From patchwork Thu Mar 24 16:51:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Hostetler X-Patchwork-Id: 12790905 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0540C433EF for ; Thu, 24 Mar 2022 16:53:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352060AbiCXQyg (ORCPT ); Thu, 24 Mar 2022 12:54:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351931AbiCXQxz (ORCPT ); Thu, 24 Mar 2022 12:53:55 -0400 Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [IPv6:2a00:1450:4864:20::330]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57DA9B0D28 for ; Thu, 24 Mar 2022 09:51:59 -0700 (PDT) Received: by mail-wm1-x330.google.com with SMTP id bi13-20020a05600c3d8d00b0038c2c33d8f3so7577020wmb.4 for ; Thu, 24 Mar 2022 09:51:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=E8xmQ7dYip7SaSRf9IXmrYL6K0sMohTDrDq1DYcKE54=; b=B8XZ3CQrh8kkU7+5rkf09okzMxXj4oEMRSU/7TBsx0Cqvntld+82b6mcBy3m+t84r6 TxCW1YtaQc58VZ8/Z6K3h+nrtUsggNORAn56e448k6QCysSZnnLxIzF1zXZllbpFXr3I dKWUTyGCp00IFpFFcYi63sw2GQbUbDCHhRNsxzVP1OZ7Pm/zYygmr2/tW7bqJsuezm/6 2WgZSPdQKIyrnenf5S5g/WV/uOZf41RkXHyK3KukroGhGkoNydt1jaEDjPD/EZf7GENB cj1vweBdzvQ+htEicwupA8UPBISdDyudIZj2A9NwR4zNgyS/i5Axqcpalqd8iGb/wI3k 8FNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=E8xmQ7dYip7SaSRf9IXmrYL6K0sMohTDrDq1DYcKE54=; b=CZ6Xr3gYe6+ZX7ssUeMwd1KvT4vkoE1X5oZCb/If8j0/M/5HPTx4k12rX9waDNAGpm l3aYP9qGv9SwXZJhv7/2hDVBvMHS5UoAIJzueW8txk+AlQfYbBc9P9VGOPjxIf3oAnyb JTviB0Zyacfrkj4S9q7AexGofnD7pba+v7VTx+snlaFSPzNANZByr71jo2q/yY6T12Ta 62xSawyyQ/Ib32kc48+5TkTlHih61jkbpWlghkcYcPcp6Ehe8lTbNq/1yok61r5B1sC2 1Fk2BNs/TKA3NEsEyVMx/gUI9djWYCKTI/aUAlIYM6qU5rwlwgq4BOX3xKSeQCyv8VH0 75CA== X-Gm-Message-State: AOAM531pqMKp3wIyhJnvTBlwlAhIrWXlh8xELlrZ5YTVuiZC1F7ebhCn qLeJnQkzUi0JJEzgHLqm11BxgyndfW0= X-Google-Smtp-Source: ABdhPJzV+BnD9K4yQAy65bpX4QoNstaNfBrvJxNOqebPvkHKzf9irm0JsyoRpESM69TDIQ/0wgoSUw== X-Received: by 2002:a05:600c:1552:b0:38c:de92:6a2f with SMTP id f18-20020a05600c155200b0038cde926a2fmr1045906wmg.152.1648140717630; Thu, 24 Mar 2022 09:51:57 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id c24-20020a7bc018000000b0038a18068cf5sm6339958wmb.15.2022.03.24.09.51.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Mar 2022 09:51:56 -0700 (PDT) Message-Id: In-Reply-To: References: Date: Thu, 24 Mar 2022 16:51:19 +0000 Subject: [PATCH v4 26/27] t/lib-unicode-nfc-nfd: helper prereqs for testing unicode nfc/nfd Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: Jeff Hostetler , Derrick Stolee , =?utf-8?b?w4Z2YXIgQXJuZmrDtnI=?= =?utf-8?b?w7A=?= Bjarmason , Torsten =?unknown-8bit?q?B?= =?unknown-8bit?q?=C3=B6gershausen?= , rsbecker@nexbridge.com, Jeff Hostetler , Jeff Hostetler Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Jeff Hostetler From: Jeff Hostetler Create a set of prereqs to help understand how file names are handled by the filesystem when they contain NFC and NFD Unicode characters. Signed-off-by: Jeff Hostetler --- t/lib-unicode-nfc-nfd.sh | 167 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) create mode 100755 t/lib-unicode-nfc-nfd.sh diff --git a/t/lib-unicode-nfc-nfd.sh b/t/lib-unicode-nfc-nfd.sh new file mode 100755 index 00000000000..cf9c26d1e22 --- /dev/null +++ b/t/lib-unicode-nfc-nfd.sh @@ -0,0 +1,167 @@ +# Help detect how Unicode NFC and NFD are handled on the filesystem. + +# A simple character that has a NFD form. +# +# NFC: U+00e9 LATIN SMALL LETTER E WITH ACUTE +# UTF8(NFC): \xc3 \xa9 +# +# NFD: U+0065 LATIN SMALL LETTER E +# U+0301 COMBINING ACUTE ACCENT +# UTF8(NFD): \x65 + \xcc \x81 +# +utf8_nfc=$(printf "\xc3\xa9") +utf8_nfd=$(printf "\x65\xcc\x81") + +# Is the OS or the filesystem "Unicode composition sensitive"? +# +# That is, does the OS or the filesystem allow files to exist with +# both the NFC and NFD spellings? Or, does the OS/FS lie to us and +# tell us that the NFC and NFD forms are equivalent. +# +# This is or may be independent of what type of filesystem we have, +# since it might be handled by the OS at a layer above the FS. +# Testing shows on MacOS using APFS, HFS+, and FAT32 reports a +# collision, for example. +# +# This does not tell us how the Unicode pathname will be spelled +# on disk, but rather only that the two spelling "collide". We +# will examine the actual on disk spelling in a later prereq. +# +test_lazy_prereq UNICODE_COMPOSITION_SENSITIVE ' + mkdir trial_${utf8_nfc} && + mkdir trial_${utf8_nfd} +' + +# Is the spelling of an NFC pathname preserved on disk? +# +# On MacOS with HFS+ and FAT32, NFC paths are converted into NFD +# and on APFS, NFC paths are preserved. As we have established +# above, this is independent of "composition sensitivity". +# +# 0000000 63 5f c3 a9 +# +# (/usr/bin/od output contains different amount of whitespace +# on different platforms, so we need the wildcards here.) +# +test_lazy_prereq UNICODE_NFC_PRESERVED ' + mkdir c_${utf8_nfc} && + ls | od -t x1 | grep "63 *5f *c3 *a9" +' + +# Is the spelling of an NFD pathname preserved on disk? +# +# 0000000 64 5f 65 cc 81 +# +test_lazy_prereq UNICODE_NFD_PRESERVED ' + mkdir d_${utf8_nfd} && + ls | od -t x1 | grep "64 *5f *65 *cc *81" +' + mkdir c_${utf8_nfc} && + mkdir d_${utf8_nfd} && + +# The following _DOUBLE_ forms are more for my curiosity, +# but there may be quirks lurking when there are multiple +# combining characters in non-canonical order. + +# Unicode also allows multiple combining characters +# that can be decomposed in pieces. +# +# NFC: U+1f67 GREEK SMALL LETTER OMEGA WITH DASIA AND PERISPOMENI +# UTF8(NFC): \xe1 \xbd \xa7 +# +# NFD1: U+1f61 GREEK SMALL LETTER OMEGA WITH DASIA +# U+0342 COMBINING GREEK PERISPOMENI +# UTF8(NFD1): \xe1 \xbd \xa1 + \xcd \x82 +# +# But U+1f61 decomposes into +# NFD2: U+03c9 GREEK SMALL LETTER OMEGA +# U+0314 COMBINING REVERSED COMMA ABOVE +# UTF8(NFD2): \xcf \x89 + \xcc \x94 +# +# Yielding: \xcf \x89 + \xcc \x94 + \xcd \x82 +# +# Note that I've used the canonical ordering of the +# combinining characters. It is also possible to +# swap them. My testing shows that that non-standard +# ordering also causes a collision in mkdir. However, +# the resulting names don't draw correctly on the +# terminal (implying that the on-disk format also has +# them out of order). +# +greek_nfc=$(printf "\xe1\xbd\xa7") +greek_nfd1=$(printf "\xe1\xbd\xa1\xcd\x82") +greek_nfd2=$(printf "\xcf\x89\xcc\x94\xcd\x82") + +# See if a double decomposition also collides. +# +test_lazy_prereq UNICODE_DOUBLE_COMPOSITION_SENSITIVE ' + mkdir trial_${greek_nfc} && + mkdir trial_${greek_nfd2} +' + +# See if the NFC spelling appears on the disk. +# +test_lazy_prereq UNICODE_DOUBLE_NFC_PRESERVED ' + mkdir c_${greek_nfc} && + ls | od -t x1 | grep "63 *5f *e1 *bd *a7" +' + +# See if the NFD spelling appears on the disk. +# +test_lazy_prereq UNICODE_DOUBLE_NFD_PRESERVED ' + mkdir d_${greek_nfd2} && + ls | od -t x1 | grep "64 *5f *cf *89 *cc *94 *cd *82" +' + +# The following is for debugging. I found it useful when +# trying to understand the various (OS, FS) quirks WRT +# Unicode and how composition/decomposition is handled. +# For example, when trying to understand how (macOS, APFS) +# and (macOS, HFS) and (macOS, FAT32) compare. +# +# It is rather noisy, so it is disabled by default. +# +if test "$unicode_debug" = "true" +then + if test_have_prereq UNICODE_COMPOSITION_SENSITIVE + then + echo NFC and NFD are distinct on this OS/filesystem. + else + echo NFC and NFD are aliases on this OS/filesystem. + fi + + if test_have_prereq UNICODE_NFC_PRESERVED + then + echo NFC maintains original spelling. + else + echo NFC is modified. + fi + + if test_have_prereq UNICODE_NFD_PRESERVED + then + echo NFD maintains original spelling. + else + echo NFD is modified. + fi + + if test_have_prereq UNICODE_DOUBLE_COMPOSITION_SENSITIVE + then + echo DOUBLE NFC and NFD are distinct on this OS/filesystem. + else + echo DOUBLE NFC and NFD are aliases on this OS/filesystem. + fi + + if test_have_prereq UNICODE_DOUBLE_NFC_PRESERVED + then + echo Double NFC maintains original spelling. + else + echo Double NFC is modified. + fi + + if test_have_prereq UNICODE_DOUBLE_NFD_PRESERVED + then + echo Double NFD maintains original spelling. + else + echo Double NFD is modified. + fi +fi