PHPC-1761: Snapshot Reads (#1243)

* Bump libmongoc to 1.19-dev

* PHPC-1890: Constant for ReadConcern snapshot level

* Move Manager::startSession() error test and delete obsolete test

The deleted error test was redundant. It was originally created in ca4c52e to work around changes in PHP 8, but 60febd0 subsequently reintroduced a portable version of the test case.

Also adds missing SKIPIF to startSession test.

* PHPC-1889: Session snapshot option

* PHPC-1875: Session with snapshot=true cannot perform writes

* PHPC-1876: Session with snapshot=true requires MongoDB 5.0+

Author: jmikola

config.m4

@@ -387,7 +387,7 @@ if test "$PHP_MONGODB" != "no"; then
     PHP_MONGODB_JSONSL_SOURCES="jsonsl.c"
 
     dnl Generated with: find src/libmongoc/src/libmongoc/src/mongoc -name '*.c' -print0 | cut -sz -d / -f 7- | sort -dz | tr '\000' ' '
-    PHP_MONGODB_MONGOC_SOURCES="mongoc-aggregate.c mongoc-apm.c mongoc-array.c mongoc-async.c mongoc-async-cmd.c mongoc-buffer.c mongoc-bulk-operation.c mongoc-change-stream.c mongoc-client.c mongoc-client-pool.c mongoc-client-session.c mongoc-client-side-encryption.c mongoc-cluster-aws.c mongoc-cluster.c mongoc-cluster-cyrus.c mongoc-cluster-sasl.c mongoc-cluster-sspi.c mongoc-cmd.c mongoc-collection.c mongoc-compression.c mongoc-counters.c mongoc-crypt.c mongoc-crypto.c mongoc-crypto-cng.c mongoc-crypto-common-crypto.c mongoc-crypto-openssl.c mongoc-cursor-array.c mongoc-cursor.c mongoc-cursor-change-stream.c mongoc-cursor-cmd.c mongoc-cursor-cmd-deprecated.c mongoc-cursor-find.c mongoc-cursor-find-cmd.c mongoc-cursor-find-opquery.c mongoc-cursor-legacy.c mongoc-cyrus.c mongoc-database.c mongoc-error.c mongoc-find-and-modify.c mongoc-gridfs-bucket.c mongoc-gridfs-bucket-file.c mongoc-gridfs.c mongoc-gridfs-file.c mongoc-gridfs-file-list.c mongoc-gridfs-file-page.c mongoc-handshake.c mongoc-host-list.c mongoc-http.c mongoc-index.c mongoc-init.c mongoc-interrupt.c mongoc-libressl.c mongoc-linux-distro-scanner.c mongoc-list.c mongoc-log.c mongoc-matcher.c mongoc-matcher-op.c mongoc-memcmp.c mongoc-ocsp-cache.c mongoc-openssl.c mongoc-optional.c mongoc-opts.c mongoc-opts-helpers.c mongoc-queue.c mongoc-rand-cng.c mongoc-rand-common-crypto.c mongoc-rand-openssl.c mongoc-read-concern.c mongoc-read-prefs.c mongoc-rpc.c mongoc-sasl.c mongoc-scram.c mongoc-secure-channel.c mongoc-secure-transport.c mongoc-server-api.c mongoc-server-description.c mongoc-server-monitor.c mongoc-server-stream.c mongoc-set.c mongoc-socket.c mongoc-ssl.c mongoc-sspi.c mongoc-stream-buffered.c mongoc-stream.c mongoc-stream-file.c mongoc-stream-gridfs.c mongoc-stream-gridfs-download.c mongoc-stream-gridfs-upload.c mongoc-stream-socket.c mongoc-stream-tls.c mongoc-stream-tls-libressl.c mongoc-stream-tls-openssl-bio.c mongoc-stream-tls-openssl.c mongoc-stream-tls-secure-channel.c mongoc-stream-tls-secure-transport.c mongoc-timeout.c mongoc-topology-background-monitoring.c mongoc-topology.c mongoc-topology-description-apm.c mongoc-topology-description.c mongoc-topology-scanner.c mongoc-uri.c mongoc-util.c mongoc-version-functions.c mongoc-write-command.c mongoc-write-command-legacy.c mongoc-write-concern.c"
+    PHP_MONGODB_MONGOC_SOURCES="mongoc-aggregate.c mongoc-apm.c mongoc-array.c mongoc-async.c mongoc-async-cmd.c mongoc-buffer.c mongoc-bulk-operation.c mongoc-change-stream.c mongoc-client.c mongoc-client-pool.c mongoc-client-session.c mongoc-client-side-encryption.c mongoc-cluster-aws.c mongoc-cluster.c mongoc-cluster-cyrus.c mongoc-cluster-sasl.c mongoc-cluster-sspi.c mongoc-cmd.c mongoc-collection.c mongoc-compression.c mongoc-counters.c mongoc-crypt.c mongoc-crypto.c mongoc-crypto-cng.c mongoc-crypto-common-crypto.c mongoc-crypto-openssl.c mongoc-cursor-array.c mongoc-cursor.c mongoc-cursor-change-stream.c mongoc-cursor-cmd.c mongoc-cursor-cmd-deprecated.c mongoc-cursor-find.c mongoc-cursor-find-cmd.c mongoc-cursor-find-opquery.c mongoc-cursor-legacy.c mongoc-cyrus.c mongoc-database.c mongoc-error.c mongoc-find-and-modify.c mongoc-generation-map.c mongoc-gridfs-bucket.c mongoc-gridfs-bucket-file.c mongoc-gridfs.c mongoc-gridfs-file.c mongoc-gridfs-file-list.c mongoc-gridfs-file-page.c mongoc-handshake.c mongoc-host-list.c mongoc-http.c mongoc-index.c mongoc-init.c mongoc-interrupt.c mongoc-libressl.c mongoc-linux-distro-scanner.c mongoc-list.c mongoc-log.c mongoc-matcher.c mongoc-matcher-op.c mongoc-memcmp.c mongoc-ocsp-cache.c mongoc-openssl.c mongoc-optional.c mongoc-opts.c mongoc-opts-helpers.c mongoc-queue.c mongoc-rand-cng.c mongoc-rand-common-crypto.c mongoc-rand-openssl.c mongoc-read-concern.c mongoc-read-prefs.c mongoc-rpc.c mongoc-sasl.c mongoc-scram.c mongoc-secure-channel.c mongoc-secure-transport.c mongoc-server-api.c mongoc-server-description.c mongoc-server-monitor.c mongoc-server-stream.c mongoc-set.c mongoc-socket.c mongoc-ssl.c mongoc-sspi.c mongoc-stream-buffered.c mongoc-stream.c mongoc-stream-file.c mongoc-stream-gridfs.c mongoc-stream-gridfs-download.c mongoc-stream-gridfs-upload.c mongoc-stream-socket.c mongoc-stream-tls.c mongoc-stream-tls-libressl.c mongoc-stream-tls-openssl-bio.c mongoc-stream-tls-openssl.c mongoc-stream-tls-secure-channel.c mongoc-stream-tls-secure-transport.c mongoc-timeout.c mongoc-topology-background-monitoring.c mongoc-topology.c mongoc-topology-description-apm.c mongoc-topology-description.c mongoc-topology-scanner.c mongoc-uri.c mongoc-util.c mongoc-version-functions.c mongoc-write-command.c mongoc-write-command-legacy.c mongoc-write-concern.c"
 
     dnl Generated with: find src/libmongoc/src/zlib-1.2.11 -maxdepth 1 -name '*.c' -print0 | cut -sz -d / -f 5- | sort -dz | tr '\000' ' '
     PHP_MONGODB_ZLIB_SOURCES="adler32.c compress.c crc32.c deflate.c gzclose.c gzlib.c gzread.c gzwrite.c infback.c inffast.c inflate.c inftrees.c trees.c uncompr.c zutil.c"

config.w32

@@ -115,7 +115,7 @@ if (PHP_MONGODB != "no") {
   var PHP_MONGODB_JSONSL_SOURCES="jsonsl.c";
 
   // Generated with: find src/libmongoc/src/libmongoc/src/mongoc -name '*.c' -print0 | cut -sz -d / -f 7- | sort -dz | tr '\000' ' '
-  var PHP_MONGODB_MONGOC_SOURCES="mongoc-aggregate.c mongoc-apm.c mongoc-array.c mongoc-async.c mongoc-async-cmd.c mongoc-buffer.c mongoc-bulk-operation.c mongoc-change-stream.c mongoc-client.c mongoc-client-pool.c mongoc-client-session.c mongoc-client-side-encryption.c mongoc-cluster-aws.c mongoc-cluster.c mongoc-cluster-cyrus.c mongoc-cluster-sasl.c mongoc-cluster-sspi.c mongoc-cmd.c mongoc-collection.c mongoc-compression.c mongoc-counters.c mongoc-crypt.c mongoc-crypto.c mongoc-crypto-cng.c mongoc-crypto-common-crypto.c mongoc-crypto-openssl.c mongoc-cursor-array.c mongoc-cursor.c mongoc-cursor-change-stream.c mongoc-cursor-cmd.c mongoc-cursor-cmd-deprecated.c mongoc-cursor-find.c mongoc-cursor-find-cmd.c mongoc-cursor-find-opquery.c mongoc-cursor-legacy.c mongoc-cyrus.c mongoc-database.c mongoc-error.c mongoc-find-and-modify.c mongoc-gridfs-bucket.c mongoc-gridfs-bucket-file.c mongoc-gridfs.c mongoc-gridfs-file.c mongoc-gridfs-file-list.c mongoc-gridfs-file-page.c mongoc-handshake.c mongoc-host-list.c mongoc-http.c mongoc-index.c mongoc-init.c mongoc-interrupt.c mongoc-libressl.c mongoc-linux-distro-scanner.c mongoc-list.c mongoc-log.c mongoc-matcher.c mongoc-matcher-op.c mongoc-memcmp.c mongoc-ocsp-cache.c mongoc-openssl.c mongoc-optional.c mongoc-opts.c mongoc-opts-helpers.c mongoc-queue.c mongoc-rand-cng.c mongoc-rand-common-crypto.c mongoc-rand-openssl.c mongoc-read-concern.c mongoc-read-prefs.c mongoc-rpc.c mongoc-sasl.c mongoc-scram.c mongoc-secure-channel.c mongoc-secure-transport.c mongoc-server-api.c mongoc-server-description.c mongoc-server-monitor.c mongoc-server-stream.c mongoc-set.c mongoc-socket.c mongoc-ssl.c mongoc-sspi.c mongoc-stream-buffered.c mongoc-stream.c mongoc-stream-file.c mongoc-stream-gridfs.c mongoc-stream-gridfs-download.c mongoc-stream-gridfs-upload.c mongoc-stream-socket.c mongoc-stream-tls.c mongoc-stream-tls-libressl.c mongoc-stream-tls-openssl-bio.c mongoc-stream-tls-openssl.c mongoc-stream-tls-secure-channel.c mongoc-stream-tls-secure-transport.c mongoc-timeout.c mongoc-topology-background-monitoring.c mongoc-topology.c mongoc-topology-description-apm.c mongoc-topology-description.c mongoc-topology-scanner.c mongoc-uri.c mongoc-util.c mongoc-version-functions.c mongoc-write-command.c mongoc-write-command-legacy.c mongoc-write-concern.c";
+  var PHP_MONGODB_MONGOC_SOURCES="mongoc-aggregate.c mongoc-apm.c mongoc-array.c mongoc-async.c mongoc-async-cmd.c mongoc-buffer.c mongoc-bulk-operation.c mongoc-change-stream.c mongoc-client.c mongoc-client-pool.c mongoc-client-session.c mongoc-client-side-encryption.c mongoc-cluster-aws.c mongoc-cluster.c mongoc-cluster-cyrus.c mongoc-cluster-sasl.c mongoc-cluster-sspi.c mongoc-cmd.c mongoc-collection.c mongoc-compression.c mongoc-counters.c mongoc-crypt.c mongoc-crypto.c mongoc-crypto-cng.c mongoc-crypto-common-crypto.c mongoc-crypto-openssl.c mongoc-cursor-array.c mongoc-cursor.c mongoc-cursor-change-stream.c mongoc-cursor-cmd.c mongoc-cursor-cmd-deprecated.c mongoc-cursor-find.c mongoc-cursor-find-cmd.c mongoc-cursor-find-opquery.c mongoc-cursor-legacy.c mongoc-cyrus.c mongoc-database.c mongoc-error.c mongoc-find-and-modify.c mongoc-generation-map.c mongoc-gridfs-bucket.c mongoc-gridfs-bucket-file.c mongoc-gridfs.c mongoc-gridfs-file.c mongoc-gridfs-file-list.c mongoc-gridfs-file-page.c mongoc-handshake.c mongoc-host-list.c mongoc-http.c mongoc-index.c mongoc-init.c mongoc-interrupt.c mongoc-libressl.c mongoc-linux-distro-scanner.c mongoc-list.c mongoc-log.c mongoc-matcher.c mongoc-matcher-op.c mongoc-memcmp.c mongoc-ocsp-cache.c mongoc-openssl.c mongoc-optional.c mongoc-opts.c mongoc-opts-helpers.c mongoc-queue.c mongoc-rand-cng.c mongoc-rand-common-crypto.c mongoc-rand-openssl.c mongoc-read-concern.c mongoc-read-prefs.c mongoc-rpc.c mongoc-sasl.c mongoc-scram.c mongoc-secure-channel.c mongoc-secure-transport.c mongoc-server-api.c mongoc-server-description.c mongoc-server-monitor.c mongoc-server-stream.c mongoc-set.c mongoc-socket.c mongoc-ssl.c mongoc-sspi.c mongoc-stream-buffered.c mongoc-stream.c mongoc-stream-file.c mongoc-stream-gridfs.c mongoc-stream-gridfs-download.c mongoc-stream-gridfs-upload.c mongoc-stream-socket.c mongoc-stream-tls.c mongoc-stream-tls-libressl.c mongoc-stream-tls-openssl-bio.c mongoc-stream-tls-openssl.c mongoc-stream-tls-secure-channel.c mongoc-stream-tls-secure-transport.c mongoc-timeout.c mongoc-topology-background-monitoring.c mongoc-topology.c mongoc-topology-description-apm.c mongoc-topology-description.c mongoc-topology-scanner.c mongoc-uri.c mongoc-util.c mongoc-version-functions.c mongoc-write-command.c mongoc-write-command-legacy.c mongoc-write-concern.c";
 
   EXTENSION("mongodb", "php_phongo.c phongo_compat.c", null, PHP_MONGODB_CFLAGS);
   MONGODB_ADD_SOURCES("/src", "bson.c bson-encode.c phongo_apm.c");

src/LIBMONGOC_VERSION_CURRENT

@@ -1 +1 @@
-1.18.0
+1.11.1-20210804+git230369cd07

src/MongoDB/Manager.c

@@ -805,6 +805,18 @@ static PHP_METHOD(Manager, startSession)
 		}
 	}
 
+	if (options && php_array_existsc(options, "snapshot")) {
+		if (!cs_opts) {
+			cs_opts = mongoc_session_opts_new();
+		}
+		mongoc_session_opts_set_snapshot(cs_opts, php_array_fetchc_bool(options, "snapshot"));
+	}
+
+	if (cs_opts && mongoc_session_opts_get_causal_consistency(cs_opts) && mongoc_session_opts_get_snapshot(cs_opts)) {
+		phongo_throw_exception(PHONGO_ERROR_INVALID_ARGUMENT, "Only one of \"causalConsistency\" and \"snapshot\" can be enabled");
+		goto cleanup;
+	}
+
 	/* If the Manager was created in a different process, reset the client so
 	 * that its session pool is cleared. This will ensure that we do not re-use
 	 * a server session (i.e. LSID) created by a parent process. */

src/MongoDB/ReadConcern.c

@@ -370,6 +370,7 @@ void php_phongo_readconcern_init_ce(INIT_FUNC_ARGS) /* {{{ */
 	zend_declare_class_constant_stringl(php_phongo_readconcern_ce, ZEND_STRL("MAJORITY"), ZEND_STRL(MONGOC_READ_CONCERN_LEVEL_MAJORITY));
 	zend_declare_class_constant_stringl(php_phongo_readconcern_ce, ZEND_STRL("LINEARIZABLE"), ZEND_STRL(MONGOC_READ_CONCERN_LEVEL_LINEARIZABLE));
 	zend_declare_class_constant_stringl(php_phongo_readconcern_ce, ZEND_STRL("AVAILABLE"), ZEND_STRL(MONGOC_READ_CONCERN_LEVEL_AVAILABLE));
+	zend_declare_class_constant_stringl(php_phongo_readconcern_ce, ZEND_STRL("SNAPSHOT"), ZEND_STRL(MONGOC_READ_CONCERN_LEVEL_SNAPSHOT));
 } /* }}} */
 
 /*

src/MongoDB/Session.c

@@ -740,8 +740,10 @@ static HashTable* php_phongo_session_get_debug_info(phongo_compat_object_handler
 	if (intern->client_session) {
 		const mongoc_session_opt_t* cs_opts = mongoc_client_session_get_opts(intern->client_session);
 		ADD_ASSOC_BOOL_EX(&retval, "causalConsistency", mongoc_session_opts_get_causal_consistency(cs_opts));
+		ADD_ASSOC_BOOL_EX(&retval, "snapshot", mongoc_session_opts_get_snapshot(cs_opts));
 	} else {
 		ADD_ASSOC_NULL_EX(&retval, "causalConsistency");
+		ADD_ASSOC_NULL_EX(&retval, "snapshot");
 	}
 
 	if (intern->client_session) {

src/libmongoc

@@ -1,5 +1,10 @@
 --TEST--
-MongoDB\Driver\Session with wrong defaultTransactionOptions
+MongoDB\Driver\Manager::startSession() with wrong defaultTransactionOptions
+--SKIPIF--
+<?php require __DIR__ . "/../utils/basic-skipif.inc"; ?>
+<?php skip_if_not_libmongoc_crypto(); ?>
+<?php skip_if_not_live(); ?>
+<?php skip_if_server_version('<', '3.6'); ?>
 --FILE--
 <?php
 require_once __DIR__ . "/../utils/basic.inc";
@@ -40,7 +45,7 @@ foreach ($options as $txnOptions) {
         $manager->startSession([
             'defaultTransactionOptions' => $txnOptions
         ]);
-    }, 'MongoDB\Driver\Exception\InvalidArgumentException'), "\n";
+    }, MongoDB\Driver\Exception\InvalidArgumentException::class), "\n";
 }
 
 echo raises(function() use ($manager) {

tests/session/session_error-001.phpt renamed to tests/manager/manager-startSession_error-001.phpt

@@ -0,0 +1,30 @@
+--TEST--
+MongoDB\Driver\Manager::startSession() snapshot and causalConsistency cannot both be true
+--DESCRIPTION--
+Session spec prose test #1
+https://github.com/mongodb/specifications/blob/master/source/sessions/tests/README.rst#prose-tests
+--SKIPIF--
+<?php require __DIR__ . "/../utils/basic-skipif.inc"; ?>
+<?php skip_if_not_libmongoc_crypto(); ?>
+<?php skip_if_not_live(); ?>
+<?php skip_if_server_version('<', '3.6'); ?>
+--FILE--
+<?php
+require_once __DIR__ . "/../utils/basic.inc";
+
+$manager = create_test_manager();
+
+echo throws(function() use ($manager) {
+    $manager->startSession([
+        'causalConsistency' => true,
+        'snapshot' => true,
+    ]);
+}, MongoDB\Driver\Exception\InvalidArgumentException::class), "\n";
+
+?>
+===DONE===
+<?php exit(0); ?>
+--EXPECT--
+OK: Got MongoDB\Driver\Exception\InvalidArgumentException
+Only one of "causalConsistency" and "snapshot" can be enabled
+===DONE===

tests/manager/manager-startSession_error-002.phpt

@@ -11,6 +11,7 @@ $tests = [
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::LOCAL),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::MAJORITY),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::AVAILABLE),
+    new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::SNAPSHOT),
 ];
 
 foreach ($tests as $test) {
@@ -26,4 +27,5 @@ foreach ($tests as $test) {
 { "level" : "local" }
 { "level" : "majority" }
 { "level" : "available" }
+{ "level" : "snapshot" }
 ===DONE===

tests/readConcern/readconcern-bsonserialize-001.phpt

@@ -11,6 +11,7 @@ $tests = [
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::LOCAL),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::MAJORITY),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::AVAILABLE),
+    new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::SNAPSHOT),
 ];
 
 foreach ($tests as $test) {
@@ -39,4 +40,8 @@ object(stdClass)#%d (%d) {
   ["level"]=>
   string(9) "available"
 }
+object(stdClass)#%d (%d) {
+  ["level"]=>
+  string(8) "snapshot"
+}
 ===DONE===

tests/readConcern/readconcern-bsonserialize-002.phpt

@@ -7,6 +7,7 @@ var_dump(MongoDB\Driver\ReadConcern::LINEARIZABLE);
 var_dump(MongoDB\Driver\ReadConcern::LOCAL);
 var_dump(MongoDB\Driver\ReadConcern::MAJORITY);
 var_dump(MongoDB\Driver\ReadConcern::AVAILABLE);
+var_dump(MongoDB\Driver\ReadConcern::SNAPSHOT);
 
 ?>
 ===DONE===
@@ -16,4 +17,5 @@ string(12) "linearizable"
 string(5) "local"
 string(8) "majority"
 string(9) "available"
+string(8) "snapshot"
 ===DONE===

tests/readConcern/readconcern-constants.phpt

@@ -11,6 +11,7 @@ $tests = [
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::LOCAL),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::MAJORITY),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::AVAILABLE),
+    new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::SNAPSHOT),
 ];
 
 foreach ($tests as $test) {
@@ -39,4 +40,8 @@ object(MongoDB\Driver\ReadConcern)#%d (%d) {
   ["level"]=>
   string(9) "available"
 }
+object(MongoDB\Driver\ReadConcern)#%d (%d) {
+  ["level"]=>
+  string(8) "snapshot"
+}
 ===DONE===

tests/readConcern/readconcern-debug-001.phpt

@@ -11,6 +11,7 @@ $tests = [
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::LOCAL),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::MAJORITY),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::AVAILABLE),
+    new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::SNAPSHOT),
 ];
 
 foreach ($tests as $test) {
@@ -76,4 +77,15 @@ object(MongoDB\Driver\ReadConcern)#%d (%d) {
   string(9) "available"
 }
 
+object(MongoDB\Driver\ReadConcern)#%d (%d) {
+  ["level"]=>
+  string(8) "snapshot"
+}
+bool(true)
+C:26:"MongoDB\Driver\ReadConcern":33:{a:1:{s:5:"level";s:8:"snapshot";}}
+object(MongoDB\Driver\ReadConcern)#%d (%d) {
+  ["level"]=>
+  string(8) "snapshot"
+}
+
 ===DONE===

tests/readConcern/readconcern-serialization-001.phpt

@@ -8,6 +8,7 @@ $tests = [
     MongoDB\Driver\ReadConcern::LINEARIZABLE,
     MongoDB\Driver\ReadConcern::LOCAL,
     MongoDB\Driver\ReadConcern::MAJORITY,
+    MongoDB\Driver\ReadConcern::SNAPSHOT,
 ];
 
 foreach ($tests as $level) {
@@ -42,6 +43,10 @@ MongoDB\Driver\ReadConcern::__set_state(array(
 %w'level' => 'majority',
 ))
 
+MongoDB\Driver\ReadConcern::__set_state(array(
+%w'level' => 'snapshot',
+))
+
 MongoDB\Driver\ReadConcern::__set_state(array(
 ))
 

tests/readConcern/readconcern-set_state-001.phpt

@@ -11,6 +11,7 @@ $tests = [
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::LOCAL),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::MAJORITY),
     new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::AVAILABLE),
+    new MongoDB\Driver\ReadConcern(MongoDB\Driver\ReadConcern::SNAPSHOT),
 ];
 
 foreach ($tests as $test) {
@@ -35,4 +36,7 @@ MongoDB\Driver\ReadConcern::__set_state(array(
 MongoDB\Driver\ReadConcern::__set_state(array(
    'level' => 'available',
 ))
+MongoDB\Driver\ReadConcern::__set_state(array(
+   'level' => 'snapshot',
+))
 ===DONE===

tests/readConcern/readconcern-var_export-001.phpt

@@ -0,0 +1,34 @@
+--TEST--
+MongoDB\Driver\Session spec test: snapshot option is incompatible with writes
+--DESCRIPTION--
+PHPC-1875: Disable writes on snapshot sessions
+--SKIPIF--
+<?php require __DIR__ . "/../utils/basic-skipif.inc"; ?>
+<?php skip_if_not_libmongoc_crypto(); ?>
+<?php skip_if_not_live(); ?>
+<?php skip_if_server_version('<', '5.0'); ?>
+--FILE--
+<?php
+require_once __DIR__ . "/../utils/basic.inc";
+
+$manager = create_test_manager();
+$session = $manager->startSession(['snapshot' => true]);
+
+$bulk = new MongoDB\Driver\BulkWrite();
+$bulk->insert(['x' => 1]);
+
+try {
+    $manager->executeBulkWrite(NS, $bulk, ['session' => $session]);
+} catch (MongoDB\Driver\Exception\BulkWriteException $e) {
+    /* Note: we intentionally do not assert the server's error message for the
+     * client specifying a read concern on a write command. It is sufficient to
+     * assert that the error code is InvalidOptions(72). */
+    var_dump($e->getCode() === 72);
+}
+
+?>
+===DONE===
+<?php exit(0); ?>
+--EXPECT--
+bool(true)
+===DONE===