Don't warn about numeric coercion in set(j=) (#6595)

* Don't warn about numeric coercion in set(j=)

* Fix tests

* very conservative about getAttrib()?

* also demote condition for 'i'

* ????

* undo

---------

Co-authored-by: Benjamin Schwendinger <[email protected]>

Author: MichaelChirico

NEWS.md

@@ -122,6 +122,8 @@
 
 5. A GitHub Actions workflow is now in place to warn the entire maintainer team, as well as any contributor following the GitHub repository, when the package is at risk of archival on CRAN [#7008](https://github.com/Rdatatable/data.table/issues/7008). Thanks @tdhock for the original report and @Bisaloo and @TysonStanley for the fix.
 
+6. Using a double vector in `set()`'s `i=` and/or `j=` no longer throws a warning about preferring integer, [#6594](https://github.com/Rdatatable/data.table/issues/6594). While it may improve efficiency to use integer, there's no guarantee it's an improvement and the difference is likely to be minimal. The coercion will still be reported under `datatable.verbose=TRUE`. For package/production use cases, static analyzers such as `lintr::implicit_integer_linter()` can also report when numeric literals should be rewritten as integer literals.
+
 ## data.table [v1.17.8](https://github.com/Rdatatable/data.table/milestone/41) (6 July 2025)
 
 1. Internal functions used to signal errors are now marked as non-returning, silencing a compiler warning about potentially unchecked allocation failure. Thanks to Prof. Brian D. Ripley for the report and @aitap for the fix, [#7070](https://github.com/Rdatatable/data.table/pull/7070).

inst/tests/tests.Rraw

@@ -1621,9 +1621,9 @@ test(514, x %chin% y, x %in% y)
 
 # Test new function set() in v1.8.0
 DT = data.table(a=1:3,b=4:6)
-test(515, set(DT,2,1,3), data.table(a=c(1L,3L,3L),b=4:6), warning=c("Coerced i from numeric to integer","Coerced j from numeric to integer"))
+test(515, set(DT,2,1,3), data.table(a=c(1L,3L,3L),b=4:6))
 test(516, set(DT,"2",1,3), error="i is type 'character'")
-test(517, set(DT,2L,1,3), DT, warning="Coerced j")
+test(517, options=c(datatable.verbose=TRUE), set(DT,2,1,3), DT, output="Coerced i.*Coerced j")
 # FR #2551 implemented - removed warning from 518
 # test(518, set(DT,2L,1L,3), DT, warning="Coerced 'double' RHS to 'integer'")
 test(518, set(DT,2L,1L,3), DT)

src/assign.c

@@ -219,7 +219,7 @@ SEXP setdt_nrows(SEXP x)
     if (Rf_inherits(xi, "POSIXlt")) {
       error(_("Column %d has class 'POSIXlt'. Please convert it to POSIXct (using as.POSIXct) and run setDT() again. We do not recommend the use of POSIXlt at all because it uses 40 bytes to store one date."), i+1);
     }
-    SEXP dim_xi = getAttrib(xi, R_DimSymbol);
+    SEXP dim_xi = PROTECT(getAttrib(xi, R_DimSymbol));
     R_len_t len_xi, n_dim = length(dim_xi);
     if (n_dim) {
       if (test_matrix_cols && n_dim > 1) {
@@ -230,6 +230,7 @@ SEXP setdt_nrows(SEXP x)
     } else {
       len_xi = length(xi);
     }
+    UNPROTECT(1);
     if (!base_length) {
       base_length = len_xi;
     } else if (len_xi != base_length) {
@@ -364,7 +365,8 @@ SEXP assign(SEXP dt, SEXP rows, SEXP cols, SEXP newcolnames, SEXP values)
   } else {
     if (isReal(rows)) {
       rows = PROTECT(coerceVector(rows, INTSXP)); protecti++;
-      warning(_("Coerced i from numeric to integer. Please pass integer for efficiency; e.g., 2L rather than 2"));
+      if (verbose)
+        Rprintf(_("Coerced %s from numeric to integer. Passing integer directly may be more efficient, e.g., 2L rather than 2"), "i");
     }
     if (!isInteger(rows))
       error(_("i is type '%s'. Must be integer, or numeric is coerced with warning. If i is a logical subset, simply wrap with which(), and take the which() outside the loop if possible for efficiency."), type2char(TYPEOF(rows)));
@@ -417,7 +419,8 @@ SEXP assign(SEXP dt, SEXP rows, SEXP cols, SEXP newcolnames, SEXP values)
   } else {
     if (isReal(cols)) {
       cols = PROTECT(coerceVector(cols, INTSXP)); protecti++;
-      warning(_("Coerced j from numeric to integer. Please pass integer for efficiency; e.g., 2L rather than 2"));
+      if (verbose)
+        Rprintf(_("Coerced %s from numeric to integer. Passing integer directly may be more efficient, e.g., 2L rather than 2"), "j");
     }
     if (!isInteger(cols))
       error(_("j is type '%s'. Must be integer, character, or numeric is coerced with warning."), type2char(TYPEOF(cols)));