Fail safe when a column is missing

bokeh · mattpap · Jul 9, 2020 · Jun 14, 2020 · Jun 26, 2020 · Jun 26, 2020
commit b20dfb73f6cbf63c426ebc948762c2378bc15c79
diff --git a/bokehjs/src/lib/core/properties.ts b/bokehjs/src/lib/core/properties.ts
@@ -1,4 +1,5 @@
 import {Signal0} from "./signaling"
+import {logger} from "./logging"
 import type {HasProps} from "./has_props"
 import * as enums from "./enums"
 import {Arrayable, NumberArray, ColorArray} from "./types"
@@ -368,25 +369,28 @@ export abstract class VectorSpec<T, V extends Vector<T> = Vector<T>> extends Pro
   }
 
   array(source: ColumnarDataSource): Arrayable<unknown> {
-    let ret: any
+    let array: Arrayable
+
+    const length = source.get_length() ?? 1
 
     if (this.spec.field != null) {
-      ret = this.normalize(source.get_column(this.spec.field))
-      if (ret == null)
-        throw new Error(`attempted to retrieve property array for nonexistent field '${this.spec.field}'`)
+      const column = source.get_column(this.spec.field)
+      if (column != null)
+        array = this.normalize(column)
+      else {
+        logger.warn(`attempted to retrieve property array for nonexistent field '${this.spec.field}'`)
+        array = repeat(NaN, length)
+      }
     } else if (this.spec.expr != null) {
-      ret = this.normalize(this.spec.expr.v_compute(source))
+      array = this.normalize(this.spec.expr.v_compute(source))
     } else {
-      let length = source.get_length()
-      if (length == null)
-        length = 1
       const value = this.value(false) // don't apply any spec transform
-      ret = repeat(value, length)
+      array = repeat(value, length)
     }
 
     if (this.spec.transform != null)
-      ret = this.spec.transform.v_compute(ret)
-    return ret
+      array = this.spec.transform.v_compute(array)
+    return array
   }
 }
 

diff --git a/bokehjs/test/unit/core/properties.ts b/bokehjs/test/unit/core/properties.ts
@@ -279,13 +279,11 @@ describe("properties module", () => {
       })
 
       it("should throw an Error otherwise", () => {
-        function fn(): void {
-          const source = new ColumnDataSource({data: {}
600F
})
-          const obj = new Some({number_spec: {field: "foo"}})
-          const prop = obj.properties.number_spec
-          prop.array(source)
-        }
-        expect(fn).to.throw(Error, /attempted to retrieve property array for nonexistent field 'foo'/)
+        const source = new ColumnDataSource({data: {bar: [1, 2, 3]}})
+        const obj = new Some({number_spec: {field: "foo"}})
+        const prop = obj.properties.number_spec
+        const arr = prop.array(source)
+        expect(arr).to.be.equal(new Float64Array([NaN, NaN, NaN]))
       })
 
       it("should apply a spec transform to a field", () => {