Fix MutationQueue issue resulting in re-sending acknowledged writes. (#909)

Port of: https://github.com/firebase/firebase-js-sdk/pull/559
Should address #772 once released.

getNextMutationBatchAfterBatchId() was not respecting
highestAcknowledgedBatchId and therefore we were resending writes after the
network was disabled / re-enabled.

2 files changed, 208 insertions, 0 deletions

diff --git a/Firestore/Example/Tests/Local/FSTMutationQueueTests.mm b/Firestore/Example/Tests/Local/FSTMutationQueueTests.mm
index 7d305d0..f5294d5 100644
--- a/Firestore/Example/Tests/Local/FSTMutationQueueTests.mm
+++ b/Firestore/Example/Tests/Local/FSTMutationQueueTests.mm
@@ -217,6 +217,22 @@ NS_ASSUME_NONNULL_BEGIN
   XCTAssertNil(notFound);
 }
 
+- (void)testNextMutationBatchAfterBatchIDSkipsAcknowledgedBatches {
+  if ([self isTestBaseClass]) return;
+
+  NSMutableArray<FSTMutationBatch *> *batches = [self createBatches:3];
+  XCTAssertEqualObjects([self.mutationQueue nextMutationBatchAfterBatchID:kFSTBatchIDUnknown],
+                        batches[0]);
+
+  [self acknowledgeBatch:batches[0]];
+  XCTAssertEqualObjects([self.mutationQueue nextMutationBatchAfterBatchID:kFSTBatchIDUnknown],
+                        batches[1]);
+  XCTAssertEqualObjects([self.mutationQueue nextMutationBatchAfterBatchID:batches[0].batchID],
+                        batches[1]);
+  XCTAssertEqualObjects([self.mutationQueue nextMutationBatchAfterBatchID:batches[1].batchID],
+                        batches[2]);
+}
+
 - (void)testAllMutationBatchesThroughBatchID {
   if ([self isTestBaseClass]) return;
 
diff --git a/Firestore/Example/Tests/SpecTests/json/write_spec_test.json b/Firestore/Example/Tests/SpecTests/json/write_spec_test.json
index 8e3f5d5..d4d1e7c 100644
--- a/Firestore/Example/Tests/SpecTests/json/write_spec_test.json
+++ b/Firestore/Example/Tests/SpecTests/json/write_spec_test.json
@@ -3407,6 +3407,198 @@
       }
     ]
   },
+  "Held writes are not re-sent after disable/enable network.": {
+    "describeName": "Writes:",
+    "itName": "Held writes are not re-sent after disable/enable network.",
+    "tags": [],
+    "config": {
+      "useGarbageCollection": true
+    },
+    "steps": [
+      {
+        "userListen": [
+          2,
+          {
+            "path": "collection",
+            "filters": [],
+            "orderBys": []
+          }
+        ],
+        "stateExpect": {
+          "activeTargets": {
+            "2": {
+              "query": {
+                "path": "collection",
+                "filters": [],
+                "orderBys": []
+              },
+              "resumeToken": ""
+            }
+          }
+        }
+      },
+      {
+        "watchAck": [
+          2
+        ]
+      },
+      {
+        "watchEntity": {
+          "docs": [],
+          "targets": [
+            2
+          ]
+        }
+      },
+      {
+        "watchCurrent": [
+          [
+            2
+          ],
+          "resume-token-500"
+        ],
+        "watchSnapshot": 500,
+        "expect": [
+          {
+            "query": {
+              "path": "collection",
+              "filters": [],
+              "orderBys": []
+            },
+            "errorCode": 0,
+            "fromCache": false,
+            "hasPendingWrites": false
+          }
+        ]
+      },
+      {
+        "userSet": [
+          "collection/a",
+          {
+            "v": 1
+          }
+        ],
+        "expect": [
+          {
+            "query": {
+              "path": "collection",
+              "filters": [],
+              "orderBys": []
+            },
+            "added": [
+              [
+                "collection/a",
+                0,
+                {
+                  "v": 1
+                },
+                "local"
+              ]
+            ],
+            "errorCode": 0,
+            "fromCache": false,
+            "hasPendingWrites": true
+          }
+        ]
+      },
+      {
+        "writeAck": {
+          "version": 1000,
+          "expectUserCallback": true
+        },
+        "stateExpect": {
+          "writeStreamRequestCount": 2
+        }
+      },
+      {
+        "enableNetwork": false,
+        "stateExpect": {
+          "activeTargets": {},
+          "limboDocs": [],
+          "writeStreamRequestCount": 3
+        },
+        "expect": [
+          {
+            "query": {
+              "path": "collection",
+              "filters": [],
+              "orderBys": []
+            },
+            "errorCode": 0,
+            "fromCache": true,
+            "hasPendingWrites": true
+          }
+        ]
+      },
+      {
+        "enableNetwork": true,
+        "stateExpect": {
+          "activeTargets": {
+            "2": {
+              "query": {
+                "path": "collection",
+                "filters": [],
+                "orderBys": []
+              },
+              "resumeToken": "resume-token-500"
+            }
+          },
+          "writeStreamRequestCount": 3
+        }
+      },
+      {
+        "watchAck": [
+          2
+        ]
+      },
+      {
+        "watchEntity": {
+          "docs": [
+            [
+              "collection/a",
+              1000,
+              {
+                "v": 1
+              }
+            ]
+          ],
+          "targets": [
+            2
+          ]
+        }
+      },
+      {
+        "watchCurrent": [
+          [
+            2
+          ],
+          "resume-token-2000"
+        ],
+        "watchSnapshot": 2000,
+        "expect": [
+          {
+            "query": {
+              "path": "collection",
+              "filters": [],
+              "orderBys": []
+            },
+            "metadata": [
+              [
+                "collection/a",
+                1000,
+                {
+                  "v": 1
+                }
+              ]
+            ],
+            "errorCode": 0,
+            "fromCache": false,
+            "hasPendingWrites": false
+          }
+        ]
+      }
+    ]
+  },
   "Held writes are released when there are no queries left.": {
     "describeName": "Writes:",
     "itName": "Held writes are released when there are no queries left.",