Fix blocking conditionality

R/accessory.R

@@ -915,7 +915,7 @@ read_contrasts <-
     contrasts <- read_metadata(filename)
     contrast_cols <- c(variable_column, reference_column, target_column)
     if (! blocking_column %in% names(contrasts)){
-        contrasts[[blocking_column]] <- ''
+        contrasts[[blocking_column]] <- NA
     }
 
     # Check contrast headers are as expected
@@ -930,12 +930,12 @@ read_contrasts <-
 
     success <- checkListIsSubset(contrasts$variable, colnames(samples), "contrast variables", "sample metadata")
 
-    if (! blocking_column %in% names(contrasts)){
-        blocking <- unlist(lapply(contrasts[[blocking_column]], function(x) simpleSplit(x, ";")))
-        blocking <- blocking[!is.na(blocking)]
-        if (length(blocking > 0)) {
-          success <- checkListIsSubset(blocking, colnames(samples), "blocking variables", "sample metadata")
-        }
+    # Check blocking variables, where supplied
+
+    blocking <- unlist(lapply(contrasts[[blocking_column]], function(x) simpleSplit(x, ";")))
+    blocking <- blocking[!is.na(blocking)]
+    if (length(blocking > 0)) {
+      success <- checkListIsSubset(blocking, colnames(samples), "blocking variables", "sample metadata")
     }
 
     ## 'reference', 'target', and 'blocking' should be values of their variable