From: Lars Schneider <larsxschneider@xxxxxxxxx> Hi, Patches 1-4, 6 are preparation and helper functions. Patch 5,7 are the actual change. This series depends on Torsten's 8462ff43e4 (convert_to_git(): safe_crlf/checksafe becomes int conv_flags, 2018-01-13) which is already in next. Changes since v5: * added 'core.checkRoundtripEncoding' to let the end user define a list of encodings for which Git performs conversion round trip checks (Junio's feedback) * add a test case for round trip conversions * move all round trip related changes into a new patch * rename has_missing_utf_bom() to is_missing_required_utf_bom() (Junio) * remove dead code in conversion round trip check (Junio) * use *.proj files instead of *.txt files as example (Torsten's feedback) * recommend explicitly setting the eol attribute if working-tree-encoding attribute is used (Torsten) * improve test case and check that 'git ls-files --eol' works as expected * rename variables from checkout_encoding to working_tree_encoding Thanks, Lars RFC: https://public-inbox.org/git/BDB9B884-6D17-4BE3-A83C-F67E2AFA2B46@xxxxxxxxx/ v1: https://public-inbox.org/git/20171211155023.1405-1-lars.schneider@xxxxxxxxxxxx/ v2: https://public-inbox.org/git/20171229152222.39680-1-lars.schneider@xxxxxxxxxxxx/ v3: https://public-inbox.org/git/20180106004808.77513-1-lars.schneider@xxxxxxxxxxxx/ v4: https://public-inbox.org/git/20180120152418.52859-1-lars.schneider@xxxxxxxxxxxx/ v5: https://public-inbox.org/git/20180129201855.9182-1-tboegi@xxxxxx/ Base Ref: Web-Diff: https://github.com/larsxschneider/git/commit/9e31832f3c Checkout: git fetch https://github.com/larsxschneider/git encoding-v6 && git checkout 9e31832f3c ### Interdiff (v5..v6): diff --git a/Documentation/config.txt b/Documentation/config.txt index 0e25b2c92b..d7a56054a5 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -530,6 +530,12 @@ core.autocrlf:: This variable can be set to 'input', in which case no output conversion is performed. +core.checkRoundtripEncoding:: + A comma separated list of encodings that Git performs UTF-8 round + trip checks on if they are used in an `working-tree-encoding` + attribute (see linkgit:gitattributes[5]). The default value is + `SHIFT-JIS`. + core.symlinks:: If false, symbolic links are checked out as small plain files that contain the link text. linkgit:git-update-index[1] and diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index a8dbf4be30..ea5a9509c6 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -283,10 +283,10 @@ visualize the content. In these cases you can tell Git the encoding of a file in the working directory with the `working-tree-encoding` attribute. If a file with this -attributes is added to Git, then Git reencodes the content from the -specified encoding to UTF-8 and stores the result in its internal data -structure (called "the index"). On checkout the content is encoded -back to the specified encoding. +attribute is added to Git, then Git reencodes the content from the +specified encoding to UTF-8. Finally, Git stores the UTF-8 encoded +content in its internal data structure (called "the index"). On checkout +the content is reencoded back to the specified encoding. Please note that using the `working-tree-encoding` attribute may have a number of pitfalls: @@ -296,32 +296,38 @@ number of pitfalls: expected encoding. Consequently, these files will appear different which typically causes trouble. This is in particular the case for older Git versions and alternative Git implementations such as JGit - or libgit2 (as of January 2018). + or libgit2 (as of February 2018). -- Reencoding content to non-UTF encodings (e.g. SHIFT-JIS) can cause - errors as the conversion might not be round trip safe. +- Reencoding content to non-UTF encodings can cause errors as the + conversion might not be UTF-8 round trip safe. If you suspect your + encoding to not be round trip safe, then add it to `core.checkRoundtripEncoding` + to make Git check the round trip encoding (see linkgit:git-config[1]). + SHIFT-JIS (Japanese character set) is known to have round trip issues + with UTF-8 and is checked by default. - Reencoding content requires resources that might slow down certain Git operations (e.g 'git checkout' or 'git add'). -Use the `working-tree-encoding` attribute only if you cannot store a file in -UTF-8 encoding and if you want Git to be able to process the content as -text. +Use the `working-tree-encoding` attribute only if you cannot store a file +in UTF-8 encoding and if you want Git to be able to process the content +as text. -Use the following attributes if your '*.txt' files are UTF-16 encoded -with byte order mark (BOM) and you want Git to perform automatic line -ending conversion based on your platform. +As an example, use the following attributes if your '*.proj' files are +UTF-16 encoded with byte order mark (BOM) and you want Git to perform +automatic line ending conversion based on your platform. ------------------------ -*.txt text working-tree-encoding=UTF-16 +*.proj text working-tree-encoding=UTF-16 ------------------------ -Use the following attributes if your '*.txt' files are UTF-16 little +Use the following attributes if your '*.proj' files are UTF-16 little endian encoded without BOM and you want Git to use Windows line endings -in the working directory. +in the working directory. Please note, it is highly recommended to +explicitly define the line endings with `eol` if the `working-tree-encoding` +attribute is used to avoid ambiguity. ------------------------ -*.txt working-tree-encoding=UTF-16LE text eol=CRLF +*.proj working-tree-encoding=UTF-16LE text eol=CRLF ------------------------ You can get a list of all available encodings on your platform with the @@ -331,6 +337,13 @@ following command: iconv --list ------------------------ +If you do not know the encoding of a file, then you can use the `file` +command to guess the encoding: + +------------------------ +file foo.proj +------------------------ + `ident` ^^^^^^^ diff --git a/config.c b/config.c index 1f003fbb90..d0ada9fcd4 100644 --- a/config.c +++ b/config.c @@ -1172,6 +1172,11 @@ static int git_default_core_config(const char *var, const char *value) return 0; } + if (!strcmp(var, "core.checkroundtripencoding")) { + check_roundtrip_encoding = xstrdup(value); + return 0; + } + if (!strcmp(var, "core.notesref")) { notes_ref_name = xstrdup(value); return 0; diff --git a/convert.c b/convert.c index 13fad490ce..71dffc7167 100644 --- a/convert.c +++ b/convert.c @@ -269,7 +269,7 @@ static int will_convert_lf_to_crlf(size_t len, struct text_stat *stats, static void trace_encoding(const char *context, const char *path, const char *encoding, const char *buf, size_t len) { - static struct trace_key coe = TRACE_KEY_INIT(CHECKOUT_ENCODING); + static struct trace_key coe = TRACE_KEY_INIT(WORKING_TREE_ENCODING); struct strbuf trace = STRBUF_INIT; int i; @@ -289,6 +289,39 @@ static void trace_encoding(const char *context, const char *path, strbuf_release(&trace); } +static int check_roundtrip(const char* enc_name) +{ + /* + * check_roundtrip_encoding contains a string of space and/or + * comma separated encodings (eg. "UTF-16, ASCII, CP1125"). + * Search for the given encoding in that string. + */ + const char *found = strcasestr(check_roundtrip_encoding, enc_name); + const char *next = found + strlen(enc_name); + int len = strlen(check_roundtrip_encoding); + return (found && ( + /* + * check that the found encoding is at the + * beginning of check_roundtrip_encoding or + * that it is prefixed with a space or comma + */ + found == check_roundtrip_encoding || ( + found > check_roundtrip_encoding && + (*(found-1) == ' ' || *(found-1) == ',') + ) + ) && ( + /* + * check that the found encoding is at the + * end of check_roundtrip_encoding or + * that it is suffixed with a space or comma + */ + next == check_roundtrip_encoding + len || ( + next < check_roundtrip_encoding + len && + (*next == ' ' || *next == ',') + ) + )); +} + static struct encoding { const char *name; struct encoding *next; @@ -333,7 +366,7 @@ static int encode_to_git(const char *path, const char *src, size_t src_len, error(error_msg, path, enc->name); - } else if (has_missing_utf_bom(enc->name, src, src_len)) { + } else if (is_missing_required_utf_bom(enc->name, src, src_len)) { const char *error_msg = _( "BOM is required for '%s' if encoded as %s"); const char *advise_msg = _( @@ -367,22 +400,25 @@ static int encode_to_git(const char *path, const char *src, size_t src_len, trace_encoding("destination", path, default_encoding, dst, dst_len); /* - * UTF supports lossless round tripping [1]. UTF to other encoding are - * mostly round trip safe as Unicode aims to be a superset of all other - * character encodings. However, the SHIFT-JIS (Japanese character set) - * is an exception as some codes are not round trip safe [2]. + * UTF supports lossless conversion round tripping [1] and conversions + * between UTF and other encodings are mostly round trip safe as + * Unicode aims to be a superset of all other character encodings. + * However, certain encodings (e.g. SHIFT-JIS) are known to have round + * trip issues [2]. Check the round trip conversion for all encodings + * listed in core.checkRoundTripEncoding. * - * Reverse the transformation of 'dst' and check the result with 'src' - * if content is written to Git. This ensures no information is lost - * during conversion to/from UTF-8. + * The round trip check is only performed if content is written to Git. + * This ensures that no information is lost during conversion to/from + * the internal UTF-8 representation. * * Please note, the code below is not tested because I was not able to - * generate a faulty round trip without iconv error. + * generate a faulty round trip without an iconv error. Iconv errors + * are already caught above. * * [1] http://unicode.org/faq/utf_bom.html#gen2 * [2] https://support.microsoft.com/en-us/help/170559/prb-conversion-problem-between-shift-jis-and-unicode */ - if ((conv_flags & CONV_WRITE_OBJECT) && !strcmp(enc->name, "SHIFT-JIS")) { + if ((conv_flags & CONV_WRITE_OBJECT) && check_roundtrip(enc->name)) { char *re_src; int re_src_len; @@ -390,6 +426,7 @@ static int encode_to_git(const char *path, const char *src, size_t src_len, enc->name, default_encoding, &re_src_len); + trace_printf("Checking roundtrip encoding for %s...\n", enc->name); trace_encoding("reencoded source", path, enc->name, re_src, re_src_len); @@ -397,10 +434,7 @@ static int encode_to_git(const char *path, const char *src, size_t src_len, memcmp(src, re_src, src_len)) { const char* msg = _("encoding '%s' from %s to %s and " "back is not the same"); - if (conv_flags & CONV_WRITE_OBJECT) - die(msg, path, enc->name, default_encoding); - else - error(msg, path, enc->name, default_encoding); + die(msg, path, enc->name, default_encoding); } free(re_src); @@ -1165,8 +1199,12 @@ static struct encoding *git_path_check_encoding(struct attr_check_item *check) if (!strcasecmp(value, default_encoding)) return NULL; - enc = xcalloc(1, sizeof(struct convert_driver)); - enc->name = xstrdup_toupper(value); /* aways use upper case names! */ + enc = xcalloc(1, sizeof(*enc)); + /* + * Ensure encoding names are always upper case (e.g. UTF-8) to + * simplify subsequent string comparisons. + */ + enc->name = xstrdup_toupper(value); *encoding_tail = enc; encoding_tail = &(enc->next); @@ -1228,7 +1266,7 @@ struct conv_attrs { enum crlf_action attr_action; /* What attr says */ enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */ int ident; - struct encoding *checkout_encoding; /* Supported encoding or default encoding if NULL */ + struct encoding *working_tree_encoding; /* Supported encoding or default encoding if NULL */ }; static void convert_attrs(struct conv_attrs *ca, const char *path) @@ -1262,7 +1300,7 @@ static void convert_attrs(struct conv_attrs *ca, const char *path) else if (eol_attr == EOL_CRLF) ca->crlf_action = CRLF_TEXT_CRLF; } - ca->checkout_encoding = git_path_check_encoding(ccheck + 5); + ca->working_tree_encoding = git_path_check_encoding(ccheck + 5); } else { ca->drv = NULL; ca->crlf_action = CRLF_UNDEFINED; @@ -1344,7 +1382,7 @@ int convert_to_git(const struct index_state *istate, len = dst->len; } - ret |= encode_to_git(path, src, len, dst, ca.checkout_encoding, conv_flags); + ret |= encode_to_git(path, src, len, dst, ca.working_tree_encoding, conv_flags); if (ret && dst) { src = dst->buf; len = dst->len; @@ -1373,7 +1411,7 @@ void convert_to_git_filter_fd(const struct index_state *istate, if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN, NULL)) die("%s: clean filter '%s' failed", path, ca.drv->name); - encode_to_git(path, dst->buf, dst->len, dst, ca.checkout_encoding, conv_flags); + encode_to_git(path, dst->buf, dst->len, dst, ca.working_tree_encoding, conv_flags); crlf_to_git(istate, path, dst->buf, dst->len, dst, ca.crlf_action, conv_flags); ident_to_git(path, dst->buf, dst->len, dst, ca.ident); } @@ -1405,7 +1443,7 @@ static int convert_to_working_tree_internal(const char *path, const char *src, } } - ret |= encode_to_worktree(path, src, len, dst, ca.checkout_encoding); + ret |= encode_to_worktree(path, src, len, dst, ca.working_tree_encoding); if (ret) { src = dst->buf; len = dst->len; @@ -1877,7 +1915,7 @@ struct stream_filter *get_stream_filter(const char *path, const unsigned char *s if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean)) return NULL; - if (ca.checkout_encoding) + if (ca.working_tree_encoding) return NULL; if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF) diff --git a/convert.h b/convert.h index 1d9539ed0b..765abfbd60 100644 --- a/convert.h +++ b/convert.h @@ -56,6 +56,7 @@ struct delayed_checkout { }; extern enum eol core_eol; +extern char *check_roundtrip_encoding; extern const char *get_cached_convert_stats_ascii(const struct index_state *istate, const char *path); extern const char *get_wt_convert_stats_ascii(const char *path); diff --git a/environment.c b/environment.c index 10a32c20ac..5bae9131ad 100644 --- a/environment.c +++ b/environment.c @@ -50,6 +50,7 @@ int check_replace_refs = 1; char *git_replace_ref_base; enum eol core_eol = EOL_UNSET; int global_conv_flags_eol = CONV_EOL_RNDTRP_WARN; +char *check_roundtrip_encoding = "SHIFT-JIS"; unsigned whitespace_rule_cfg = WS_DEFAULT_RULE; enum branch_track git_branch_track = BRANCH_TRACK_REMOTE; enum rebase_setup_type autorebase = AUTOREBASE_NEVER; diff --git a/t/t0028-working-tree-encoding.sh b/t/t0028-working-tree-encoding.sh index 0f36d4990a..5dcdd5f899 100755 --- a/t/t0028-working-tree-encoding.sh +++ b/t/t0028-working-tree-encoding.sh @@ -4,7 +4,7 @@ test_description='working-tree-encoding conversion via gitattributes' . ./test-lib.sh -GIT_TRACE_CHECKOUT_ENCODING=1 && export GIT_TRACE_CHECKOUT_ENCODING +GIT_TRACE_WORKING_TREE_ENCODING=1 && export GIT_TRACE_WORKING_TREE_ENCODING test_expect_success 'setup test repo' ' git config core.eol lf && @@ -22,6 +22,8 @@ test_expect_success 'setup test repo' ' test_expect_success 'ensure UTF-8 is stored in Git' ' git cat-file -p :test.utf16 >test.utf16.git && test_cmp_bin test.utf8.raw test.utf16.git && + + # cleanup rm test.utf8.raw test.utf16.git ' @@ -122,6 +124,10 @@ test_expect_success 'eol conversion for UTF-16 encoded files on checkout' ' cat crlf.utf8.raw | iconv -f UTF-8 -t UTF-16 >crlf.utf16.raw && cp crlf.utf16.raw eol.utf16 && + cat >expectIndexLF <<-\EOF && + i/lf w/-text attr/text eol.utf16 + EOF + git add eol.utf16 && git commit -m eol && @@ -130,11 +136,19 @@ test_expect_success 'eol conversion for UTF-16 encoded files on checkout' ' git -c core.eol=crlf checkout eol.utf16 && test_cmp_bin crlf.utf16.raw eol.utf16 && + # Although the file has CRLF in the working tree, ensure LF in the index + git ls-files --eol eol.utf16 >actual && + test_cmp expectIndexLF actual && + # UTF-16 with LF (Unix line endings) rm eol.utf16 && git -c core.eol=lf checkout eol.utf16 && test_cmp_bin lf.utf16.raw eol.utf16 && + # The file LF in the working tree, ensure LF in the index + git ls-files --eol eol.utf16 >actual && + test_cmp expectIndexLF actual&& + rm crlf.utf16.raw crlf.utf8.raw lf.utf16.raw lf.utf8.raw && # cleanup @@ -195,4 +209,45 @@ test_expect_success 'error if encoding garbage is already in Git' ' git reset --hard $BEFORE_STATE ' +test_expect_success 'check roundtrip encoding' ' + text="hallo there!\nroundtrip test here!" && + printf "$text" | iconv -f UTF-8 -t SHIFT-JIS >roundtrip.shift && + printf "$text" | iconv -f UTF-8 -t UTF-16 >roundtrip.utf16 && + echo "*.shift text working-tree-encoding=SHIFT-JIS" >>.gitattributes && + + # SHIFT-JIS encoded files are round-trip checked by default... + GIT_TRACE=1 git add .gitattributes roundtrip.shift 2>&1 >/dev/null | + grep "Checking roundtrip encoding for SHIFT-JIS" && + git reset && + + # ... unless we overwrite the Git config! + test_config core.checkRoundTripEncoding "garbage" && + ! GIT_TRACE=1 git add .gitattributes roundtrip.shift 2>&1 >/dev/null | + grep "Checking roundtrip encoding for SHIFT-JIS" && + test_unconfig core.checkRoundTripEncoding && + git reset && + + # UTF-16 encoded files should not be round-trip checked by default... + ! GIT_TRACE=1 git add roundtrip.utf16 2>&1 >/dev/null | + grep "Checking roundtrip encoding for UTF-16" && + git reset && + + # ... unless we tell Git to check it! + test_config_global core.checkRoundTripEncoding "UTF-16, UTF-32" && + GIT_TRACE=1 git add roundtrip.utf16 2>&1 >/dev/null | + grep "Checking roundtrip encoding for UTF-16" && + git reset && + + # ... unless we tell Git to check it! + # (here we also check that the casing of the encoding is irrelevant) + test_config_global core.checkRoundTripEncoding "UTF-32, utf-16" && + GIT_TRACE=1 git add roundtrip.utf16 2>&1 >/dev/null | + grep "Checking roundtrip encoding for UTF-16" && + git reset && + + # cleanup + rm roundtrip.shift roundtrip.utf16 && + git reset --hard HEAD +' + test_done diff --git a/utf8.c b/utf8.c index f033fec1c2..5113d26e56 100644 --- a/utf8.c +++ b/utf8.c @@ -562,7 +562,7 @@ int has_prohibited_utf_bom(const char *enc, const char *data, size_t len) ); } -int has_missing_utf_bom(const char *enc, const char *data, size_t len) +int is_missing_required_utf_bom(const char *enc, const char *data, size_t len) { return ( !strcmp(enc, "UTF-16") && diff --git a/utf8.h b/utf8.h index 26b5e91852..62f86fba64 100644 --- a/utf8.h +++ b/utf8.h @@ -93,6 +93,6 @@ int has_prohibited_utf_bom(const char *enc, const char *data, size_t len); * Section 3.10, D98, page 132 * [3] https://encoding.spec.whatwg.org/#utf-16le */ -int has_missing_utf_bom(const char *enc, const char *data, size_t len); +int is_missing_required_utf_bom(const char *enc, const char *data, size_t len); #endif ### Patches Lars Schneider (7): strbuf: remove unnecessary NUL assignment in xstrdup_tolower() strbuf: add xstrdup_toupper() utf8: add function to detect prohibited UTF-16/32 BOM utf8: add function to detect a missing UTF-16/32 BOM convert: add 'working-tree-encoding' attribute convert: add tracing for 'working-tree-encoding' attribute convert: add round trip check based on 'core.checkRoundtripEncoding' Documentation/config.txt | 6 + Documentation/gitattributes.txt | 73 +++++++++++ config.c | 5 + convert.c | 256 ++++++++++++++++++++++++++++++++++++++- convert.h | 2 + environment.c | 1 + sha1_file.c | 2 +- strbuf.c | 13 +- strbuf.h | 1 + t/t0028-working-tree-encoding.sh | 253 ++++++++++++++++++++++++++++++++++++++ utf8.c | 37 ++++++ utf8.h | 25 ++++ 12 files changed, 671 insertions(+), 3 deletions(-) create mode 100755 t/t0028-working-tree-encoding.sh base-commit: 8a2f0888555ce46ac87452b194dec5cb66fb1417 -- 2.16.1
