Embellished list column error and added news item (#3429)

Rdatatable · Feb 26, 2019 · c613ff9 · c613ff9
1 parent 36c57d8
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Showing 3 changed files with 8 additions and 2 deletions.
diff --git a/NEWS.md b/NEWS.md
@@ -50,6 +50,11 @@
 
 10. `foverlaps` provides better error messages when one interval is POSIXct and other isn't. Also, it warns when POSIXct interval columns are not all of same timezone. Closes [#1143](https://github.com/Rdatatable/data.table/issues/1143). Thanks to @DavidArenburg for the report.
 
+11. From v1.12.0, `unique(DT)` checks up-front the types of all the columns and will fail if any column is type `list`. Use `unique(DT, by=...)` to specify columns that are not type `list`. v1.11.8 and before would also correctly fail with the same error, but not when uniqueness had been established in prior columns (it would stop early and not look at the `list` column). Checking up-front was necessary for some internal optimizations and it's probably best to be explicit anyway. Thanks to James Lamb for reporting, [#3332](https://github.com/Rdatatable/data.table/issues/3332). The error message has been embellished :
+    ```
+    Column 2 of by= (2) is type 'list', not yet supported. Please use the by= argument to specify columns with types that are supported.
+    ```
+
 
 ### Changes in v1.12.0  (13 Jan 2019)
 

diff --git a/inst/tests/tests.Rraw b/inst/tests/tests.Rraw
@@ -4359,7 +4359,7 @@ test(1251.9, DT[base::order(x, list(-y), decreasing=TRUE)],
 # more "edge cases" to ensure we're consistent with base
 test(1251.11, DT[order("a")], DT[1L])
 test(1251.12, DT[order("b", "a")], DT[1L])
-test(1251.13, DT[order(list("b", "a"))], error = "Column 1 of by= (1) is type 'list', not yet supported")
+test(1251.13, DT[order(list("b", "a"))], error = "Column 1 of by= [(]1[)] is type 'list', not yet supported. Please use the by=.*that are supported")
 test(1251.14, DT[order(list("b"), list("a"))], DT[1L])
 
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diff --git a/src/forder.c b/src/forder.c
@@ -504,7 +504,8 @@ SEXP forder(SEXP DT, SEXP by, SEXP retGrpArg, SEXP sortGroupsArg, SEXP ascArg, S
       range_str(STRING_PTR(x), nrow, &min, &max, &na_count);
       break;
     default:
-       Error("Column %d of by= (%d) is type '%s', not yet supported", col+1, INTEGER(by)[col], type2char(TYPEOF(x)));
+      Error("Column %d of by= (%d) is type '%s', not yet supported. Please use the by= argument to specify columns with types that are supported. See NEWS item in v1.12.2 for more information.",
+            col+1, INTEGER(by)[col], type2char(TYPEOF(x)));
     }
     TEND(3);
     if (na_count==nrow || (min>0 && min==max && na_count==0 && infnan_count==0)) {