gnu: rxvt-unicode: Fix the cursor position when opening new windows in 9.31.

Fixes <https://issues.guix.gnu.org/64719>.

* gnu/packages/patches/rxvt-unicode-fix-cursor-position.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/xdisorg.scm (rxvt-unicode)[source]: Use it.

3 files changed, 81 insertions, 0 deletions

diff --git a/gnu/local.mk b/gnu/local.mk
index f0a59f1658..1a246c1c52 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1926,6 +1926,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/rust-webbrowser-remove-unsupported-os.patch	\
   %D%/packages/patches/rust-wl-clipboard-rs-newer-wl.patch      \
   %D%/packages/patches/rw-igraph-0.10.patch			\
+  %D%/packages/patches/rxvt-unicode-fix-cursor-position.patch	\
   %D%/packages/patches/sbc-fix-build-non-x86.patch		\
   %D%/packages/patches/sbcl-aserve-add-HTML-5-elements.patch	\
   %D%/packages/patches/sbcl-aserve-fix-rfe12668.patch	\
diff --git a/gnu/packages/patches/rxvt-unicode-fix-cursor-position.patch b/gnu/packages/patches/rxvt-unicode-fix-cursor-position.patch
new file mode 100644
index 0000000000..1905c4ccf6
--- /dev/null
+++ b/gnu/packages/patches/rxvt-unicode-fix-cursor-position.patch
@@ -0,0 +1,79 @@
+Fix a bug that causes the cursor position to be incorrect when opening
+new terminals:
+
+http://lists.schmorp.de/pipermail/rxvt-unicode/2023q1/002639.html
+https://bugs.archlinux.org/task/77062
+https://gitlab.alpinelinux.org/alpine/aports/-/issues/14525
+
+This patches reverts all changes made to 'src/screen.C' in rxvt-unicode 9.31.
+
+--- rxvt-unicode-9.31/src/screen.C	2022-08-08 06:33:08.000000000 -0400
++++ rxvt-unicode-9.30/src/screen.C	2021-07-02 23:55:47.000000000 -0400
+@@ -293,7 +293,6 @@
+ 
+       int common_col = min (prev_ncol, ncol);
+ 
+-      // resize swap_buf, blank drawn_buf
+       for (int row = min (nrow, prev_nrow); row--; )
+         {
+           scr_blank_screen_mem (drawn_buf [row], DEFAULT_RSTYLE);
+@@ -307,7 +306,6 @@
+       int pend = MOD (term_start + top_row  , prev_total_rows);
+       int q    = total_rows; // rewrapped row
+ 
+-#if ENABLE_FRILLS
+       if ((rewrap_always || top_row) && !rewrap_never)
+         {
+           // Re-wrap lines. This is rather ugly, possibly because I am too dumb
+@@ -389,35 +387,36 @@
+               scr_blank_line (*qline, qline->l, ncol - qline->l, DEFAULT_RSTYLE);
+             }
+           while (p != pend && q > 0);
++
++          term_start = total_rows - nrow;
++          top_row = q - term_start;
++
++          // make sure all terminal lines exist
++          while (top_row > 0)
++            scr_blank_screen_mem (ROW (--top_row), DEFAULT_RSTYLE);
+         }
+       else
+-#endif
+         {
+-          // wing, instead of wrap
+-          screen.cur.row += nrow - prev_nrow;
++          // if no scrollback exists (yet), wing, instead of wrap
+ 
+-          do
++          for (int row = min (nrow, prev_nrow); row--; )
+             {
+-              p = MOD (p - 1, prev_total_rows);
+-              q--;
++              line_t &src = prev_row_buf [MOD (term_start + row, prev_total_rows)];
++              line_t &dst = row_buf [row];
+ 
+-              copy_line (row_buf [q], prev_row_buf [p]);
++              copy_line (dst, src);
+             }
+-          while (p != pend && q > 0);
+-        }
+ 
+-      term_start = total_rows - nrow;
+-      top_row = q - term_start;
++          for (int row = prev_nrow; row < nrow; row++)
++            scr_blank_screen_mem (row_buf [row], DEFAULT_RSTYLE);
+ 
+-      // make sure all terminal lines exist
+-      while (top_row > 0)
+-        scr_blank_screen_mem (ROW (--top_row), DEFAULT_RSTYLE);
++          term_start = 0;
++        }
+ 
+       clamp_it (screen.cur.row, 0, nrow - 1);
+       clamp_it (screen.cur.col, 0, ncol - 1);
+     }
+ 
+-  // ensure drawn_buf, swap_buf and terminal rows are all initialized
+   for (int row = nrow; row--; )
+     {
+       if (!ROW       (row).valid ()) scr_blank_screen_mem (ROW       (row), DEFAULT_RSTYLE);
diff --git a/gnu/packages/xdisorg.scm b/gnu/packages/xdisorg.scm
index 1c1ca32e7e..ee6e00f518 100644
--- a/gnu/packages/xdisorg.scm
+++ b/gnu/packages/xdisorg.scm
@@ -1335,6 +1335,7 @@ compact configuration syntax.")
               (method url-fetch)
               (uri (string-append "http://dist.schmorp.de/rxvt-unicode/Attic/"
                                   name "-" version ".tar.bz2"))
+              (patches (search-patches "rxvt-unicode-fix-cursor-position.patch"))
               (sha256
                (base32
                 "1s3jcvac40zzp03fvmhjsdpsjx0gb1wk54qz74zhzzj9q75kz8da"))))