From fd15f771ef8266f2f8852cd1a585106add862e40 Mon Sep 17 00:00:00 2001
From: Andrew Kingston <andrew@kingston.dev>
Date: Thu, 26 Oct 2023 19:03:04 +0100
Subject: [PATCH] Refactor how relationship cells fetch and cache primary
 display columns to fix issues with store stale data

---
 .../grid/cells/RelationshipCell.svelte        | 25 ++--------
 .../src/components/grid/stores/cache.js       | 49 +++++++++++++++++++
 .../src/components/grid/stores/index.js       |  2 +
 3 files changed, 56 insertions(+), 20 deletions(-)
 create mode 100644 packages/frontend-core/src/components/grid/stores/cache.js

diff --git a/packages/frontend-core/src/components/grid/cells/RelationshipCell.svelte b/packages/frontend-core/src/components/grid/cells/RelationshipCell.svelte
index 925c840478..0db022777f 100644
--- a/packages/frontend-core/src/components/grid/cells/RelationshipCell.svelte
+++ b/packages/frontend-core/src/components/grid/cells/RelationshipCell.svelte
@@ -1,27 +1,10 @@
-<script context="module">
-  // We can create a module level cache for all relationship cells to avoid
-  // having to fetch the table definition one time for each cell
-  let primaryDisplayCache = {}
-
-  const getPrimaryDisplayForTableId = async (API, tableId) => {
-    if (primaryDisplayCache[tableId]) {
-      return primaryDisplayCache[tableId]
-    }
-    const definition = await API.fetchTableDefinition(tableId)
-    const primaryDisplay =
-      definition?.primaryDisplay || definition?.schema?.[0]?.name
-    primaryDisplayCache[tableId] = primaryDisplay
-    return primaryDisplay
-  }
-</script>
-
 <script>
   import { getColor } from "../lib/utils"
   import { onMount, getContext } from "svelte"
   import { Icon, Input, ProgressCircle, clickOutside } from "@budibase/bbui"
   import { debounce } from "../../../utils/utils"
 
-  const { API, dispatch } = getContext("grid")
+  const { API, dispatch, cache } = getContext("grid")
 
   export let value
   export let api
@@ -147,7 +130,9 @@
     // Find the primary display for the related table
     if (!primaryDisplay) {
       searching = true
-      primaryDisplay = await getPrimaryDisplayForTableId(API, schema.tableId)
+      primaryDisplay = await cache.actions.getPrimaryDisplayForTableId(
+        schema.tableId
+      )
     }
 
     // Show initial list of results
@@ -195,7 +180,7 @@
   const toggleRow = async row => {
     if (value?.some(x => x._id === row._id)) {
       // If the row is already included, remove it and update the candidate
-      // row to be the the same position if possible
+      // row to be the same position if possible
       if (oneRowOnly) {
         await onChange([])
       } else {
diff --git a/packages/frontend-core/src/components/grid/stores/cache.js b/packages/frontend-core/src/components/grid/stores/cache.js
new file mode 100644
index 0000000000..7d48627314
--- /dev/null
+++ b/packages/frontend-core/src/components/grid/stores/cache.js
@@ -0,0 +1,49 @@
+export const createActions = context => {
+  const { API } = context
+
+  // Cache for the primary display columns of different tables.
+  // If we ever need to cache table definitions for other purposes then we can
+  // expand this to be a more generic cache.
+  let primaryDisplayCache = {}
+
+  const resetPrimaryDisplayCache = () => {
+    primaryDisplayCache = {}
+  }
+
+  const getPrimaryDisplayForTableId = async tableId => {
+    // If we've never encountered this tableId before then store a promise that
+    // resolves to the primary display so that subsequent invocations before the
+    // promise completes can reuse this promise
+    if (!primaryDisplayCache[tableId]) {
+      primaryDisplayCache[tableId] = new Promise(resolve => {
+        API.fetchTableDefinition(tableId).then(def => {
+          const display = def?.primaryDisplay || def?.schema?.[0]?.name
+          primaryDisplayCache[tableId] = display
+          resolve(display)
+        })
+      })
+    }
+
+    // We await the result so that we account for both promises and primitives
+    return await primaryDisplayCache[tableId]
+  }
+
+  return {
+    cache: {
+      actions: {
+        getPrimaryDisplayForTableId,
+        resetPrimaryDisplayCache,
+      },
+    },
+  }
+}
+
+export const initialise = context => {
+  const { datasource, cache } = context
+
+  // Wipe the caches whenever the datasource changes to ensure we aren't
+  // storing any stale information
+  datasource.subscribe(() => {
+    cache.actions.resetPrimaryDisplayCache()
+  })
+}
diff --git a/packages/frontend-core/src/components/grid/stores/index.js b/packages/frontend-core/src/components/grid/stores/index.js
index 10fe932aab..6dfff6531b 100644
--- a/packages/frontend-core/src/components/grid/stores/index.js
+++ b/packages/frontend-core/src/components/grid/stores/index.js
@@ -19,6 +19,7 @@ import * as Datasource from "./datasource"
 import * as Table from "./datasources/table"
 import * as ViewV2 from "./datasources/viewV2"
 import * as NonPlus from "./datasources/nonPlus"
+import * as Cache from "./cache"
 
 const DependencyOrderedStores = [
   Sort,
@@ -42,6 +43,7 @@ const DependencyOrderedStores = [
   Clipboard,
   Config,
   Notifications,
+  Cache,
 ]
 
 export const attachStores = context => {