| Message ID | 20191031092618.29073-4-congdanhqx@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Linux with musl libc improvement | expand |
Hi, On Thu, 31 Oct 2019, Doan Tran Cong Danh wrote: > On musl libc, ISO-2022-JP encoder is too eager to switch back to > 1 byte encoding, musl's iconv always switch back after every combining > character. Comparing glibc and musl's output for this command > $ sed q t/t3900/ISO-2022-JP.txt| iconv -f ISO-2022-JP -t utf-8 | > iconv -f utf-8 -t ISO-2022-JP | xxd > > glibc: > 00000000: 1b24 4224 4f24 6c24 5224 5b24 551b 2842 .$B$O$l$R$[$U.(B > 00000010: 0a . > > musl: > 00000000: 1b24 4224 4f1b 2842 1b24 4224 6c1b 2842 .$B$O.(B.$B$l.(B > 00000010: 1b24 4224 521b 2842 1b24 4224 5b1b 2842 .$B$R.(B.$B$[.(B > 00000020: 1b24 4224 551b 2842 0a .$B$U.(B. > > Although musl iconv's output isn't optimal, it's still correct. > > From commit 7d509878b8, ("pretty.c: format string with truncate respects > logOutputEncoding", 2014-05-21), we're encoding the message to utf-8 > first, then format it and convert the message to the actual output > encoding on git commit --squash. > > Thus, t3900 is failing on Linux with musl libc. > > Reencode to utf-8 before arranging rebase's todo list. Since the re-encoded commit messages are only used for figuring out the relationships between the `fixup!`/`squash!` commits and their targets, but are not used in any of the lines that are written out, this change looks good to me. In fact, all three patches look good to me. Thanks for unbreaking Git with musl! Johannes > > Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com> > --- > > Notes: > The todo list shown to user has already been reencoded by sequencer_make_script, > without this patch it looks like this: > > $ head -3 .git/rebase-merge/git-rebase-todo | xxd > 00000000: 7069 636b 2065 6633 3961 3033 201b 2442 pick ef39a03 .$B > 00000010: 244f 1b28 421b 2442 246c 1b28 421b 2442 $O.(B.$B$l.(B.$B > 00000020: 2452 1b28 421b 2442 245b 1b28 421b 2442 $R.(B.$B$[.(B.$B > 00000030: 2455 1b28 420a 7069 636b 2062 3832 3931 $U.(B.pick b8291 > 00000040: 3336 2073 7175 6173 6821 201b 2442 244f 36 squash! .$B$O > 00000050: 1b28 421b 2442 246c 1b28 421b 2442 2452 .(B.$B$l.(B.$B$R > 00000060: 1b28 421b 2442 245b 1b28 421b 2442 2455 .(B.$B$[.(B.$B$U > 00000070: 1b28 420a 7069 636b 2062 3532 3132 6437 .(B.pick b5212d7 > 00000080: 2069 6e74 6572 6d65 6469 6174 6520 636f intermediate co > 00000090: 6d6d 6974 0a mmit. > > sequencer.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/sequencer.c b/sequencer.c > index 9d5964fd81..69430fe23f 100644 > --- a/sequencer.c > +++ b/sequencer.c > @@ -5169,7 +5169,7 @@ int todo_list_rearrange_squash(struct todo_list *todo_list) > *commit_todo_item_at(&commit_todo, item->commit) = item; > > parse_commit(item->commit); > - commit_buffer = get_commit_buffer(item->commit, NULL); > + commit_buffer = logmsg_reencode(item->commit, NULL, "UTF-8"); > find_commit_subject(commit_buffer, &subject); > format_subject(&buf, subject, " "); > subject = subjects[i] = strbuf_detach(&buf, &subject_len); > -- > 2.24.0.rc1.3.g89530838a3.dirty > >
On Thu, Oct 31, 2019 at 11:38:14AM +0100, Johannes Schindelin wrote: > On Thu, 31 Oct 2019, Doan Tran Cong Danh wrote: > > > On musl libc, ISO-2022-JP encoder is too eager to switch back to > > 1 byte encoding, musl's iconv always switch back after every combining > > character. Comparing glibc and musl's output for this command > > $ sed q t/t3900/ISO-2022-JP.txt| iconv -f ISO-2022-JP -t utf-8 | > > iconv -f utf-8 -t ISO-2022-JP | xxd > > > > glibc: > > 00000000: 1b24 4224 4f24 6c24 5224 5b24 551b 2842 .$B$O$l$R$[$U.(B > > 00000010: 0a . > > > > musl: > > 00000000: 1b24 4224 4f1b 2842 1b24 4224 6c1b 2842 .$B$O.(B.$B$l.(B > > 00000010: 1b24 4224 521b 2842 1b24 4224 5b1b 2842 .$B$R.(B.$B$[.(B > > 00000020: 1b24 4224 551b 2842 0a .$B$U.(B. > > > > Although musl iconv's output isn't optimal, it's still correct. > > > > From commit 7d509878b8, ("pretty.c: format string with truncate respects > > logOutputEncoding", 2014-05-21), we're encoding the message to utf-8 > > first, then format it and convert the message to the actual output > > encoding on git commit --squash. > > > > Thus, t3900 is failing on Linux with musl libc. > > > > Reencode to utf-8 before arranging rebase's todo list. > > Since the re-encoded commit messages are only used for figuring out the > relationships between the `fixup!`/`squash!` commits and their targets, > but are not used in any of the lines that are written out, this change > looks good to me. I'm confused about a few things here, though. I agree with you that the subjects here are only used for finding the fixup/squash relationships. But I don't understand the musl connection. Wouldn't failure to reencode here always be a problem? E.g., if I do: for encoding in utf-8 iso-8859-1; do # commit using the encoding echo $encoding >file && git add file echo "éñcödèd with $encoding" | iconv -f utf-8 -t $encoding | git -c i18n.commitEncoding=$encoding commit -F - # and then fixup without it echo "$encoding fixed" >file && git add file git commit --fixup HEAD done GIT_EDITOR='echo; grep -v ^#' git rebase -i --root --autosquash then the resulting todo-list output (on my glibc system) is: pick 3a5bace éñcödèd with utf-8 fixup aa9f09c fixup! éñcödèd with utf-8 pick 6e85d32 éñcödèd with iso-8859-1 pick 3ceac05 fixup! éñcödèd with iso-8859-1 I.e., we don't actually match up the second pair, and I think we probably ought to. I guess the test in t3900 is less exotic; it uses the same encoding for both commits. And it's just that "foo" and "!fixup foo" can (and do in musl) end up with different encodings (because of the specific language, and the vagaries of each iconv implementation). Would we have similar problems in all of the other functions which use get_commit_buffer() without reencoding? For instance if I do this: echo base >file && git add file && git commit -m base for encoding in utf-8 iso-8859-1; do echo $encoding >file && git add file echo "éñcödèd with $encoding" | iconv -f utf-8 -t $encoding | git -c i18n.commitEncoding=$encoding commit -F - done git checkout -b side HEAD~2 git cherry-pick master master^ cat .git/sequencer/todo then the resulting todo file has a mix of iso-8859-1 and utf-8. It seems to me that we should always be working with the subjects in a single encoding internally, and likewise outputting in that format (which should probably be git_log_output_encoding(), for the instances where we show it to the user). I.e., we should always call logmsg_reencode() instead of get_commit_buffer(). -Peff
On 2019-10-31 15:26:50 -0400, Jeff King wrote: > I'm confused about a few things here, though. I agree with you that the > subjects here are only used for finding the fixup/squash relationships. > But I don't understand the musl connection. You're right. Because of musl's iconv implementation, the problem is being shown up earlier. > Wouldn't failure to reencode here always be a problem? E.g., if I do: > > for encoding in utf-8 iso-8859-1; do > # commit using the encoding > echo $encoding >file && git add file > echo "éñcödèd with $encoding" | iconv -f utf-8 -t $encoding | > git -c i18n.commitEncoding=$encoding commit -F - > # and then fixup without it > echo "$encoding fixed" >file && git add file > git commit --fixup HEAD > done > > GIT_EDITOR='echo; grep -v ^#' git rebase -i --root --autosquash > > then the resulting todo-list output (on my glibc system) is: > > pick 3a5bace éñcödèd with utf-8 > fixup aa9f09c fixup! éñcödèd with utf-8 > pick 6e85d32 éñcödèd with iso-8859-1 > pick 3ceac05 fixup! éñcödèd with iso-8859-1 > > I.e., we don't actually match up the second pair, and I think we > probably ought to. Yes, we ought to match up the second pair, and after changing get_commit_buffer to logmsg_reencode, we do. > > I guess the test in t3900 is less exotic; it uses the same encoding for > both commits. And it's just that "foo" and "!fixup foo" can (and do in > musl) end up with different encodings (because of the specific language, > and the vagaries of each iconv implementation). > > Would we have similar problems in all of the other functions which use > get_commit_buffer() without reencoding? For instance if I do this: > > echo base >file && git add file && git commit -m base > for encoding in utf-8 iso-8859-1; do > echo $encoding >file && git add file > echo "éñcödèd with $encoding" | iconv -f utf-8 -t $encoding | > git -c i18n.commitEncoding=$encoding commit -F - > done > git checkout -b side HEAD~2 > git cherry-pick master master^ > cat .git/sequencer/todo > > then the resulting todo file has a mix of iso-8859-1 and utf-8. > > It seems to me that we should always be working with the subjects in a > single encoding internally, I'm in favour of this idea. > and likewise outputting in that format > (which should probably be git_log_output_encoding(), for the instances > where we show it to the user). This is git's current behaviour but it's get_log_output_encoding() instead of git_log_output_encoding(). > I.e., we should always call logmsg_reencode() instead of > get_commit_buffer().
diff --git a/sequencer.c b/sequencer.c index 9d5964fd81..69430fe23f 100644 --- a/sequencer.c +++ b/sequencer.c @@ -5169,7 +5169,7 @@ int todo_list_rearrange_squash(struct todo_list *todo_list) *commit_todo_item_at(&commit_todo, item->commit) = item; parse_commit(item->commit); - commit_buffer = get_commit_buffer(item->commit, NULL); + commit_buffer = logmsg_reencode(item->commit, NULL, "UTF-8"); find_commit_subject(commit_buffer, &subject); format_subject(&buf, subject, " "); subject = subjects[i] = strbuf_detach(&buf, &subject_len);
On musl libc, ISO-2022-JP encoder is too eager to switch back to 1 byte encoding, musl's iconv always switch back after every combining character. Comparing glibc and musl's output for this command $ sed q t/t3900/ISO-2022-JP.txt| iconv -f ISO-2022-JP -t utf-8 | iconv -f utf-8 -t ISO-2022-JP | xxd glibc: 00000000: 1b24 4224 4f24 6c24 5224 5b24 551b 2842 .$B$O$l$R$[$U.(B 00000010: 0a . musl: 00000000: 1b24 4224 4f1b 2842 1b24 4224 6c1b 2842 .$B$O.(B.$B$l.(B 00000010: 1b24 4224 521b 2842 1b24 4224 5b1b 2842 .$B$R.(B.$B$[.(B 00000020: 1b24 4224 551b 2842 0a .$B$U.(B. Although musl iconv's output isn't optimal, it's still correct. From commit 7d509878b8, ("pretty.c: format string with truncate respects logOutputEncoding", 2014-05-21), we're encoding the message to utf-8 first, then format it and convert the message to the actual output encoding on git commit --squash. Thus, t3900 is failing on Linux with musl libc. Reencode to utf-8 before arranging rebase's todo list. Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com> --- Notes: The todo list shown to user has already been reencoded by sequencer_make_script, without this patch it looks like this: $ head -3 .git/rebase-merge/git-rebase-todo | xxd 00000000: 7069 636b 2065 6633 3961 3033 201b 2442 pick ef39a03 .$B 00000010: 244f 1b28 421b 2442 246c 1b28 421b 2442 $O.(B.$B$l.(B.$B 00000020: 2452 1b28 421b 2442 245b 1b28 421b 2442 $R.(B.$B$[.(B.$B 00000030: 2455 1b28 420a 7069 636b 2062 3832 3931 $U.(B.pick b8291 00000040: 3336 2073 7175 6173 6821 201b 2442 244f 36 squash! .$B$O 00000050: 1b28 421b 2442 246c 1b28 421b 2442 2452 .(B.$B$l.(B.$B$R 00000060: 1b28 421b 2442 245b 1b28 421b 2442 2455 .(B.$B$[.(B.$B$U 00000070: 1b28 420a 7069 636b 2062 3532 3132 6437 .(B.pick b5212d7 00000080: 2069 6e74 6572 6d65 6469 6174 6520 636f intermediate co 00000090: 6d6d 6974 0a mmit. sequencer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)