From ada4f4181bd03b1243398857a8e8d8871b35a9ce Mon Sep 17 00:00:00 2001
From: Christophe Diederichs <45171645+chm-diederichs@users.noreply.github.com>
Date: Wed, 7 Aug 2024 11:14:27 +0200
Subject: [PATCH] Make sure member count is accurate when writer rejoining
 (#167)

* add test for removing and rejoining

* removed writer does not count as tracked
---
 lib/system.js |  4 ++--
 test/basic.js | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/lib/system.js b/lib/system.js
index e2a7cacd..53bca119 100644
--- a/lib/system.js
+++ b/lib/system.js
@@ -305,11 +305,11 @@ module.exports = class SystemView extends ReadyResource {
       cas (older, newer) {
         if (older === null) return true
 
-        wasTracked = true
-
         const o = older.value
         const n = newer.value
 
+        if (!o.isRemoved) wasTracked = true
+
         if (length === 0 && o.length) length = o.length
 
         return o.isRemoved !== n.isRemoved || o.isIndexer !== n.isIndexer || o.length !== n.length
diff --git a/test/basic.js b/test/basic.js
index b453a4e3..870f025e 100644
--- a/test/basic.js
+++ b/test/basic.js
@@ -1088,6 +1088,31 @@ test('basic - remove writer', async t => {
   t.is(b.system.members, c.system.members)
 })
 
+test('basic - remove and rejoin writer', async t => {
+  const { bases } = await create(2, t, { apply: applyWithRemove, open: null })
+  const [a, b] = bases
+
+  await addWriter(a, b, false)
+  await confirm([a, b])
+
+  t.is(a.system.members, 2)
+
+  await a.append({ remove: b4a.toString(b.local.key, 'hex') })
+  await confirm([a, b])
+
+  t.is(a.system.members, 1)
+
+  await addWriter(a, b, false)
+  await confirm([a, b])
+
+  t.is(a.system.members, 2)
+
+  await a.append({ remove: b4a.toString(b.local.key, 'hex') })
+  await confirm([a, b])
+
+  t.is(a.system.members, 1)
+})
+
 test('basic - non-indexer writer removes themselves', async t => {
   const { bases } = await create(2, t, { apply: applyWithRemove, open: null })
   const [a, b] = bases