Script context should handle arg merging when scripts change

Summary: TSIA

Test Plan: `yarn dev` naviagte to scripts with required args from breadcrumbs.

Reviewers: michelle, philkuz, zasgar

Reviewed By: michelle

Differential Revision: https://phab.corp.pixielabs.ai/D8686

GitOrigin-RevId: c499d94c1d1d6fe2e0dbde19d714c446e84efa0b

src/ui/src/context/new-script-context.tsx

@@ -29,7 +29,7 @@ import { Observable } from 'rxjs';
 import { checkExhaustive } from 'utils/check-exhaustive';
 import { ResultsContext } from 'context/results-context';
 import { useSnackbar } from '@pixie-labs/components';
-import { validateArgs } from 'utils/new-args-utils';
+import { argsForVis, validateArgs } from 'utils/new-args-utils';
 
 export interface ParsedScript extends Omit<Script, 'vis'> {
   visString: string;
@@ -273,12 +273,12 @@ export const ScriptContextProvider: React.FC = ({ children }) => {
     args,
     argsValid: !!script && !!args && validateArgs(script.vis, cleanedArgs) == null,
     setScriptAndArgs: (newScript: Script|ParsedScript, newArgs: Record<string, string|string[]> = args) => {
-      if (typeof newScript.vis === 'string') {
-        setScript({ ...newScript, visString: newScript.vis, vis: parseVis(newScript.vis || '{}') });
-      } else {
-        setScript(newScript as ParsedScript);
-      }
-      push(newScript.id, newArgs);
+      const parsedScript = typeof newScript.vis !== 'string'
+        ? (newScript as ParsedScript)
+        : { ...newScript, visString: newScript.vis, vis: parseVis(newScript.vis || '{}') };
+      setScript(parsedScript);
+
+      push(newScript.id, argsForVis(parsedScript.vis, newArgs));
     },
     routeFor: (s, a) => routeFor(s, a),
     execute,

src/ui/src/utils/new-args-utils.ts

@@ -76,27 +76,19 @@ export function validateArgs(vis: Vis, args: Arguments): VizierQueryError|null {
   return null;
 }
 
-/**
- * Extracts the default values of every variable in the given vis spec.
- * Required variables, which don't specify a default value, are present with an undefined value in the returned object.
- */
-export function defaultValues(vis: Vis): Record<string, string|undefined> {
-  return vis.variables.reduce((a, c) => ({ ...a, [c.name]: c.defaultValue }), {});
-}
-
 /**
  * Merges the given arguments with the defaults for the given Vis spec. Strips/ignores extraneous args.
  * This does NOT check validateArgPresenceAndValues; it's recommended to check that first if trying to run a script.
  */
 export function argsForVis(vis: Vis, args: Arguments): Arguments {
-  if (!vis.variables.length || !Object.keys(args).length) {
+  if (!vis.variables.length) {
     return {};
   }
 
   const outArgs: Arguments = {};
   for (const { name, defaultValue } of vis.variables) {
     // Note: if defaultValue is undefined, the arg is required.
-    outArgs[name] = args[name] ?? defaultValue;
+    outArgs[name] = args[name] ?? defaultValue ?? '';
   }
 
   return outArgs;