RUST-2190 Remove support for server 4.0

.evergreen/config.yml

@@ -94,9 +94,9 @@ buildvariants:
       SSL: ssl
     tasks:
       # Ubuntu 22.04 does not support MongoDB versions below 6.0.
-      - name: .standalone !.4.0 !.4.2 !.4.4 !.5.0
-      - name: .replicaset !.4.0 !.4.2 !.4.4 !.5.0
-      - name: .sharded !.4.0 !.4.2 !.4.4 !.5.0
+      - name: .standalone !.4.2 !.4.4 !.5.0
+      - name: .replicaset !.4.2 !.4.4 !.5.0
+      - name: .sharded !.4.2 !.4.4 !.5.0
 
   - name: macos-14.00
     display_name: "MacOS 14.00"
@@ -200,8 +200,8 @@ buildvariants:
     tasks:
       # The Stable API was introduced in MongoDB version 5.0. Drivers Evergreen Tools only supports
       # setting REQUIRE_API_VERSION on standalones and sharded clusters.
-      - .standalone !.4.0 !.4.2 !.4.4
-      - .sharded !.4.0 !.4.2 !.4.4
+      - .standalone !.4.2 !.4.4
+      - .sharded !.4.2 !.4.4
 
   - name: sync-api
     display_name: "Sync API"

.evergreen/generate-tasks/.gitignore

@@ -1 +1,2 @@
 target
+Cargo.lock

.evergreen/generate-tasks/src/main.rs

@@ -1,6 +1,4 @@
-static VERSIONS: &[&str] = &[
-    "4.0", "4.2", "4.4", "5.0", "6.0", "7.0", "8.0", "rapid", "latest",
-];
+static VERSIONS: &[&str] = &["4.2", "4.4", "5.0", "6.0", "7.0", "8.0", "rapid", "latest"];
 
 static TOPOLOGIES: &[(&str, &str)] = &[
     ("standalone", "server"),

.evergreen/suite-tasks.yml

@@ -3,15 +3,6 @@
 
 tasks:
 
-  - name: test-4.0-standalone
-    tags: [4.0, standalone]
-    commands:
-      - func: "bootstrap mongo-orchestration"
-        vars:
-          MONGODB_VERSION: 4.0
-          TOPOLOGY: server
-      - func: "run driver test suite"
-
   - name: test-4.2-standalone
     tags: [4.2, standalone]
     commands:
@@ -84,15 +75,6 @@ tasks:
           TOPOLOGY: server
       - func: "run driver test suite"
 
-  - name: test-4.0-replicaset
-    tags: [4.0, replicaset]
-    commands:
-      - func: "bootstrap mongo-orchestration"
-        vars:
-          MONGODB_VERSION: 4.0
-          TOPOLOGY: replica_set
-      - func: "run driver test suite"
-
   - name: test-4.2-replicaset
     tags: [4.2, replicaset]
     commands:
@@ -165,15 +147,6 @@ tasks:
           TOPOLOGY: replica_set
       - func: "run driver test suite"
 
-  - name: test-4.0-sharded
-    tags: [4.0, sharded]
-    commands:
-      - func: "bootstrap mongo-orchestration"
-        vars:
-          MONGODB_VERSION: 4.0
-          TOPOLOGY: sharded_cluster
-      - func: "run driver test suite"
-
   - name: test-4.2-sharded
     tags: [4.2, sharded]
     commands:

README.md

@@ -11,7 +11,7 @@ For more details, including features, runnable examples, troubleshooting resourc
 ### Requirements
 
 - Rust 1.83.0+ (See the [MSRV policy](#minimum-supported-rust-version-msrv-policy) for more information)
-- MongoDB 4.0+
+- MongoDB 4.2+
 
 #### Supported Platforms
 

src/action/find_and_modify.rs

@@ -61,8 +61,7 @@ impl<T: DeserializeOwned + Send + Sync> Collection<T> {
 
     /// Atomically finds up to one document in the collection matching `filter` and updates it.
     /// Both `Document` and `Vec<Document>` implement `Into<UpdateModifications>`, so either can be
-    /// passed in place of constructing the enum case. Note: pipeline updates are only supported
-    /// in MongoDB 4.2+.
+    /// passed in place of constructing the enum case.
     ///
     /// This operation will retry once upon failure if the connection and encountered error support
     /// retryability. See the documentation
@@ -133,8 +132,7 @@ impl<T: DeserializeOwned + Send + Sync> crate::sync::Collection<T> {
 
     /// Atomically finds up to one document in the collection matching `filter` and updates it.
     /// Both `Document` and `Vec<Document>` implement `Into<UpdateModifications>`, so either can be
-    /// passed in place of constructing the enum case. Note: pipeline updates are only supported
-    /// in MongoDB 4.2+.
+    /// passed in place of constructing the enum case.
     ///
     /// This operation will retry once upon failure if the connection and encountered error support
     /// retryability. See the documentation

src/action/transaction.rs

@@ -19,9 +19,6 @@ impl ClientSession {
     /// [`crate::error::TRANSIENT_TRANSACTION_ERROR`] label. This label indicates that the entire
     /// transaction can be retried with a reasonable expectation that it will succeed.
     ///
-    /// Transactions on replica sets are supported on MongoDB 4.0+. Transactions on sharded
-    /// clusters are supported on MongoDB 4.2+.
-    ///
     /// ```rust
     /// # use mongodb::{bson::{doc, Document}, error::Result, Client, ClientSession};
     /// #

src/action/update.rs

@@ -20,8 +20,7 @@ where
     /// Updates all documents matching `query` in the collection.
     ///
     /// Both `Document` and `Vec<Document>` implement `Into<UpdateModifications>`, so either can be
-    /// passed in place of constructing the enum case. Note: pipeline updates are only supported
-    /// in MongoDB 4.2+. See the official MongoDB
+    /// passed in place of constructing the enum case. See the official MongoDB
     /// [documentation](https://www.mongodb.com/docs/manual/reference/command/update/#behavior) for more information on specifying updates.
     ///
     /// `await` will return d[`Result<UpdateResult>`].
@@ -41,8 +40,7 @@ where
     /// Updates up to one document matching `query` in the collection.
     ///
     /// Both `Document` and `Vec<Document>` implement `Into<UpdateModifications>`, so either can be
-    /// passed in place of constructing the enum case. Note: pipeline updates are only supported
-    /// in MongoDB 4.2+. See the official MongoDB
+    /// passed in place of constructing the enum case. See the official MongoDB
     /// [documentation](https://www.mongodb.com/docs/manual/reference/command/update/#behavior) for more information on specifying updates.
     ///
     /// This operation will retry once upon failure if the connection and encountered error support
@@ -73,8 +71,7 @@ where
     /// Updates all documents matching `query` in the collection.
     ///
     /// Both `Document` and `Vec<Document>` implement `Into<UpdateModifications>`, so either can be
-    /// passed in place of constructing the enum case. Note: pipeline updates are only supported
-    /// in MongoDB 4.2+. See the official MongoDB
+    /// passed in place of constructing the enum case. See the official MongoDB
     /// [documentation](https://www.mongodb.com/docs/manual/reference/command/update/#behavior) for more information on specifying updates.
     ///
     /// [`run`](Update::run) will return d[`Result<UpdateResult>`].
@@ -87,8 +84,7 @@ where
     /// Updates up to one document matching `query` in the collection.
     ///
     /// Both `Document` and `Vec<Document>` implement `Into<UpdateModifications>`, so either can be
-    /// passed in place of constructing the enum case. Note: pipeline updates are only supported
-    /// in MongoDB 4.2+. See the official MongoDB
+    /// passed in place of constructing the enum case. See the official MongoDB
     /// [documentation](https://www.mongodb.com/docs/manual/reference/command/update/#behavior) for more information on specifying updates.
     ///
     /// This operation will retry once upon failure if the connection and encountered error support

src/action/watch.rs

@@ -33,8 +33,7 @@ use crate::{
 impl Client {
     /// Starts a new [`ChangeStream`] that receives events for all changes in the cluster. The
     /// stream does not observe changes from system collections or the "config", "local" or
-    /// "admin" databases. Note that this method (`watch` on a cluster) is only supported in
-    /// MongoDB 4.0 or greater.
+    /// "admin" databases.
     ///
     /// See the documentation [here](https://www.mongodb.com/docs/manual/changeStreams/) on change
     /// streams.
@@ -121,8 +120,7 @@ where
 impl crate::sync::Client {
     /// Starts a new [`ChangeStream`] that receives events for all changes in the cluster. The
     /// stream does not observe changes from system collections or the "config", "local" or
-    /// "admin" databases. Note that this method (`watch` on a cluster) is only supported in
-    /// MongoDB 4.0 or greater.
+    /// "admin" databases.
     ///
     /// See the documentation [here](https://www.mongodb.com/docs/manual/changeStreams/) on change
     /// streams.

src/change_stream/options.rs

@@ -51,8 +51,6 @@ pub struct ChangeStreamOptions {
     /// the token. This will allow users to watch collections that have been dropped and
     /// recreated or newly renamed collections without missing any notifications.
     ///
-    /// This feature is only available on MongoDB 4.2+.
-    ///
     /// See the documentation [here](https://www.mongodb.com/docs/master/changeStreams/#change-stream-start-after) for more
     /// information.
     pub start_after: Option<ResumeToken>,

src/client/session.rs

@@ -45,8 +45,7 @@ pub(crate) static SESSIONS_UNSUPPORTED_COMMANDS: Lazy<HashSet<&'static str>> = L
 /// collections atomically. For more information about when and how to use transactions in MongoDB,
 /// see the [manual](https://www.mongodb.com/docs/manual/core/transactions/).
 ///
-/// Replica set transactions are supported on MongoDB 4.0+. Sharded transactions are supported on
-/// MongoDDB 4.2+. Transactions are associated with a `ClientSession`. To begin a transaction, call
+/// Transactions are associated with a `ClientSession`. To begin a transaction, call
 /// [`ClientSession::start_transaction`] on a `ClientSession`. The `ClientSession` must be passed to
 /// operations to be executed within the transaction.
 ///

src/cmap/conn.rs

@@ -44,8 +44,8 @@ pub struct ConnectionInfo {
     /// A driver-generated identifier that uniquely identifies the connection.
     pub id: u32,
 
-    /// A server-generated identifier that uniquely identifies the connection. Available on server
-    /// versions 4.2+. This may be used to correlate driver connections with server logs.
+    /// A server-generated identifier that uniquely identifies the connection. This may be used to
+    /// correlate driver connections with server logs.
     pub server_id: Option<i64>,
 
     /// The address that the connection is connected to.
@@ -64,7 +64,7 @@ pub(crate) struct Connection {
     /// Driver-generated ID for the connection.
     pub(crate) id: u32,
 
-    /// The server-side ID for this connection. Only set on server versions 4.2+.
+    /// The server-side ID for this connection.
     pub(crate) server_id: Option<i64>,
 
     /// The address of the server to which this connection connects.

src/cmap/test/integration.rs

@@ -17,8 +17,6 @@ use crate::{
     sdam::TopologyUpdater,
     selection_criteria::ReadPreference,
     test::{
-        block_connection_supported,
-        fail_command_supported,
         get_client_options,
         log_uncaptured,
         topology_is_load_balanced,
@@ -86,13 +84,6 @@ async fn acquire_connection_and_send_command() {
 
 #[tokio::test]
 async fn concurrent_connections() {
-    if !block_connection_supported().await {
-        log_uncaptured(
-            "skipping concurrent_connections test due to server not supporting block connection",
-        );
-        return;
-    }
-
     let mut options = get_client_options().await.clone();
     if options.load_balanced.unwrap_or(false) {
         log_uncaptured("skipping concurrent_connections test due to load-balanced topology");
@@ -166,22 +157,13 @@ async fn concurrent_connections() {
 }
 
 #[tokio::test(flavor = "multi_thread")]
-#[function_name::named]
-
 async fn connection_error_during_establishment() {
     if topology_is_load_balanced().await {
         log_uncaptured(
             "skipping connection_error_during_establishment test due to load-balanced topology",
         );
         return;
     }
-    if !fail_command_supported().await {
-        log_uncaptured(format!(
-            "skipping {} due to failCommand not being supported",
-            function_name!()
-        ));
-        return;
-    }
 
     let mut client_options = get_client_options().await.clone();
     client_options.heartbeat_freq = Duration::from_secs(300).into(); // high so that monitors dont trip failpoint
@@ -227,17 +209,7 @@ async fn connection_error_during_establishment() {
 }
 
 #[tokio::test(flavor = "multi_thread")]
-#[function_name::named]
-
 async fn connection_error_during_operation() {
-    if !fail_command_supported().await {
-        log_uncaptured(format!(
-            "skipping {} due to failCommand not being supported",
-            function_name!()
-        ));
-        return;
-    }
-
     let mut options = get_client_options().await.clone();
     let buffer = EventBuffer::<CmapEvent>::new();
     options.cmap_event_handler = Some(buffer.handler());

src/coll/options.rs

@@ -177,7 +177,6 @@ pub enum UpdateModifications {
     Document(Document),
 
     /// An aggregation pipeline.
-    /// Only available in MongoDB 4.2+.
     Pipeline(Vec<Document>),
 }
 
@@ -223,7 +222,7 @@ pub struct UpdateOptions {
 
     /// A document or string that specifies the index to use to support the query predicate.
     ///
-    /// Only available in MongoDB 4.2+. See the official MongoDB
+    /// See the official MongoDB
     /// [documentation](https://www.mongodb.com/docs/manual/reference/command/update/#ex-update-command-hint) for examples.
     pub hint: Option<Hint>,
 
@@ -290,7 +289,7 @@ pub struct ReplaceOptions {
 
     /// A document or string that specifies the index to use to support the query predicate.
     ///
-    /// Only available in MongoDB 4.2+. See the official MongoDB
+    /// See the official MongoDB
     /// [documentation](https://www.mongodb.com/docs/manual/reference/command/update/#ex-update-command-hint) for examples.
     pub hint: Option<Hint>,
 

src/concern/test.rs

@@ -134,11 +134,6 @@ async fn unacknowledged_write_concern_rejected() {
 #[tokio::test]
 #[function_name::named]
 async fn snapshot_read_concern() {
-    // snapshot read concern was introduced in 4.0
-    if server_version_lt(4, 0).await {
-        return;
-    }
-
     let client = Client::for_test().monitor_events().await;
 
     let coll = client

src/event/sdam.rs

@@ -125,9 +125,9 @@ pub struct ServerHeartbeatStartedEvent {
     /// The driver-generated ID for the connection used for the heartbeat.
     pub driver_connection_id: u32,
 
-    /// The server-generated ID for the connection used for the heartbeat. This value is only
-    /// present on server versions 4.2+. If this event corresponds to the first heartbeat on a
-    /// new monitoring connection, this value will not be present.
+    /// The server-generated ID for the connection used for the heartbeat. If this event
+    /// corresponds to the first heartbeat on a new monitoring connection, this value will not
+    /// be present.
     pub server_connection_id: Option<i64>,
 }
 
@@ -151,8 +151,7 @@ pub struct ServerHeartbeatSucceededEvent {
     /// The driver-generated ID for the connection used for the heartbeat.
     pub driver_connection_id: u32,
 
-    /// The server-generated ID for the connection used for the heartbeat. This value is only
-    /// present for server versions 4.2+.
+    /// The server-generated ID for the connection used for the heartbeat.
     pub server_connection_id: Option<i64>,
 }
 
@@ -177,9 +176,9 @@ pub struct ServerHeartbeatFailedEvent {
     /// The driver-generated ID for the connection used for the heartbeat.
     pub driver_connection_id: u32,
 
-    /// The server-generated ID for the connection used for the heartbeat. This value is only
-    /// present on server versions 4.2+. If this event corresponds to the first heartbeat on a
-    /// new monitoring connection, this value will not be present.
+    /// The server-generated ID for the connection used for the heartbeat. If this event
+    /// corresponds to the first heartbeat on a new monitoring connection, this value will not
+    /// be present.
     pub server_connection_id: Option<i64>,
 }
 

src/operation.rs

@@ -75,7 +75,6 @@ pub(crate) use raw_output::RawOutput;
 pub(crate) use search_index::{CreateSearchIndexes, DropSearchIndex, UpdateSearchIndex};
 pub(crate) use update::{Update, UpdateOrReplace};
 
-const SERVER_4_2_0_WIRE_VERSION: i32 = 8;
 const SERVER_4_4_0_WIRE_VERSION: i32 = 9;
 const SERVER_5_0_0_WIRE_VERSION: i32 = 13;
 const SERVER_8_0_0_WIRE_VERSION: i32 = 25;

src/operation/aggregate.rs

@@ -17,7 +17,6 @@ use super::{
     ExecutionContext,
     OperationWithDefaults,
     WriteConcernOnlyBody,
-    SERVER_4_2_0_WIRE_VERSION,
     SERVER_4_4_0_WIRE_VERSION,
 };
 
@@ -115,10 +114,9 @@ impl OperationWithDefaults for Aggregate {
             .and_then(|opts| opts.selection_criteria.as_ref())
     }
 
-    fn supports_read_concern(&self, description: &StreamDescription) -> bool {
-        // for aggregates that write, read concern is only supported in MongoDB 4.2+.
-        !self.is_out_or_merge()
-            || description.max_wire_version.unwrap_or(0) >= SERVER_4_2_0_WIRE_VERSION
+    fn supports_read_concern(&self, _description: &StreamDescription) -> bool {
+        // for aggregates that write, read concern is supported in MongoDB 4.2+.
+        true
     }
 
     fn write_concern(&self) -> Option<&WriteConcern> {