[Nano-devel] [PATCH V2] cutting: when ^K does not actually cut anything, do not add an undo item

[Benno Schulenberg]

V2:
        * DO set modified state when something was actually cut.
        * Only when the mark is off should a final empty line not be cut.
        * Cover also the zap function.

This addresses https://savannah.gnu.org/bugs/?55330.
---
 src/cut.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/cut.c b/src/cut.c
index 0341c598..4124f7fd 100644
--- a/src/cut.c
+++ b/src/cut.c
@@ -109,7 +109,6 @@ void do_cut_text(bool copy_text, bool marked, bool 
cut_till_eof, bool append)
        bool right_side_up = TRUE;
                /* There *is* no region, *or* it is marked forward. */
 #endif
-       size_t was_totsize = openfile->totsize;
 
        /* If cuts were not continuous, or when cutting a region, clear the 
slate. */
        if (!append && (!keep_cutbuffer || marked || cut_till_eof)) {
@@ -168,16 +167,36 @@ void do_cut_text(bool copy_text, bool marked, bool 
cut_till_eof, bool append)
                        UNSET(NO_NEWLINES);
        } else
 #endif /* !NANO_TINY */
-       /* Only set the modification flag if actually something was cut. */
-       if (openfile->totsize != was_totsize)
-               set_modified();
 
+       set_modified();
        refresh_needed = TRUE;
 }
 
+/* Return TRUE when a cut command would not actually cut anything: when
+ * on an empty line at EOF, or when the mark covers zero characters. */
+bool nothing_needs_cutting(void)
+{
+       if ((openfile->current->next == NULL && openfile->current->data[0] == 
'\0'
+#ifndef NANO_TINY
+                                       && openfile->mark == NULL) ||
+                                       (openfile->mark == openfile->current &&
+                                       openfile->mark_x == openfile->current_x
+#endif
+                                       )) {
+#ifndef NANO_TINY
+               openfile->mark = NULL;
+#endif
+               return TRUE;
+       } else
+               return FALSE;
+}
+
 /* Move text from the current buffer into the cutbuffer. */
 void do_cut_text_void(void)
 {
+       if (nothing_needs_cutting())
+               return;
+
 #ifndef NANO_TINY
        /* Only add a new undo item when the current item is not a CUT or when
         * the current cut is not contiguous with the previous cutting. */
@@ -239,6 +258,9 @@ void zap_text(void)
        filestruct *was_cutbuffer = cutbuffer;
        filestruct *was_cutbottom = cutbottom;
 
+       if (nothing_needs_cutting())
+               return;
+
        /* Add a new undo item only when the current item is not a ZAP or when
         * the current zap is not contiguous with the previous zapping. */
        if (openfile->last_action != ZAP || openfile->current_undo == NULL ||
-- 
2.19.2