Updated the canonical ID of flat conjunctions to match the canonical ID of old style implicit flat conjunctions.

Author: MarkDuckworth

packages/firestore/src/core/filter.ts

@@ -325,6 +325,14 @@ export function canonifyFilter(filter: Filter): string {
       filter.op.toString() +
       canonicalId(filter.value)
     );
+  } else if (compositeFilterIsFlatConjunction(filter)) {
+    // Older SDK versions use an implicit AND operation between their filters.
+    // In the new SDK versions, the developer may use an explicit AND filter.
+    // To stay consistent with the old usages, we add a special case to ensure
+    // the canonical ID for these two are the same. For example:
+    // `col.whereEquals("a", 1).whereEquals("b", 2)` should have the same
+    // canonical ID as `col.where(and(equals("a",1), equals("b",2)))`.
+    return filter.filters.map(filter => canonifyFilter(filter)).join(',');
   } else {
     // filter instanceof CompositeFilter
     const canonicalIdsString = filter.filters

packages/firestore/test/unit/core/filter.test.ts

@@ -25,7 +25,9 @@ import {
   FieldFilter,
   Operator
 } from '../../../src/core/filter';
-import { andFilter, filter, orFilter } from '../../util/helpers';
+import { queryToTarget  } from '../../../src/core/query';
+import { canonifyTarget } from '../../../src/core/target';
+import { andFilter, filter, orFilter, query } from '../../util/helpers';
 
 describe('FieldFilter', () => {
   it('exposes field filter members', () => {
@@ -93,4 +95,14 @@ describe('CompositeFilter', () => {
     expect(compositeFilterIsFlat(orFilter2)).false;
     expect(compositeFilterIsFlatConjunction(orFilter2)).false;
   });
+
+  it('computes canonical id of flat conjunctions', () => {
+    const target1 = query('col', a, b, c);
+
+    const target2 = query('col', andFilter(a, b, c));
+
+    expect(canonifyTarget(queryToTarget(target1))).to.equal(
+      canonifyTarget(queryToTarget(target2))
+    );
+  });
 });