coerceAs applied to fill in dcast

NEWS.md

@@ -18,12 +18,14 @@
 
 3. `split.data.table` also accepts a formula for `f`, [#5392](https://github.com/Rdatatable/data.table/issues/5392), mirroring the same in `base::split.data.frame` since R 4.1.0 (May 2021). Thanks to @XiangyunHuang for the request, and @ben-schwen for the PR.
 
-3. Namespace-qualifying `data.table::shift()`, `data.table::first()`, or `data.table::last()` will not deactivate GForce, [#5942](https://github.com/Rdatatable/data.table/issues/5942). Thanks @MichaelChirico for the proposal and fix. Namespace-qualifying other calls like `stats::sum()`, `base::prod()`, etc., continue to work as an escape valve to avoid GForce, e.g. to ensure S3 method dispatch.
+4. Namespace-qualifying `data.table::shift()`, `data.table::first()`, or `data.table::last()` will not deactivate GForce, [#5942](https://github.com/Rdatatable/data.table/issues/5942). Thanks @MichaelChirico for the proposal and fix. Namespace-qualifying other calls like `stats::sum()`, `base::prod()`, etc., continue to work as an escape valve to avoid GForce, e.g. to ensure S3 method dispatch.
 
 ## BUG FIXES
 
 1. `unique()` returns a copy the case when `nrows(x) <= 1` instead of a mutable alias, [#5932](https://github.com/Rdatatable/data.table/pull/5932). This is consistent with existing `unique()` behavior when the input has no duplicates but more than one row. Thanks to @brookslogan for the report and @dshemetov for the fix.
 
+2. `dcast` handles coercion of `fill` to `integer64` correctly, [#4561](https://github.com/Rdatatable/data.table/issues/4561). Thanks to @emallickhossain for the bug report and @MichaelChirico for the fix.
+
 ## NOTES
 
 1. `transform` method for data.table sped up substantially when creating new columns on large tables. Thanks to @OfekShilon for the report and PR. The implemented solution was proposed by @ColeMiller1.

inst/tests/tests.Rraw

@@ -15657,8 +15657,9 @@ test(2071.08, any_na(data.table(c(1+1i, NA))))
 test(2071.09, any_na(data.table(expression(1))), error="Unsupported column type 'expression'")
 test(2071.10, dcast(data.table(a=1, b=1, l=list(list(1))), a ~ b, value.var='l'),
               data.table(a=1, `1`=list(list(1)), key='a'))
-test(2071.11, dcast(data.table(a = 1, b = 2, c = 3), a ~ b, value.var = 'c', fill = '2'),
-              data.table(a=1, `2`=3, key='a'))
+test(2071.11, dcast(data.table(a = c(1, 1, 2), b = c(1, 2, 1), c = 3), a ~ b, value.var='c', fill='4'),
+              data.table(a=c(1, 2), `1`=c(3, 3), `2`=c(3, 4), key='a'),
+              warning="Coercing 'character' RHS to 'double'")
 
 # fifelse, #3657
 test_vec = -5L:5L < 0L
@@ -18304,3 +18305,10 @@ test(2247.2, split(dt, ~y), list(`1`=data.table(x=c(1L,3L), y=1L), `2`=data.tabl
 test(2247.3, do.call(rbind, split(dt, ~y)), setDT(do.call(rbind, split(as.data.frame(dt), ~y))))
 dt = data.table(x=1:4, y=factor(letters[1:2]), z=factor(c(1,1,2,2), labels=c("c", "d")))
 test(2247.4, split(dt, ~y+z), list("a.c"=dt[1], "b.c"=dt[2], "a.d"=dt[3], "b.d"=dt[4]))
+
+# fill converts to int64 in dcast, #4561
+if (test_bit64) {
+  i64v = as.integer64(c(12345678901234, 70, 20, NA))
+  apple = data.table(id = c("a", "b", "b"), time = c(1L, 1L, 2L), y = i64v[1:3])
+  test(2248, dcast(apple, id ~ time, value.var = "y"), data.table(id = c('a', 'b'), `1` = i64v[1:2], `2` = i64v[4:3], key='id'))
+}

src/fcast.c

@@ -16,17 +16,17 @@ SEXP fcast(SEXP lhs, SEXP val, SEXP nrowArg, SEXP ncolArg, SEXP idxArg, SEXP fil
   }
   // get val cols
   for (int i=0; i<nval; ++i) {
-    SEXP thiscol = VECTOR_ELT(val, i);
+    const SEXP thiscol = VECTOR_ELT(val, i);
     SEXP thisfill = fill;
-    SEXPTYPE thistype = TYPEOF(thiscol);
+    const SEXPTYPE thistype = TYPEOF(thiscol);
     int nprotect = 0;
     if (isNull(fill)) {
       if (LOGICAL(is_agg)[0]) {
         thisfill = PROTECT(allocNAVector(thistype, 1)); nprotect++;
       } else thisfill = VECTOR_ELT(fill_d, i);
     }
-    if (TYPEOF(thisfill) != thistype) {
-      thisfill = PROTECT(coerceVector(thisfill, thistype)); nprotect++;
+    if (isVectorAtomic(thiscol)) { // defer error handling to below, but also skip on list
+      thisfill = PROTECT(coerceAs(thisfill, thiscol, /*copyArg=*/ScalarLogical(false))); nprotect++;
     }
     switch (thistype) {
     case INTSXP:
@@ -89,7 +89,7 @@ SEXP fcast(SEXP lhs, SEXP val, SEXP nrowArg, SEXP ncolArg, SEXP idxArg, SEXP fil
         }
       }
       break;
-    default: error(_("Unsupported column type in fcast val: '%s'"), type2char(TYPEOF(thiscol))); // #nocov
+    default: error(_("Unsupported column type in fcast val: '%s'"), type2char(thistype)); // #nocov
     }
     UNPROTECT(nprotect);
   }