Resist against renaming of columns

R/relational-duckdb.R

@@ -70,7 +70,14 @@ duckdb_rel_from_df <- function(df) {
   tryCatch(
     {
       # duckdb:::df_is_materialized() is broken and unneeded
-      return(duckdb:::rel_from_altrep_df(df))
+      rel <- duckdb:::rel_from_altrep_df(df)
+      rel_names <- duckdb:::rapi_rel_names(rel)
+      if (!identical(rel_names, names(df))) {
+        # This can happen when column names change for an existing relational data frame
+        exprs <- nexprs_from_loc(rel_names, set_names(seq_along(df), names(df)))
+        rel <- rel_project.duckdb_relation(rel, exprs)
+      }
+      return(rel)
     },
     error = function(e) {}
   )

tests/testthat/test-relational-duckdb.R

@@ -22,12 +22,25 @@ test_that("duckdb_rel_from_df()", {
 
   expect_silent(duckdb_rel_from_df(df))
 
+  # If this is no longer an eror, we need to make sure that subsetting
+  # forwards to the vector class
   expect_snapshot(error = TRUE, {
     data.frame(a = vctrs::new_vctr(1:3)) %>%
       duckdb_rel_from_df()
   })
 })
 
+test_that("duckdb_rel_from_df() and changing column names", {
+  withr::local_envvar(DUCKPLYR_FORCE = TRUE)
+
+  x <-
+    data.frame(a = 1) %>%
+    duckplyr_select(a)
+
+  names(x) <- "b"
+  expect_equal(x %>% duckplyr_filter(b == 1), data.frame(b = 1))
+})
+
 test_that("rel_aggregate()", {
   expr_species <- relexpr_reference("species")
   expr_aggregate <- relexpr_function(alias = "mean_bill_length_mm", "avg", list(