Replace isFrame with the new API isDataFrame (#6850)

* Replace isFrame with the new API isDataFrame

Since both the NOTE and the new entry point are in current R-devel,
test for both R version and SVN revision to account for revisions that
lack both the NOTE and the new entry point.

Co-Authored-By: Tyson Barrett <[email protected]>

* Add a TODO

---------

Co-authored-by: Tyson Barrett <[email protected]>
Co-authored-by: Michael Chirico <[email protected]>

Author: 3 people

src/data.table.h

@@ -17,6 +17,10 @@
 #if R_VERSION < R_Version(3, 4, 0)
 #  define SET_GROWABLE_BIT(x)  // #3292
 #endif
+// TODO: remove the `R_SVN_VERSION` check when R 4.5.0 is released (circa Apr. 2025)
+#if R_VERSION < R_Version(4, 5, 0) || R_SVN_REVISION < 86702
+#  define isDataFrame(x) isFrame(x) // #6180
+#endif
 #include <Rinternals.h>
 #define SEXPPTR_RO(x) ((const SEXP *)DATAPTR_RO(x))  // to avoid overhead of looped STRING_ELT and VECTOR_ELT
 #include <stdint.h>    // for uint64_t rather than unsigned long long

src/dogroups.c

@@ -283,7 +283,7 @@ SEXP dogroups(SEXP dt, SEXP dtcols, SEXP groups, SEXP grpcols, SEXP jiscols, SEX
       for (int j=0; j<LENGTH(jval); ++j) {
         thiscol = VECTOR_ELT(jval,j);
         if (isNull(thiscol)) continue;
-        if (!isVector(thiscol) || isFrame(thiscol))
+        if (!isVector(thiscol) || isDataFrame(thiscol))
           error(_("Entry %d for group %d in j=list(...) should be atomic vector or list. If you are trying something like j=list(.SD,newcol=mean(colA)) then use := by group instead (much quicker), or cbind or merge afterwards."), j+1, i+1);
         if (isArray(thiscol)) {
           SEXP dims = PROTECT(getAttrib(thiscol, R_DimSymbol));