Delete the mdoc_node.pending pointer and the function calculating

it, make_pending(), which was the most difficult function of the
whole mdoc(7) parser.  After almost five years of maintaining this
hellhole, i just noticed the pointer isn't needed after all.

Blocks are always rewound in the reverse order they were opened;
that even holds for broken blocks.  Consequently, it is sufficient
to just mark broken blogs with the flag MDOC_BROKEN and breaking
blocks with the flag MDOC_ENDED.  When rewinding, instead of iterating
the pending pointers, just iterate from each broken block to its
parents, rewinding all that are MDOC_ENDED and stopping after
processing the first ancestor that it not MDOC_BROKEN.  For ENDBODY
markers, use the mdoc_node.body pointer in place of the former
mdoc_node.pending.

This also fixes an assertion failure found by jsg@ with afl,
test case #467 (Bo Bl It Bd Bc It), where (surprise surprise)
the pending pointer got corrupted.

Improved functionality, minus one function, minus one struct field,
minus 50 lines of code.

1 files changed, 2 insertions, 0 deletions

diff --git a/regress/usr.bin/mandoc/mdoc/Bl/broken.out_lint b/regress/usr.bin/mandoc/mdoc/Bl/broken.out_lint
index b57a007983d..477b7fbc83a 100644
--- a/regress/usr.bin/mandoc/mdoc/Bl/broken.out_lint
+++ b/regress/usr.bin/mandoc/mdoc/Bl/broken.out_lint
@@ -1 +1,3 @@
 mandoc: broken.in:13:2: WARNING: blocks badly nested: Bo breaks Bl
+mandoc: broken.in:23:2: WARNING: blocks badly nested: Bo breaks Bd
+mandoc: broken.in:25:2: ERROR: inserting missing end of block: It breaks Bd