Fix two issues causing a class of assertion failures found by jsg@ with afl.

1) rew_sub(): Make sure REWIND_MORE is acted upon even when followed by
REWIND_NONE.  This prevents .It from ending up inside other children of .Bl.
2) blk_exp_close(): Only allow extension of .Bl when it has at least
one .It.  Otherwise, a broken child block could be moved in front of
the .Bl, effectively resulting in a .Bl that ended before it began.

4 files changed, 82 insertions, 5 deletions

diff --git a/regress/usr.bin/mandoc/mdoc/Bl/Makefile b/regress/usr.bin/mandoc/mdoc/Bl/Makefile
index 4e37f578368..299bf820148 100644
--- a/regress/usr.bin/mandoc/mdoc/Bl/Makefile
+++ b/regress/usr.bin/mandoc/mdoc/Bl/Makefile
@@ -1,24 +1,25 @@
-# $OpenBSD: Makefile,v 1.26 2014/11/10 21:54:29 schwarze Exp $
+# $OpenBSD: Makefile,v 1.27 2014/12/20 02:26:42 schwarze Exp $
 
 REGRESS_TARGETS  = item inset diag ohang bullet dash enum hang tag
 REGRESS_TARGETS += column extend nested offset secstart
 
 REGRESS_TARGETS += notype multitype badargs
 REGRESS_TARGETS += empty noIt emptyhead emptytag emptyitem multitag
-REGRESS_TARGETS += bareIt bareTa unclosed break broken
+REGRESS_TARGETS += bareIt bareTa unclosed break breakingIt broken
 
 LINT_TARGETS	 = column notype badargs
 LINT_TARGETS	+= noIt emptyhead emptytag emptyitem
-LINT_TARGETS	+= bareIt bareTa break broken
+LINT_TARGETS	+= bareIt bareTa break breakingIt broken
 
-# groff-1.22.2 defects:
+# groff-1.22.3 defects:
 # - lists with missing or late type ruin indentation
 # - empty lists ruin indentation and sometimes cause empty lines
 # - breaking lists continue indefinitely
+# - breaking items sometimes ruin indentation, sometimes abort processing
 # - breaking a list aborts processing
 # - empty -tag item heads lose the blank line and the indentation
 
-SKIP_GROFF ?= notype empty break broken emptytag
+SKIP_GROFF ?= notype empty break breakingIt broken emptytag
 
 SKIP_TMAN ?= column multitype multitag bareTa break broken
 
diff --git a/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.in b/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.in
new file mode 100644
index 00000000000..bcae378920f
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.in
@@ -0,0 +1,37 @@
+.Dd December 19, 2014
+.Dt BL-BREAKINGIT 1
+.Os OpenBSD
+.Sh NAME
+.Nm Bl-breakingIt
+.Nd items breaking other blocks
+.Sh DESCRIPTION
+.Ss Breaking partial explicit macros
+.Bl -tag -width Ds
+Stray text.
+.Ao
+More stray text.
+.It tag
+Tagged text.
+.El
+.Bl -bullet
+Stray text.
+.Ao
+More stray text.
+.It
+Bullet point.
+.El
+.Ss Breaking full explicit macros
+.Bl -tag -width Ds
+Stray text.
+.Bd -ragged -offset indent
+More stray text.
+.It tag
+Tagged text.
+.El
+.Bl -bullet
+Stray text.
+.Bd -ragged -offset indent
+More stray text.
+.It
+Bullet point.
+.El
diff --git a/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.out_ascii b/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.out_ascii
new file mode 100644
index 00000000000..0013bba8b6b
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.out_ascii
@@ -0,0 +1,27 @@
+BL-BREAKINGIT(1)            General Commands Manual           BL-BREAKINGIT(1)
+
+NNAAMMEE
+     BBll--bbrreeaakkiinnggIItt - items breaking other blocks
+
+DDEESSCCRRIIPPTTIIOONN
+   BBrreeaakkiinngg ppaarrttiiaall eexxpplliicciitt mmaaccrrooss
+     Stray text.  <More stray text.>
+
+     tag     Tagged text.
+     Stray text.  <More stray text.>
+
+     ++oo   Bullet point.
+
+   BBrreeaakkiinngg ffuullll eexxpplliicciitt mmaaccrrooss
+     Stray text.
+
+           More stray text.
+
+     tag     Tagged text.
+     Stray text.
+
+           More stray text.
+
+     ++oo   Bullet point.
+
+OpenBSD                        December 19, 2014                       OpenBSD
diff --git a/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.out_lint b/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.out_lint
new file mode 100644
index 00000000000..50b9dcbf7c8
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Bl/breakingIt.out_lint
@@ -0,0 +1,12 @@
+mandoc: breakingIt.in:13:2: ERROR: inserting missing end of block: It breaks Ao
+mandoc: breakingIt.in:10:1: WARNING: moving content out of list: text
+mandoc: breakingIt.in:11:2: WARNING: moving content out of list: Ao
+mandoc: breakingIt.in:20:2: ERROR: inserting missing end of block: It breaks Ao
+mandoc: breakingIt.in:17:1: WARNING: moving content out of list: text
+mandoc: breakingIt.in:18:2: WARNING: moving content out of list: Ao
+mandoc: breakingIt.in:28:2: ERROR: inserting missing end of block: It breaks Bd
+mandoc: breakingIt.in:25:1: WARNING: moving content out of list: text
+mandoc: breakingIt.in:26:2: WARNING: moving content out of list: Bd
+mandoc: breakingIt.in:35:2: ERROR: inserting missing end of block: It breaks Bd
+mandoc: breakingIt.in:32:1: WARNING: moving content out of list: text
+mandoc: breakingIt.in:33:2: WARNING: moving content out of list: Bd