1 files changed, 31 insertions, 36 deletions

diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index 7da6665cb7..17de4284ce 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -1033,10 +1033,7 @@ void ex_diffsplit(exarg_T *eap)
         if (bufref_valid(&old_curbuf)) {
           // Move the cursor position to that of the old window.
           curwin->w_cursor.lnum = diff_get_corresponding_line(
-              old_curbuf.br_buf,
-              old_curwin->w_cursor.lnum,
-              curbuf,
-              curwin->w_cursor.lnum);
+              old_curbuf.br_buf, old_curwin->w_cursor.lnum);
         }
       }
       // Now that lines are folded scroll to show the cursor at the same
@@ -2463,25 +2460,17 @@ int diff_move_to(int dir, long count)
   return OK;
 }
 
-/// Finds the corresponding line in a diff.
-///
-/// @param buf1
-/// @param lnum1
-/// @param buf2
-/// @param lnum3
-///
-/// @return The corresponding line.
-linenr_T diff_get_corresponding_line(buf_T *buf1, linenr_T lnum1, buf_T *buf2,
-                                     linenr_T lnum3)
+/// Return the line number in the current window that is closest to "lnum1" in
+/// "buf1" in diff mode.
+static linenr_T diff_get_corresponding_line_int(buf_T *buf1, linenr_T lnum1)
 {
   int idx1;
   int idx2;
   diff_T *dp;
   int baseline = 0;
-  linenr_T lnum2;
 
   idx1 = diff_buf_idx(buf1);
-  idx2 = diff_buf_idx(buf2);
+  idx2 = diff_buf_idx(curbuf);
 
   if ((idx1 == DB_COUNT)
       || (idx2 == DB_COUNT)
@@ -2501,15 +2490,9 @@ linenr_T diff_get_corresponding_line(buf_T *buf1, linenr_T lnum1, buf_T *buf2,
 
   for (dp = curtab->tp_first_diff; dp != NULL; dp = dp->df_next) {
     if (dp->df_lnum[idx1] > lnum1) {
-      lnum2 = lnum1 - baseline;
-
-      // don't end up past the end of the file
-      if (lnum2 > buf2->b_ml.ml_line_count) {
-        lnum2 = buf2->b_ml.ml_line_count;
-      }
-
-      return lnum2;
-    } else if ((dp->df_lnum[idx1] + dp->df_count[idx1]) > lnum1) {
+      return lnum1 - baseline;
+    }
+    if ((dp->df_lnum[idx1] + dp->df_count[idx1]) > lnum1) {
       // Inside the diffblock
       baseline = lnum1 - dp->df_lnum[idx1];
 
@@ -2518,30 +2501,42 @@ linenr_T diff_get_corresponding_line(buf_T *buf1, linenr_T lnum1, buf_T *buf2,
       }
 
       return dp->df_lnum[idx2] + baseline;
-    } else if ((dp->df_lnum[idx1] == lnum1)
-               && (dp->df_count[idx1] == 0)
-               && (dp->df_lnum[idx2] <= lnum3)
-               && ((dp->df_lnum[idx2] + dp->df_count[idx2]) > lnum3)) {
+    }
+    if ((dp->df_lnum[idx1] == lnum1)
+        && (dp->df_count[idx1] == 0)
+        && (dp->df_lnum[idx2] <= curwin->w_cursor.lnum)
+        && ((dp->df_lnum[idx2] + dp->df_count[idx2])
+            > curwin->w_cursor.lnum)) {
       // Special case: if the cursor is just after a zero-count
       // block (i.e. all filler) and the target cursor is already
       // inside the corresponding block, leave the target cursor
       // unmoved. This makes repeated CTRL-W W operations work
       // as expected.
-      return lnum3;
+      return curwin->w_cursor.lnum;
     }
     baseline = (dp->df_lnum[idx1] + dp->df_count[idx1])
-               - (dp->df_lnum[idx2] + dp->df_count[idx2]);
+                - (dp->df_lnum[idx2] + dp->df_count[idx2]);
   }
 
   // If we get here then the cursor is after the last diff
-  lnum2 = lnum1 - baseline;
+  return lnum1 - baseline;
+}
+
+/// Finds the corresponding line in a diff.
+///
+/// @param buf1
+/// @param lnum1
+///
+/// @return The corresponding line.
+linenr_T diff_get_corresponding_line(buf_T *buf1, linenr_T lnum1)
+{
+  linenr_T lnum = diff_get_corresponding_line_int(buf1, lnum1);
 
   // don't end up past the end of the file
-  if (lnum2 > buf2->b_ml.ml_line_count) {
-    lnum2 = buf2->b_ml.ml_line_count;
+  if (lnum > curbuf->b_ml.ml_line_count) {
+    return curbuf->b_ml.ml_line_count;
   }
-
-  return lnum2;
+  return lnum;
 }
 
 /// For line "lnum" in the current window find the equivalent lnum in window