all.equal dispatches to column methods

R/setops.R

@@ -262,7 +262,7 @@ all.equal.data.table = function(target, current, trim.levels=TRUE, check.attribu
       # trim.levels moved here
       x = target[[i]]
       y = current[[i]]
-      if (xor(is.factor(x),is.factor(y)))
+      if (XOR(is.factor(x), is.factor(y)))
         stopf("Internal error: factor type mismatch should have been caught earlier") # nocov
       cols.r = TRUE
       if (is.factor(x)) {
@@ -282,8 +282,12 @@ all.equal.data.table = function(target, current, trim.levels=TRUE, check.attribu
           # dealt with according to trim.levels
         }
       } else {
-        cols.r = all.equal(unclass(x), unclass(y), tolerance=tolerance, ..., check.attributes=check.attributes)
-        # classes were explicitly checked earlier above, so ignore classes here.
+        # for test 1710.5 and #4543, we want to (1) make sure we dispatch to
+        #   any existing all.equal methods for x while also (2) treating class(x)/class(y)
+        #   as attributes as regards check.attributes argument
+        cols.r = all.equal(x, y, tolerance=tolerance, ..., check.attributes=check.attributes)
+        if (!isTRUE(cols.r) && !check.attributes && isTRUE(all.equal(unclass(x), unclass(y), tolerance=tolerance, ..., check.attributes=check.attributes)))
+          cols.r = TRUE
       }
       if (!isTRUE(cols.r)) return(paste0("Column '", names(target)[i], "': ", paste(cols.r,collapse=" ")))
     }

R/utils.R

@@ -77,6 +77,9 @@ vapply_1i = function(x, fun, ..., use.names = TRUE) {
   vapply(X = x, FUN = fun, ..., FUN.VALUE = NA_integer_, USE.NAMES = use.names)
 }
 
+# base::xor(), but with scalar operators
+XOR = function(x, y) (x || y) && !(x && y)
+
 # not is.atomic because is.atomic(matrix) is true
 cols_with_dims = function(x) vapply_1i(x, function(j) length(dim(j))) > 0L
 

inst/tests/tests.Rraw

@@ -18709,3 +18709,8 @@ if (test_bit64) local({
   on.exit(library(bit64))
   test(2265, DT, output="abc\\s*1$")
 })
+
+# all.equal failed to dispatch to methods of columns, #4543
+DT1 = data.table(t = .POSIXct(1590973200, tz='UTC'))
+DT2 = data.table(t = .POSIXct(1590974413, tz='UTC'))
+test(2266, all.equal(DT1, DT2), "Column 't': Mean absolute difference: 1213")