chore: app deduplication

DanielleMaywood · DanielleMaywood · commit d1da3a1cbd31 · 2025-06-18T12:06:04.000Z
diff --git a/agent/agentcontainers/api.go b/agent/agentcontainers/api.go
@@ -1139,7 +1139,7 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 			codersdk.DisplayAppPortForward:    true,
 		}
 
-		var apps []SubAgentApp
+		var appsWithPossibleDuplicates []SubAgentApp
 
 		if config, err := api.dccli.ReadConfig(ctx, dc.WorkspaceFolder, dc.ConfigPath,
 			[]string{
@@ -1165,7 +1165,7 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 					displayAppsMap[app] = enabled
 				}
 
-				apps = append(apps, customization.Apps...)
+				appsWithPossibleDuplicates = append(appsWithPossibleDuplicates, customization.Apps...)
 			}
 		}
 
@@ -1177,6 +1177,25 @@ func (api *API) maybeInjectSubAgentIntoContainerLocked(ctx context.Context, dc c
 		}
 		slices.Sort(displayApps)
 
+		appSlugs := make(map[string]struct{})
+		apps := make([]SubAgentApp, 0, len(appsWithPossibleDuplicates))
+
+		// We want to deduplicate the apps based on their slugs here.
+		// As we want to prioritize later apps, we will walk through this
+		// backwards.
+		for _, app := range slices.Backward(appsWithPossibleDuplicates) {
+			if _, slugAlreadyExists := appSlugs[app.Slug]; slugAlreadyExists {
+				continue
+			}
+
+			appSlugs[app.Slug] = struct{}{}
+			apps = append(apps, app)
+		}
+
+		// Apps is currently in reverse order here, so by reversing it we restore
+		// it to the original order.
+		slices.Reverse(apps)
+
 		subAgentConfig.DisplayApps = displayApps
 		subAgentConfig.Apps = apps
 	}
diff --git a/agent/agentcontainers/api_test.go b/agent/agentcontainers/api_test.go
@@ -1688,6 +1688,48 @@ func TestAPI(t *testing.T) {
 					assert.Equal(t, int32(3), subAgent.Apps[2].Order)
 				},
 			},
+			{
+				name: "AppDeduplication",
+				customization: []agentcontainers.CoderCustomization{
+					{
+						Apps: []agentcontainers.SubAgentApp{
+							{
+								Slug:   "foo-app",
+								Hidden: true,
+								Order:  1,
+							},
+							{
+								Slug: "bar-app",
+							},
+						},
+					},
+					{
+						Apps: []agentcontainers.SubAgentApp{
+							{
+								Slug:  "foo-app",
+								Order: 2,
+							},
+							{
+								Slug: "baz-app",
+							},
+						},
+					},
+				},
+				afterCreate: func(t *testing.T, subAgent agentcontainers.SubAgent) {
+					require.Len(t, subAgent.Apps, 3)
+
+					// As the original "foo-app" gets overriden by the later "foo-app",
+					// we expect "bar-app" to be first in the order.
+					assert.Equal(t, "bar-app", subAgent.Apps[0].Slug)
+					assert.Equal(t, "foo-app", subAgent.Apps[1].Slug)
+					assert.Equal(t, "baz-app", subAgent.Apps[2].Slug)
+
+					// We do not expect the properties from the original "foo-app" to be
+					// carried over.
+					assert.Equal(t, false, subAgent.Apps[1].Hidden)
+					assert.Equal(t, int32(2), subAgent.Apps[1].Order)
+				},
+			},
 		}
 
 		for _, tt := range tests {
