SERVER-25740 Prevent creation of views if featureCompatibilityVersion is 3.2

14 files changed, 140 insertions, 24 deletions

diff --git a/buildscripts/resmokeconfig/suites/views.yml b/buildscripts/resmokeconfig/suites/views.yml
index 2b825ba753b..9a497f0b7ca 100644
--- a/buildscripts/resmokeconfig/suites/views.yml
+++ b/buildscripts/resmokeconfig/suites/views.yml
@@ -17,4 +17,3 @@ executor:
       mongod_options:
         set_parameters:
           enableTestCommands: 1
-          enableViews: 1
diff --git a/buildscripts/resmokeconfig/suites/views_rs.yml b/buildscripts/resmokeconfig/suites/views_rs.yml
index a4cacd25572..b29d8dc66df 100644
--- a/buildscripts/resmokeconfig/suites/views_rs.yml
+++ b/buildscripts/resmokeconfig/suites/views_rs.yml
@@ -23,5 +23,4 @@ executor:
         oplogSize: 511
         set_parameters:
           enableTestCommands: 1
-          enableViews: 1
       num_nodes: 2
diff --git a/jstests/views/durable_view_catalog.js b/jstests/views/durable_view_catalog.js
index c37255d7af9..5c06cf31167 100644
--- a/jstests/views/durable_view_catalog.js
+++ b/jstests/views/durable_view_catalog.js
@@ -12,8 +12,7 @@
     let dbpath = MongoRunner.dataPath + '_durable_view_catalog';
     resetDbpath(dbpath);
 
-    let mongodArgs =
-        {dbpath: dbpath, noCleanData: true, journal: '', setParameter: "enableViews=1"};
+    let mongodArgs = {dbpath: dbpath, noCleanData: true, journal: ''};
 
     // Start a mongod.
     let conn = MongoRunner.runMongod(mongodArgs);
diff --git a/jstests/views/initial_sync_views.js b/jstests/views/initial_sync_views.js
index e5b0ffdae1f..d6557cb5805 100644
--- a/jstests/views/initial_sync_views.js
+++ b/jstests/views/initial_sync_views.js
@@ -10,8 +10,7 @@
     let testName = "initial_sync_views";
     let hostName = getHostName();
 
-    let replTest =
-        new ReplSetTest({name: testName, nodes: 1, nodeOptions: {setParameter: "enableViews=1"}});
+    let replTest = new ReplSetTest({name: testName, nodes: 1});
     replTest.startSet();
     replTest.initiate();
 
diff --git a/jstests/views/views_feature_compatibility_version.js b/jstests/views/views_feature_compatibility_version.js
new file mode 100644
index 00000000000..4e3d5ecb252
--- /dev/null
+++ b/jstests/views/views_feature_compatibility_version.js
@@ -0,0 +1,89 @@
+// Test that views are only enabled if featureCompatibilityVersion is 3.4.
+
+(function() {
+    "use strict";
+
+    const conn = MongoRunner.runMongod({});
+    assert.neq(null, conn, "mongod was unable to start up");
+
+    const viewsDB = conn.getDB("views_feature_compatibility_version");
+    assert.commandWorked(viewsDB.dropDatabase());
+    assert.commandWorked(viewsDB.runCommand({create: "collection"}));
+    assert.commandWorked(viewsDB.runCommand({create: "collection2"}));
+
+    const adminDB = conn.getDB("admin");
+
+    // Ensure the featureCompatibilityVersion is 3.4.
+    assert.commandWorked(adminDB.runCommand({setFeatureCompatibilityVersion: "3.4"}));
+    let res = adminDB.runCommand({getParameter: 1, featureCompatibilityVersion: 1});
+    assert.commandWorked(res);
+    assert.eq("3.4", res.featureCompatibilityVersion);
+
+    // We can create a view when the featureCompatibilityVersion is 3.4.
+    assert.commandWorked(viewsDB.runCommand({create: "view", viewOn: "collection", pipeline: []}));
+
+    // We can update a view when the featureCompatibilityVersion is 3.4.
+    assert.commandWorked(viewsDB.runCommand({collMod: "view", pipeline: []}));
+
+    // We can perform inserts on the system.views collection when the featureCompatibilityVersion is
+    // 3.4.
+    assert.writeOK(viewsDB.system.views.insert(
+        {_id: "views_feature_compatibility_version.view2", viewOn: "collection", pipeline: []}));
+
+    // We can perform updates on the system.views collection when the featureCompatibilityVersion is
+    // 3.4.
+    assert.writeOK(viewsDB.system.views.update({_id: "views_feature_compatibility_version.view2"},
+                                               {$set: {viewOn: "collection2"}}));
+
+    // We can perform deletes on the system.views collection when the featureCompatibilityVersion is
+    // 3.4.
+    assert.writeOK(viewsDB.system.views.remove({_id: "views_feature_compatibility_version.view2"}));
+
+    // We cannot drop the system.views collection when the featureCompatibilityVersion is 3.4.
+    assert.throws(function() {
+        viewsDB.system.views.drop();
+    });
+
+    // Ensure the featureCompatibilityVersion is 3.2.
+    assert.commandWorked(adminDB.runCommand({setFeatureCompatibilityVersion: "3.2"}));
+    res = adminDB.runCommand({getParameter: 1, featureCompatibilityVersion: 1});
+    assert.commandWorked(res);
+    assert.eq("3.2", res.featureCompatibilityVersion);
+
+    // We cannot create views when the featureCompatibilityVersion is 3.2.
+    assert.commandFailed(viewsDB.runCommand({create: "view2", viewOn: "collection", pipeline: []}));
+
+    // We cannot update views when the featureCompatibilityVersion is 3.2.
+    assert.commandFailed(viewsDB.runCommand({collMod: "view", pipeline: []}));
+
+    // We can read from a view when the featureCompatibilityVersion is 3.2.
+    assert.writeOK(viewsDB.collection.insert({a: 5}));
+    assert.eq(5, viewsDB.view.findOne().a);
+
+    // We cannot create a collection with the same name as a view when the
+    // featureCompatibilityVersion is 3.2.
+    assert.commandFailed(viewsDB.runCommand({create: "view"}));
+    assert.writeError(viewsDB.view.insert({a: 5}));
+
+    // We cannot perform inserts on the system.views collection when the featureCompatibilityVersion
+    // is 3.2.
+    assert.writeError(viewsDB.system.views.insert(
+        {_id: "views_feature_compatibility_version.view2", viewOn: "collection", pipeline: []}));
+
+    // We cannot perform updates on the system.views collection when the featureCompatibilityVersion
+    // is 3.2.
+    assert.writeError(viewsDB.system.views.update({_id: "views_feature_compatibility_version.view"},
+                                                  {$set: {viewOn: "collection2"}}));
+
+    // We can drop a view namespace when the featureCompatibilityVersion is 3.2.
+    assert.eq(true, viewsDB.view.drop());
+
+    // We can perform deletes on the system.views collection when the featureCompatibilityVersion is
+    // 3.2.
+    assert.writeOK(viewsDB.system.views.remove({_id: "views_feature_compatibility_version.view"}));
+
+    // We can drop the system.views collection when the featureCompatibilityVersion is 3.2.
+    assert.eq(true, viewsDB.system.views.drop());
+
+    MongoRunner.stopMongod(conn);
+}());
diff --git a/jstests/views/views_legacy.js b/jstests/views/views_legacy.js
index 46154fbdc30..bd31d5bb74e 100644
--- a/jstests/views/views_legacy.js
+++ b/jstests/views/views_legacy.js
@@ -8,7 +8,7 @@
 (function() {
     "use strict";
 
-    let conn = MongoRunner.runMongod({setParameter: "enableViews=1"});
+    let conn = MongoRunner.runMongod({});
 
     let viewsDB = conn.getDB("views_legacy");
     assert.commandWorked(viewsDB.dropDatabase());
diff --git a/jstests/views/views_sharded.js b/jstests/views/views_sharded.js
index 99408fcc9a3..42ca90c4ba3 100644
--- a/jstests/views/views_sharded.js
+++ b/jstests/views/views_sharded.js
@@ -8,11 +8,7 @@
 (function() {
     "use strict";
 
-    let st = new ShardingTest({
-        name: "views_sharded",
-        shards: 2,
-        other: {shardOptions: {setParameter: "enableViews=1"}, enableBalancer: false}
-    });
+    let st = new ShardingTest({name: "views_sharded", shards: 2, other: {enableBalancer: false}});
 
     let mongos = st.s;
     let config = mongos.getDB("config");
diff --git a/src/mongo/db/catalog/database.cpp b/src/mongo/db/catalog/database.cpp
index 41746be60ef..c9482569f73 100644
--- a/src/mongo/db/catalog/database.cpp
+++ b/src/mongo/db/catalog/database.cpp
@@ -387,6 +387,14 @@ Status Database::dropCollection(OperationContext* txn, StringData fullns) {
                 if (_profile != 0)
                     return Status(ErrorCodes::IllegalOperation,
                                   "turn off profiling before dropping system.profile collection");
+            } else if (nss.isSystemDotViews()) {
+                if (serverGlobalParams.featureCompatibilityVersion.load() !=
+                    ServerGlobalParams::FeatureCompatibilityVersion_32) {
+                    return Status(ErrorCodes::IllegalOperation,
+                                  "The featureCompatibilityVersion must be 3.2 to drop the "
+                                  "system.views collection. See "
+                                  "http://dochub.mongodb.org/core/3.4-feature-compatibility.");
+                }
             } else {
                 return Status(ErrorCodes::IllegalOperation, "can't drop system ns");
             }
diff --git a/src/mongo/db/namespace_string.cpp b/src/mongo/db/namespace_string.cpp
index 95d600fb27b..27495baa9d0 100644
--- a/src/mongo/db/namespace_string.cpp
+++ b/src/mongo/db/namespace_string.cpp
@@ -96,7 +96,7 @@ bool legalClientSystemNS(StringData ns) {
     if (ns.find(".system.js") != string::npos)
         return true;
 
-    if (nsToCollectionSubstring(ns) == "system.views")
+    if (nsToCollectionSubstring(ns) == NamespaceString::kSystemDotViewsCol)
         return true;
 
     return false;
@@ -104,6 +104,7 @@ bool legalClientSystemNS(StringData ns) {
 
 const StringData NamespaceString::kAdminDb = "admin"_sd;
 const StringData NamespaceString::kLocalDb = "local"_sd;
+constexpr StringData NamespaceString::kSystemDotViewsCol;
 
 const NamespaceString NamespaceString::kConfigCollectionNamespace(kConfigCollection);
 
diff --git a/src/mongo/db/namespace_string.h b/src/mongo/db/namespace_string.h
index e4b3be50075..93810d6307b 100644
--- a/src/mongo/db/namespace_string.h
+++ b/src/mongo/db/namespace_string.h
@@ -63,6 +63,9 @@ public:
     // Namespace for the local database
     static const StringData kLocalDb;
 
+    // Name for the system views collection
+    static constexpr StringData kSystemDotViewsCol = "system.views"_sd;
+
     // Namespace for storing configuration data, which needs to be replicated if the server is
     // running as a replica set. Documents in this collection should represent some configuration
     // state of the server, which needs to be recovered/consulted at startup. Each document in this
@@ -162,6 +165,9 @@ public:
     bool isSystemDotProfile() const {
         return coll() == "system.profile";
     }
+    bool isSystemDotViews() const {
+        return coll() == kSystemDotViewsCol;
+    }
     bool isConfigDB() const {
         return db() == "config";
     }
diff --git a/src/mongo/db/op_observer.cpp b/src/mongo/db/op_observer.cpp
index 8defc1c71fe..f3e1a3729c8 100644
--- a/src/mongo/db/op_observer.cpp
+++ b/src/mongo/db/op_observer.cpp
@@ -91,6 +91,7 @@ void OpObserver::onInserts(OperationContext* txn,
     }
     if (nss.coll() == DurableViewCatalog::viewsCollectionName()) {
         DurableViewCatalog::onExternalChange(txn, nss);
+        DurableViewCatalog::confirm34FeatureCompatibilityVersion();
     }
 }
 
@@ -117,6 +118,7 @@ void OpObserver::onUpdate(OperationContext* txn, const OplogUpdateEntryArgs& arg
     NamespaceString nss(args.ns);
     if (nss.coll() == DurableViewCatalog::viewsCollectionName()) {
         DurableViewCatalog::onExternalChange(txn, nss);
+        DurableViewCatalog::confirm34FeatureCompatibilityVersion();
     }
 
     if (args.ns == FeatureCompatibilityVersion::kCollection) {
diff --git a/src/mongo/db/views/durable_view_catalog.cpp b/src/mongo/db/views/durable_view_catalog.cpp
index ba84432b7cf..7f7648160df 100644
--- a/src/mongo/db/views/durable_view_catalog.cpp
+++ b/src/mongo/db/views/durable_view_catalog.cpp
@@ -59,6 +59,15 @@ void DurableViewCatalog::onExternalChange(OperationContext* txn, const Namespace
     }
 }
 
+void DurableViewCatalog::confirm34FeatureCompatibilityVersion() {
+    uassert(40307,
+            "Cannot perform inserts or updates on system.views collection when "
+            "the featureCompatibilityVersion is 3.2. See "
+            "http://dochub.mongodb.org/core/3.4-feature-compatibility.",
+            serverGlobalParams.featureCompatibilityVersion.load() !=
+                ServerGlobalParams::FeatureCompatibilityVersion_32);
+}
+
 // DurableViewCatalogImpl
 
 const std::string& DurableViewCatalogImpl::getName() const {
diff --git a/src/mongo/db/views/durable_view_catalog.h b/src/mongo/db/views/durable_view_catalog.h
index 1ea7268f2ee..3ca577cdfbb 100644
--- a/src/mongo/db/views/durable_view_catalog.h
+++ b/src/mongo/db/views/durable_view_catalog.h
@@ -32,13 +32,13 @@
 
 #include "mongo/base/status.h"
 #include "mongo/base/string_data.h"
+#include "mongo/db/namespace_string.h"
 #include "mongo/stdx/functional.h"
 
 namespace mongo {
 
 class BSONObj;
 class Database;
-class NamespaceString;
 class OperationContext;
 
 /**
@@ -49,7 +49,7 @@ class OperationContext;
 class DurableViewCatalog {
 public:
     static constexpr StringData viewsCollectionName() {
-        return "system.views"_sd;
+        return NamespaceString::kSystemDotViewsCol;
     }
 
     /**
@@ -58,6 +58,11 @@ public:
      */
     static void onExternalChange(OperationContext* txn, const NamespaceString& name);
 
+    /**
+     * Throws if featureCompatibilityVersion is 3.2.
+     */
+    static void confirm34FeatureCompatibilityVersion();
+
     using Callback = stdx::function<void(const BSONObj& view)>;
     virtual Status iterate(OperationContext* txn, Callback callback) = 0;
     virtual void upsert(OperationContext* txn,
diff --git a/src/mongo/db/views/view_catalog.cpp b/src/mongo/db/views/view_catalog.cpp
index 9e4ad5c8b8f..6e8344059f9 100644
--- a/src/mongo/db/views/view_catalog.cpp
+++ b/src/mongo/db/views/view_catalog.cpp
@@ -47,15 +47,8 @@
 #include "mongo/db/views/view.h"
 #include "mongo/util/log.h"
 
-namespace {
-bool enableViews = true;
-}  // namespace
-
 namespace mongo {
 
-ExportedServerParameter<bool, ServerParameterType::kStartupOnly> enableViewsParameter(
-    ServerParameterSet::getGlobal(), "enableViews", &enableViews);
-
 Status ViewCatalog::reloadIfNeeded(OperationContext* txn) {
     stdx::lock_guard<stdx::mutex> lk(_mutex);
     return _reloadIfNeeded_inlock(txn);
@@ -178,8 +171,12 @@ Status ViewCatalog::createView(OperationContext* txn,
                                const BSONArray& pipeline) {
     stdx::lock_guard<stdx::mutex> lk(_mutex);
 
-    if (!enableViews)
-        return Status(ErrorCodes::CommandNotSupported, "View support not enabled");
+    if (serverGlobalParams.featureCompatibilityVersion.load() ==
+        ServerGlobalParams::FeatureCompatibilityVersion_32) {
+        return Status(ErrorCodes::CommandNotSupported,
+                      "Cannot create view when the featureCompatibilityVersion is 3.2. See "
+                      "http://dochub.mongodb.org/core/3.4-feature-compatibility.");
+    }
 
     if (viewName.db() != viewOn.db())
         return Status(ErrorCodes::BadValue,
@@ -201,6 +198,13 @@ Status ViewCatalog::modifyView(OperationContext* txn,
                                const BSONArray& pipeline) {
     stdx::lock_guard<stdx::mutex> lk(_mutex);
 
+    if (serverGlobalParams.featureCompatibilityVersion.load() ==
+        ServerGlobalParams::FeatureCompatibilityVersion_32) {
+        return Status(ErrorCodes::CommandNotSupported,
+                      "Cannot modify view when the featureCompatibilityVersion is 3.2. See "
+                      "http://dochub.mongodb.org/core/3.4-feature-compatibility.");
+    }
+
     if (viewName.db() != viewOn.db())
         return Status(ErrorCodes::BadValue,
                       "View must be created on a view or collection in the same database");