[groff] 04/04: [tbl]: Compensate harder (Savannah #62471).

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit db07433b17c2874d70c011808be8823e7323f068
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sun Jan 14 10:00:10 2024 -0600

    [tbl]: Compensate harder (Savannah #62471).
    
    [tbl]: Re-fix Savannah #62471 (vrules in nroff and no-space modes).
    
    * src/preproc/tbl/table.cpp (do_top): Compensate harder for
      non-intersected vertical rules occurring at the top of a table in
      nroff mode.  The previous strategy would fail if no-space mode was on
      and the drawing position was at the top of a page, provoking an error
      from grotty ("output above first line discarded").  Restore spacing
      before issuing `sp` request.
    
    Continues fixing Savannah #62471, and commit 6ccdab9d64, 29 December.
---
 ChangeLog                 | 15 +++++++++++++++
 src/preproc/tbl/table.cpp |  7 +++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 768cd8ca8..33cb92375 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2024-01-14  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [tbl]: Re-fix Savannah #62471 (vrules in nroff and no-space
+       modes).
+
+       * src/preproc/tbl/table.cpp (do_top): Compensate harder for
+       non-intersected vertical rules occurring at the top of a table
+       in nroff mode.  The previous strategy would fail if no-space
+       mode was on and the drawing position was at the top of a page,
+       provoking an error from grotty ("output above first line
+       discarded").  Restore spacing before issuing `sp` request.
+
+       Continues fixing Savannah #62471, and commit 6ccdab9d64, 29
+       December.
+
 2024-01-14  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [tbl]: Add another test case.
diff --git a/src/preproc/tbl/table.cpp b/src/preproc/tbl/table.cpp
index 93ab4b9ff..c3e65d429 100644
--- a/src/preproc/tbl/table.cpp
+++ b/src/preproc/tbl/table.cpp
@@ -3066,8 +3066,11 @@ void table::do_top()
   // horizontal rule on the first row.  This is necessary for grotty's
   // rule intersection detection.  We must make room for it so that the
   // vertical rule is not drawn above the top of the page.
-  else if ((flags & HAS_TOP_VRULE) && !(flags & HAS_TOP_HRULE))
-    prints(".if n .sp\n");
+  else if ((flags & HAS_TOP_VRULE) && !(flags & HAS_TOP_HRULE)) {
+    prints(".if n \\{\\\n");
+    prints(".  \\\" Compensate for vertical rule at top of table.\n");
+    prints(".  rs\n.  sp\n.\\}\n");
+  }
   prints(".nr " STARTING_PAGE_REG " \\n%\n");
   //printfs(".mk %1\n", row_top_reg(0));
 }