing .po without context: translated"

games/devtest/mods/testtranslations/locale/translation_tr.fr.tr

@@ -0,0 +1,2 @@
+# textdomain: testtranslations
+Testing .tr files: untranslated=Testing .tr files: translated

games/devtest/mods/testtranslations/mod.conf

@@ -0,0 +1,3 @@
+name = testtranslations
+title = Test translations
+description = Test mod to test translations.

games/devtest/mods/testtranslations/test_locale/readme.txt

@@ -0,0 +1,4 @@
+The translation files in this directory intentionally include errors (which
+would be reported when someone starts the devtest game in the de locale). This
+allows the unittest to check that the translation file reader also handles
+files that include errors.

games/devtest/mods/testtranslations/test_locale/translation_po.de.po

@@ -0,0 +1,42 @@
+# This file is used by the C++ unittest for testing the parser
+msgid ""
+msgstr "\n\n\n"
+"Plural-Forms: nplurals=2; plural=n!=1;"
+"\n\n\n"
+
+msgid  "foo"
+  msgstr "bar"  
+
+msgid "Untranslated"
+msgstr ""
+
+#, fuzzy
+msgid "Fuzzy entry"
+msgstr "Wrong"
+
+msgid "Multi\\""line\n"
+"string"
+msgstr "Multi\\\""  "li\\ne\nresult"
+
+msgctxt "Something" in "between"
+msgctxt "String does not end
+msgstr "Lost string"
+msgid "Wrong order"
+
+msgid "Singular form"
+msgid_plural "Plural form"
+msgstr[0] "Singular result"
+msgstr[1] "Plural result"
+
+msgid "Not enough value"
+msgid_plural "Not enough values"
+msgstr[0] "Result"
+
+msgid "Partial translation"
+msgid_plural "Partial translations"
+msgstr[0] "Partially translated"
+msgstr[1] ""
+
+msgctxt "context"
+msgid "With context"
+msgstr "Has context"

games/devtest/mods/testtranslations/translation_mo.de.po

@@ -0,0 +1,26 @@
+msgid ""
+msgstr "Plural-Forms: nplurals=2; plural= n != 1;"
+
+msgctxt "context"
+msgid "With context"
+msgstr "Has context"
+
+msgctxt "context"
+msgid "Singular form"
+msgid_plural "Plural form"
+msgstr[0] "Singular result"
+msgstr[1] "Plural result"
+
+# Replace plural form delimiter in the msgstr
+msgid "Corrupt singular"
+msgid_plural "Corrupt plural"
+msgstr[0] "Corrupt singular result"
+msgstr[1] "Corrupt plural result"
+
+# Replace terminating NUL in the MO file
+msgid "Corrupt entry"
+msgstr "Corrupted result"
+
+# Change the address of this entry to something invalid
+msgid "Removed entry"
+msgstr "Removed result"

games/devtest/mods/testtranslations/translation_mo.fr.po

@@ -0,0 +1,18 @@
+msgid ""
+msgstr ""
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=n>1;"
+
+msgctxt "testtranslations"
+msgid "Testing .mo files: untranslated"
+msgstr "Testing .mo files: translated"
+
+msgid "Testing .mo without context: untranslated"
+msgstr "Testing .mo without context: translated"
+
+msgctxt "testtranslations"
+msgid "@1: .mo singular"
+msgid_plural "@1: .mo plural"
+msgstr[0] "@1: .mo 0 and 1 (French singular)"
+msgstr[1] "@1: .mo >1 (French plural)"