Added feature test and docs

Author: GumpacG

CHANGELOG.asciidoc

@@ -22,6 +22,11 @@ under the License.
 
 image::https://raw.githubusercontent.com/apache/tinkerpop/master/docs/static/images/gremlin-zamfir.png[width=185]
 
+[[release-3-7-7]]
+=== TinkerPop 3.7.7 (NOT OFFICIALLY RELEASED YET)
+
+* Fixed conjoin has incorrect null handling.
+
 [[release-3-7-6]]
 === TinkerPop 3.7.6 (Release Date: April 1, 2026)
 

docs/src/upgrade/release-3.7.x.asciidoc

@@ -23,6 +23,42 @@ image::gremlin-zamfir.png[width=185]
 
 *Gremfir Master of the Pan Flute*
 
+== TinkerPop 3.7.7
+
+*Release Date: NOT OFFICIALLY RELEASED YET*
+
+Please see the link:https://github.com/apache/tinkerpop/blob/3.7.7/CHANGELOG.asciidoc#release-3-7-7[changelog] for a
+complete list of all the modifications that are part of this release.
+
+=== Upgrading for Users
+
+==== conjoin() Step Null Handling
+
+The `conjoin()` step previously returned `null` when elements in the incoming list are `null`. This behavior has
+been changed so that `conjoin()` now returns an empty string (`""`) in that case.
+
+[source,groovy]
+----
+// 3.7.6
+gremlin> g.inject([null]).conjoin("-")
+==>null
+gremlin> g.inject([null, null]).conjoin("-")
+==>null
+
+// 3.7.7
+gremlin> g.inject([null]).conjoin("+")
+==>
+gremlin> g.inject([null, null]).conjoin("+")
+==>
+----
+
+Code that checks the result of `conjoin()` for lists that include `null` elements should be updated to check for
+an empty string instead.
+
+See: link:https://issues.apache.org/jira/browse/TINKERPOP-3225[TINKERPOP-3225]
+
+
+
 == TinkerPop 3.7.6
 
 *Release Date: April 1, 2026*
@@ -122,13 +158,13 @@ opens a session, submits one or more `addV()` operations, commits, and closes th
 The benchmark varies the following parameters:
 
 * *Concurrent clients* (`threads`): The number of threads issuing transactions simultaneously. A value of 1 means
-  transactions are executed sequentially by a single client. Higher values simulate multiple application threads or
-  service instances issuing transactions concurrently against the same server.
+transactions are executed sequentially by a single client. Higher values simulate multiple application threads or
+service instances issuing transactions concurrently against the same server.
 * *Connection pool size* (`pool`): The number of WebSocket connections maintained in the pool when
-  `reuseConnectionsForSessions` is enabled. When reuse is disabled, each session creates its own dedicated connection
-  and this parameter does not apply (shown as `n/a`).
+`reuseConnectionsForSessions` is enabled. When reuse is disabled, each session creates its own dedicated connection
+and this parameter does not apply (shown as `n/a`).
 * *Transaction weight* (`weight`): "light" transactions perform a single `addV()` plus commit. "heavy" transactions
-  perform ten `addV()` operations plus commit, simulating a more substantial unit of work per transaction.
+perform ten `addV()` operations plus commit, simulating a more substantial unit of work per transaction.
 
 Tests were conducted both locally (client and server on the same machine) and remotely (client on the US west coast,
 server on the US east coast) to isolate the effect of network latency on connection setup overhead. Each scenario
@@ -1001,7 +1037,7 @@ For 3.7:
 [source,json]
 ----
 {"id":1,"label":"person","properties":{"name":[{"id":0,"label":"name","value":"marko","key":"name"}],"age":[{"id":1,"label":"age","value":29,"key":"age"}]}}
----- 
+----
 
 ===== Enabling the previous behavior
 

gremlin-dotnet/test/Gremlin.Net.IntegrationTest/Gherkin/Gremlin.cs

@@ -633,6 +633,8 @@ private static IDictionary<string, List<Func<GraphTraversalSource, IDictionary<s
                {"g_V_out_out_path_byXnameX_conjoinXX", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.V().Out().Out().Path().By("name").Conjoin("")}}, 
                {"g_injectXa_null_bX_conjoinXxyzX", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.Inject(p["xx1"]).Conjoin("xyz")}}, 
                {"g_injectX3_threeX_conjoinX_X", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.Inject(p["xx1"]).Conjoin(";")}}, 
+               {"g_injectXnull_a_null_bX_fold_conjoinXplusX", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.Inject(p["xx1"]).Conjoin("+")}}, 
+               {"g_injectXnull_nullX_conjoinXplusX", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.Inject(p["xx1"]).Conjoin("+")}}, 
                {"g_V_connectedComponent_hasXcomponentX", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.V().ConnectedComponent().Has("gremlin.connectedComponentVertexProgram.component")}}, 
                {"g_V_dedup_connectedComponent_hasXcomponentX", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.V().Dedup().ConnectedComponent().Has("gremlin.connectedComponentVertexProgram.component")}}, 
                {"g_V_hasLabelXsoftwareX_connectedComponent_project_byXnameX_byXcomponentX", new List<Func<GraphTraversalSource, IDictionary<string, object>, ITraversal>> {(g,p) =>g.V().HasLabel("software").ConnectedComponent().Project<object>("name","component").By("name").By("gremlin.connectedComponentVertexProgram.component")}}, 

gremlin-go/driver/cucumber/gremlin.go

@@ -604,6 +604,8 @@ var translationMap = map[string][]func(g *gremlingo.GraphTraversalSource, p map[
     "g_V_out_out_path_byXnameX_conjoinXX": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.V().Out().Out().Path().By("name").Conjoin("")}}, 
     "g_injectXa_null_bX_conjoinXxyzX": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.Inject(p["xx1"]).Conjoin("xyz")}}, 
     "g_injectX3_threeX_conjoinX_X": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.Inject(p["xx1"]).Conjoin(";")}}, 
+    "g_injectXnull_a_null_bX_fold_conjoinXplusX": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.Inject(p["xx1"]).Conjoin("+")}}, 
+    "g_injectXnull_nullX_conjoinXplusX": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.Inject(p["xx1"]).Conjoin("+")}}, 
     "g_V_connectedComponent_hasXcomponentX": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.V().ConnectedComponent().Has("gremlin.connectedComponentVertexProgram.component")}}, 
     "g_V_dedup_connectedComponent_hasXcomponentX": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.V().Dedup().ConnectedComponent().Has("gremlin.connectedComponentVertexProgram.component")}}, 
     "g_V_hasLabelXsoftwareX_connectedComponent_project_byXnameX_byXcomponentX": {func(g *gremlingo.GraphTraversalSource, p map[string]interface{}) *gremlingo.GraphTraversal {return g.V().HasLabel("software").ConnectedComponent().Project("name", "component").By("name").By("gremlin.connectedComponentVertexProgram.component")}}, 

gremlin-javascript/src/main/javascript/gremlin-javascript/test/cucumber/gremlin.js

@@ -606,6 +606,8 @@
     'g_V_out_out_path_byXnameX_conjoinXX': [(lambda g:g.V().out().out().path().by('name').conjoin(''))], 
     'g_injectXa_null_bX_conjoinXxyzX': [(lambda g, xx1=None:g.inject(xx1).conjoin('xyz'))], 
     'g_injectX3_threeX_conjoinX_X': [(lambda g, xx1=None:g.inject(xx1).conjoin(';'))], 
+    'g_injectXnull_a_null_bX_fold_conjoinXplusX': [(lambda g, xx1=None:g.inject(xx1).conjoin('+'))], 
+    'g_injectXnull_nullX_conjoinXplusX': [(lambda g, xx1=None:g.inject(xx1).conjoin('+'))], 
     'g_V_connectedComponent_hasXcomponentX': [(lambda g:g.V().connected_component().has('gremlin.connectedComponentVertexProgram.component'))], 
     'g_V_dedup_connectedComponent_hasXcomponentX': [(lambda g:g.V().dedup().connected_component().has('gremlin.connectedComponentVertexProgram.component'))], 
     'g_V_hasLabelXsoftwareX_connectedComponent_project_byXnameX_byXcomponentX': [(lambda g:g.V().has_label('software').connected_component().project('name','component').by('name').by('gremlin.connectedComponentVertexProgram.component'))], 

gremlin-python/src/main/python/tests/feature/gremlin.py

@@ -153,3 +153,29 @@ Feature: Step - conjoin()
     Then the result should be unordered
       | result |
       | 3;three |
+
+  @GraphComputerVerificationInjectionNotSupported
+  Scenario: g_injectXnull_a_null_bX_fold_conjoinXplusX
+    Given the empty graph
+    And using the parameter xx1 defined as "l[null,a,null,b]"
+    And the traversal of
+      """
+      g.inject(xx1).conjoin("+")
+      """
+    When iterated to list
+    Then the result should be unordered
+      | result |
+      | str[a+b] |
+
+  @GraphComputerVerificationInjectionNotSupported
+  Scenario: g_injectXnull_nullX_conjoinXplusX
+    Given the empty graph
+    And using the parameter xx1 defined as "l[null,null]"
+    And the traversal of
+      """
+      g.inject(xx1).conjoin("+")
+      """
+    When iterated to list
+    Then the result should be unordered
+      | result |
+      | str[] |