Fix dbReadTable() returning 0 rows for BigQuery views (#633)

.github/workflows/test-coverage.yaml

@@ -44,7 +44,7 @@ jobs:
 
       - name: Upload test results
         if: failure()
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: coverage-test-failures
           path: ${{ runner.temp }}/package

R/bq-download.R

@@ -136,11 +136,28 @@ bq_table_download <-
       ))
     }
 
-    params <- set_row_params(
-      nrow = bq_table_nrow(x),
-      n_max = n_max,
-      start_index = start_index
+    # For views, bq_table_nrow() returns 0 even when the view has data
+    # because BigQuery doesn't populate numRows for views. We need to 
+    # handle views differently.
+    is_view <- tryCatch(
+      bq_table_meta(x, "type")$type == "VIEW",
+      error = function(e) FALSE
     )
+
+    if (is_view) {
+      # For views, we can't rely on numRows, so we use the user-specified n_max
+      # and let the download process handle pagination naturally
+      params <- list(
+        n_max = if (is.infinite(n_max)) 1e9 else n_max,  # Use large number for Inf
+        start_index = start_index
+      )
+    } else {
+      params <- set_row_params(
+        nrow = bq_table_nrow(x),
+        n_max = n_max,
+        start_index = start_index
+      )
+    }
     n_max <- params$n_max
     start_index <- params$start_index
 

tests/testthat/test-dbi-connection.R

@@ -227,3 +227,31 @@ test_that("DBI::sqlData return TRUE, FALSE for logical class", {
     DBI::SQL(c("TRUE", "FALSE", "NULL"))
   )
 })
+
+test_that("dbReadTable works with views (issue #633)", {
+  skip_if_no_auth()
+
+  tb <- bq_test_table()
+  con <- DBI::dbConnect(bq_dataset(tb$project, tb$dataset))
+
+  # Create a test table with some data
+  test_data <- data.frame(x = 1:3, y = c("a", "b", "c"))
+  DBI::dbWriteTable(con, tb$table, test_data)
+
+  # Create a view based on the table
+  view_name <- paste0(tb$table, "_view")
+  view_sql <- sprintf("CREATE VIEW %s AS SELECT * FROM %s", view_name, tb$table)
+  DBI::dbExecute(con, view_sql)
+  defer(DBI::dbExecute(con, sprintf("DROP VIEW %s", view_name)))
+
+  # Test that dbReadTable works with the view (this was returning 0 rows before the fix)
+  result_view <- DBI::dbReadTable(con, view_name)
+  expect_equal(nrow(result_view), 3)
+  expect_equal(ncol(result_view), 2)
+  expect_equal(result_view$x, c(1, 2, 3))
+
+  # Verify the table still works normally
+  result_table <- DBI::dbReadTable(con, tb$table)
+  expect_equal(nrow(result_table), 3)
+  expect_equal(result_table$x, c(1, 2, 3))
+})