Do not emit conflict events for mutual deletions

No changes can be lost when documents are deleted on both ends

Author: raucao

src/sync.ts

@@ -507,17 +507,21 @@ export class Sync {
       node = mergeMutualDeletion(node);
       delete node.remote;
     } else if (node.remote.body !== undefined) {
-      log('[Sync] Emitting conflict event');
-      setTimeout(this.rs.local.emitChange.bind(this.rs.local), 10, {
-        origin:          'conflict',
-        path:            node.path,
-        oldValue:        node.local.body,
-        newValue:        node.remote.body,
-        lastCommonValue: node.common.body,
-        oldContentType:  node.local.contentType,
-        newContentType:  node.remote.contentType,
-        lastCommonContentType: node.common.contentType
-      });
+      if (node.remote.body === false && node.local?.body === false) {
+        // Deleted on both sides, nothing to do
+      } else {
+        log('[Sync] Emitting conflict event');
+        setTimeout(this.rs.local.emitChange.bind(this.rs.local), 10, {
+          origin:          'conflict',
+          path:            node.path,
+          oldValue:        node.local.body,
+          newValue:        node.remote.body,
+          lastCommonValue: node.common.body,
+          oldContentType:  node.local.contentType,
+          newContentType:  node.remote.contentType,
+          lastCommonContentType: node.common.contentType
+        });
+      }
 
       if (node.remote.body === false) {
         node.common = {};

test/unit/sync.test.mjs

@@ -949,6 +949,56 @@ describe("Sync", function() {
         }, 20);
       });
     });
+
+    describe("when node was also deleted on remote", function() {
+      beforeEach(function() {
+        this.emitChange = sinon.spy(this.rs.local, "emitChange");
+
+        this.rs.sync.autoMergeDocument({
+          path: "foo",
+          common: { body: "foo", contentType: "bloo", revision: "common" },
+          local: { body: false },
+          remote: { body: false }
+        });
+      });
+
+      it("does not emit a conflict event", function(done) {
+        setTimeout(() => {
+          expect(this.emitChange.called).to.be.false;
+          done();
+        }, 20);
+      });
+    });
+
+    describe("when node was changed on remote, but deleted locally", function() {
+      beforeEach(function() {
+        this.emitChange = sinon.spy(this.rs.local, "emitChange");
+
+        this.rs.sync.autoMergeDocument({
+          path: "foo",
+          remote: { body: "bar", contentType: "text/plain", revision: "newrev"},
+          common: { body: "foo", contentType: "text/plain", revision: "common" },
+          local: { body: false }
+        });
+      });
+
+      it("emits a conflict event", function(done) {
+        setTimeout(() => {
+          expect(this.emitChange.called).to.be.true;
+          expect(this.emitChange.getCall(0).firstArg).to.deep.equal({
+            origin: "conflict",
+            path: "foo",
+            oldValue: false,
+            newValue: "bar",
+            lastCommonValue: "foo",
+            oldContentType: undefined,
+            newContentType: "text/plain",
+            lastCommonContentType: "text/plain"
+          });
+          done();
+        }, 20);
+      });
+    });
   });
 
   describe("#autoMergeFolder", function() {