pretty.c: format string with truncate respects logOutputEncoding

Pretty format string %<(N,[ml]trunc)>%s truncates subject to a given
length with an appropriate padding. This works for non-ASCII texts when
i18n.logOutputEncoding is UTF-8 only (independently of a printed commit
message encoding) but does not work when i18n.logOutputEncoding is NOT
UTF-8.

In 7e77df3 (pretty: two phase conversion for non utf-8 commits, 2013-04-19)
'format_commit_item' function assumes commit message to be in UTF-8.
And that was so until ecaee80 (pretty: --format output should honor
logOutputEncoding, 2013-06-26) where conversion to logOutputEncoding was
added before calling 'format_commit_message'.

Correct this by converting a commit message to UTF-8 first (as it
assumed in 7e77df3 (pretty: two phase conversion for non utf-8 commits,
2013-04-19)). Only after that convert a commit message to an actual
logOutputEncoding.

Signed-off-by: Alexey Shumkin <Alex.Crezoff@gmail.com>
Reviewed-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pretty.c

@@ -1506,13 +1506,18 @@ void format_commit_message(const struct commit *commit,
 	context.commit = commit;
 	context.pretty_ctx = pretty_ctx;
 	context.wrap_start = sb->len;
+	/*
+	 * convert a commit message to UTF-8 first
+	 * as far as 'format_commit_item' assumes it in UTF-8
+	 */
 	context.message = logmsg_reencode(commit,
 					  &context.commit_encoding,
-					  output_enc);
+					  utf8);
 
 	strbuf_expand(sb, format, format_commit_item, &context);
 	rewrap_message_tail(sb, &context, 0, 0, 0);
 
+	/* then convert a commit message to an actual output encoding */
 	if (output_enc) {
 		if (same_encoding(utf8, output_enc))
 			output_enc = NULL;

t/t4205-log-pretty-formats.sh

@@ -220,7 +220,7 @@ EOF
 	test_cmp expected actual
 '
 
-test_expect_failure 'left alignment formatting with trunc. i18n.logOutputEncoding' '
+test_expect_success 'left alignment formatting with trunc. i18n.logOutputEncoding' '
 	git -c i18n.logOutputEncoding=$test_encoding log --pretty="tformat:%<(10,trunc)%s" >actual &&
 	qz_to_tab_space <<EOF | iconv -f utf-8 -t $test_encoding >expected &&
 message ..
@@ -242,7 +242,7 @@ EOF
 	test_cmp expected actual
 '
 
-test_expect_failure 'left alignment formatting with ltrunc. i18n.logOutputEncoding' '
+test_expect_success 'left alignment formatting with ltrunc. i18n.logOutputEncoding' '
 	git -c i18n.logOutputEncoding=$test_encoding log --pretty="tformat:%<(10,ltrunc)%s" >actual &&
 	qz_to_tab_space <<EOF | iconv -f utf-8 -t $test_encoding >expected &&
 ..sage two
@@ -264,7 +264,7 @@ EOF
 	test_cmp expected actual
 '
 
-test_expect_failure 'left alignment formatting with mtrunc. i18n.logOutputEncoding' '
+test_expect_success 'left alignment formatting with mtrunc. i18n.logOutputEncoding' '
 	git -c i18n.logOutputEncoding=$test_encoding log --pretty="tformat:%<(10,mtrunc)%s" >actual &&
 	qz_to_tab_space <<EOF | iconv -f utf-8 -t $test_encoding >expected &&
 mess.. two
@@ -420,7 +420,7 @@ initial...   A U Thor
 EOF
 	test_cmp expected actual
 '
-test_expect_failure 'left/right alignment formatting with stealing. i18n.logOutputEncoding' '
+test_expect_success 'left/right alignment formatting with stealing. i18n.logOutputEncoding' '
 	git -c i18n.logOutputEncoding=$test_encoding log --pretty="tformat:%<(10,trunc)%s%>>(10,ltrunc)% an" >actual &&
 	cat <<EOF | iconv -f utf-8 -t $test_encoding >expected &&
 short long  long long

t/t6006-rev-list-format.sh

@@ -256,7 +256,7 @@ commit $head1
 $added_iso88591
 EOF
 
-test_format complex-subject-trunc "%<($truncate_count,trunc)%s" failure <<EOF
+test_format complex-subject-trunc "%<($truncate_count,trunc)%s" <<EOF
 commit $head3
 Test printing of c..
 commit $head2
@@ -265,7 +265,7 @@ commit $head1
 added (hinzugef${added_utf8_part_iso88591}gt..
 EOF
 
-test_format complex-subject-mtrunc "%<($truncate_count,mtrunc)%s" failure <<EOF
+test_format complex-subject-mtrunc "%<($truncate_count,mtrunc)%s" <<EOF
 commit $head3
 Test prin..ex bodies
 commit $head2
@@ -274,7 +274,7 @@ commit $head1
 added (hi..f${added_utf8_part_iso88591}gt) foo
 EOF
 
-test_format complex-subject-ltrunc "%<($truncate_count,ltrunc)%s" failure <<EOF
+test_format complex-subject-ltrunc "%<($truncate_count,ltrunc)%s" <<EOF
 commit $head3
 .. of complex bodies
 commit $head2