add test and appropriate changes

Author: Mukulyadav2004

R/bmerge.R

@@ -84,20 +84,17 @@ bmerge = function(i, x, icols, xcols, roll, rollends, nomatch, mult, ops, verbos
           next
         }
       }
-      condition_message <- sprintf(
-        "Incompatible join types: %s (%s) and %s (%s). Factor columns must join to factor or character columns.", # Exact match for tests like 2044.24
-        xname, x_merge_type,
-        iname, i_merge_type
-      )
-      condition <- structure(
+      condition_message = gettextf("Incompatible join types: %s (%s) and %s (%s). Factor columns must join to factor or character columns.", xname, x_merge_type, iname, i_merge_type)
+      condition = structure(
         list(
           message = condition_message,
+          call = sys.call(sys.nframe()-1L),
           bmerge_x_arg_col_name      = names(x)[xcol],
           bmerge_x_arg_type          = x_merge_type,
           bmerge_i_arg_col_name      = names(i)[icol],
           bmerge_i_arg_type          = i_merge_type
         ),
-        class = c("bmerge_incompatible_type_error", "data.table_error", "error", "condition")
+        class = c("dt_bmerge_incompatible_type_error", "error", "condition")
       )
       stop(condition)
     }

R/merge.R

@@ -97,26 +97,16 @@ merge.data.table = function(x, y, by = NULL, by.x = NULL, by.y = NULL, all = FAL
     y = y[yind]
   }
 
-  dt <- tryCatch({
+  dt = tryCatch({
       y[x, nomatch=if (all.x) NA else NULL, on=by, allow.cartesian=allow.cartesian]
     },
-    bmerge_incompatible_type_error = function(e) {
-      # For merge(x=DT1, y=DT2), DT1 (user's 'x') is bmerge's 'i'
-      #                            DT2 (user's 'y') is bmerge's 'x'
-      x_part_col_name <- e$bmerge_i_arg_col_name
-      x_part_type     <- e$bmerge_i_arg_type
-      y_part_col_name <- e$bmerge_x_arg_col_name
-      y_part_type     <- e$bmerge_x_arg_type
+    dt_bmerge_incompatible_type_error = function(e) {
+      x_part_col_name = e$bmerge_i_arg_col_name
+      x_part_type     = e$bmerge_i_arg_type
+      y_part_col_name = e$bmerge_x_arg_col_name
+      y_part_type     = e$bmerge_x_arg_type
 
-      # Use literal "x." and "y." prefixes referring to the arguments of merge()
-      msg <- sprintf(
-        "Incompatible join types: x.%s (%s) and i.%s (%s). Factor columns must join to factor or character columns.",
-        x_part_col_name, x_part_type, 
-        y_part_col_name, y_part_type   
-      )
-      
-      # Remove call = NULL to get "Error in merge.data.table(...): " prefix.
-      stop(errorCondition(message = msg, class = c("datatable_merge_type_error", "data.table_error", "error", "condition")))
+      stopf("Incompatible join types: x.%s (%s) and i.%s (%s). Factor columns must join to factor or character columns.", x_part_col_name, x_part_type, y_part_col_name, y_part_type, class = "dt_merge_incompatible_type_error")
     }
   )
 

inst/tests/tests.Rraw

@@ -21157,3 +21157,8 @@ test(2317.6, DT1[DF1, on='a', .(d = x.a + i.d)]$d, 5)
 test(2317.7, DT1[DF2, on='a', e := i.e]$e, 5)
 test(2317.8, DT1[DF2, on='a', e2 := x.a + i.e]$e2, 6)
 test(2317.9, DT1[DF2, on='a', .(e = x.a + i.e)]$e, 6)
+
+# Test for incompatible factor joins rephrased by merge.data.table(#7048)
+DT1=data.table(a=factor('a'))
+DT2=data.table(a=1L)
+test(2318, merge(DT1, DT2, by = "a"), error = "Incompatible join types: x.a (factor) and i.a (integer). Factor columns must join to factor or character columns.")