(core) tolerate table renames when displaying differences

Summary:
This makes data diff rendering robust to changes in the names of tables.
It does not yet show information about those changes, but at least it
won't fail to show table content changes.

Added a missing case to ActionSummary concatenation that came up in
testing.

Test Plan: added test, updated test

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2661

app/client/components/BaseView.js

@@ -7,7 +7,7 @@ var {getSelectionDesc} = require('app/common/DocActions');
 var {nativeCompare, roundDownToMultiple, waitObs} = require('app/common/gutil');
 var gristTypes = require('app/common/gristTypes');
 var koUtil = require('../lib/koUtil');
-var tableUtil    = require('../lib/tableUtil');
+var tableUtil = require('../lib/tableUtil');
 var {DataRowModel} = require('../models/DataRowModel');
 var {DynamicQuerySet} = require('../models/QuerySet');
 var {SortFunc} = require('app/common/SortFunc');

app/client/models/DataTableModelWithDiff.ts

@@ -5,7 +5,7 @@ import { TableRec } from 'app/client/models/entities/TableRec';
 import { TableQuerySets } from 'app/client/models/QuerySet';
 import { RowGrouping, SortedRowSet } from 'app/client/models/rowset';
 import { TableData } from 'app/client/models/TableData';
-import { createEmptyTableDelta, TableDelta } from 'app/common/ActionSummary';
+import { createEmptyTableDelta, getTableIdAfter, getTableIdBefore, TableDelta } from 'app/common/ActionSummary';
 import { DisposableWithEvents } from 'app/common/DisposableWithEvents';
 import { CellVersions, UserAction } from 'app/common/DocActions';
 import { GristObjCode } from "app/common/gristTypes";
@@ -40,12 +40,15 @@ export class ExtraRows {
   }
 
   public constructor(readonly tableId: string, readonly comparison?: DocStateComparisonDetails) {
-    this.leftTableDelta = this.comparison?.leftChanges?.tableDeltas[this.tableId];
-    this.rightTableDelta = this.comparison?.rightChanges?.tableDeltas[this.tableId];
-    this.rightAddRows = new Set(this.rightTableDelta && this.rightTableDelta.addRows.map(id => -id*2));
-    this.rightRemoveRows = new Set(this.rightTableDelta && this.rightTableDelta.removeRows);
-    this.leftAddRows = new Set(this.leftTableDelta && this.leftTableDelta.addRows);
-    this.leftRemoveRows = new Set(this.leftTableDelta && this.leftTableDelta.removeRows.map(id => -id*2 -1));
+    const remoteTableId = getRemoteTableId(tableId, comparison);
+    this.leftTableDelta = this.comparison?.leftChanges?.tableDeltas[tableId];
+    if (remoteTableId) {
+      this.rightTableDelta = this.comparison?.rightChanges?.tableDeltas[remoteTableId];
+    }
+    this.rightAddRows = new Set(this.rightTableDelta?.addRows.map(id => -id*2));
+    this.rightRemoveRows = new Set(this.rightTableDelta?.removeRows);
+    this.leftAddRows = new Set(this.leftTableDelta?.addRows);
+    this.leftRemoveRows = new Set(this.leftTableDelta?.removeRows.map(id => -id*2 -1));
   }
 
   /**
@@ -98,10 +101,12 @@ export class DataTableModelWithDiff extends DisposableWithEvents implements Data
     this.tableMetaRow = core.tableMetaRow;
     this.tableQuerySets = core.tableQuerySets;
     this.docModel = core.docModel;
+    const tableId = core.tableData.tableId;
+    const remoteTableId = getRemoteTableId(tableId, comparison) || '';
     this.tableData = new TableDataWithDiff(
       core.tableData,
-      comparison.leftChanges.tableDeltas[core.tableData.tableId] || createEmptyTableDelta(),
-      comparison.rightChanges.tableDeltas[core.tableData.tableId] || createEmptyTableDelta()) as any;
+      comparison.leftChanges.tableDeltas[tableId] || createEmptyTableDelta(),
+      comparison.rightChanges.tableDeltas[remoteTableId] || createEmptyTableDelta()) as any;
     this.isLoaded = core.isLoaded;
     this._wrappedModel = new DataTableModel(this.docModel, this.tableData, this.tableMetaRow);
   }
@@ -244,3 +249,13 @@ function newValue(delta: CellDelta) {
   if (delta[1] === '?') { return null; }
   return delta[1]?.[0];
 }
+
+/**
+ * Figure out the id of the specified table in the remote document.
+ * Returns null if table is deleted or unknown in the remote document.
+ */
+function getRemoteTableId(tableId: string, comparison?: DocStateComparisonDetails) {
+  if (!comparison) { return tableId; }
+  const parentTableId = getTableIdBefore(comparison.leftChanges.tableRenames, tableId);
+  return getTableIdAfter(comparison.rightChanges.tableRenames, parentTableId);
+}

app/common/ActionSummary.ts

@@ -233,3 +233,25 @@ export function getAffectedTables(summary: ActionSummary): string[] {
     ...Object.keys(summary.tableDeltas)
   ];
 }
+
+/**
+ * Given a tableId from after the specified renames, figure out what the tableId was before
+ * the renames.  Returns null if table didn't exist.
+ */
+export function getTableIdBefore(renames: LabelDelta[], tableIdAfter: string|null): string|null {
+  if (tableIdAfter === null) { return tableIdAfter; }
+  const rename = renames.find(rename => rename[1] === tableIdAfter);
+  return rename ? rename[0] : tableIdAfter;
+}
+
+/**
+ * Given a tableId from before the specified renames, figure out what the tableId is after
+ * the renames.  Returns null if there is no valid tableId to return.
+ */
+export function getTableIdAfter(renames: LabelDelta[], tableIdBefore: string|null): string|null {
+  if (tableIdBefore === null) { return tableIdBefore; }
+  const rename = renames.find(rename => rename[0] === tableIdBefore);
+  const tableIdAfter = rename ? rename[1] : tableIdBefore;
+  if (tableIdAfter?.startsWith('-')) { return null; }
+  return tableIdAfter;
+}

app/server/lib/ActionSummary.ts

@@ -246,12 +246,14 @@ function planNameMerge(names1: LabelDelta[], names2: LabelDelta[]): NameMerge {
     result.rename1.set(after1, after2);
     result.merge.push([before1, after2]);
   }
-  // Look through part 2 for any changes not already covered.  We won't need to do any
-  // renaming since table/column names at end of part 2 are just what we want.
+  // Look through part 2 for any changes not already covered.
   for (const [before2, after2] of names2) {
     if (!before2 && !after2) { throw new Error("invalid name change found"); }
     if (before2 && names1ByFinalName[before2]) { continue; }  // Already handled
     result.merge.push([before2, after2]);
+    // If table/column is renamed in part 2, and name was stable in part 1,
+    // rekey any information about it in part 1.
+    if (before2 && after2) { result.rename1.set(before2, after2); }
   }
   // For neatness, sort the merge order. Not essential.
   result.merge = sortBy(result.merge, ([a, b]) => [a || "", b || ""]);