Prevent user from adding the same dependency multiple times (#859)

pages/_type/_id/version.vue

@@ -1176,6 +1176,18 @@ export default {
           const project = (await this.$axios.get(`project/${newDependencyId}`))
             .data
 
+          if (
+            this.version.dependencies.some(
+              (dep) => project.id === dep.project_id
+            )
+          ) {
+            this.$notify({
+              group: 'main',
+              title: 'Dependency already added',
+              text: 'You cannot add the same dependency twice.',
+              type: 'error',
+            })
+          } else {
             this.version.dependencies.push({
               project,
               project_id: project.id,
@@ -1187,6 +1199,7 @@ export default {
               projects: this.dependencies.projects.concat([project]),
               versions: this.dependencies.versions,
             })
+          }
         } else if (dependencyAddMode === 'version') {
           const version = (
             await this.$axios.get(`version/${this.newDependencyId}`)
@@ -1196,6 +1209,18 @@ export default {
             await this.$axios.get(`project/${version.project_id}`)
           ).data
 
+          if (
+            this.version.dependencies.some(
+              (dep) => version.id === dep.version_id
+            )
+          ) {
+            this.$notify({
+              group: 'main',
+              title: 'Dependency already added',
+              text: 'You cannot add the same dependency twice.',
+              type: 'error',
+            })
+          } else {
             this.version.dependencies.push({
               version,
               project,
@@ -1212,6 +1237,7 @@ export default {
               versions: this.dependencies.versions.concat([version]),
             })
           }
+        }
 
         this.newDependencyId = ''
       } catch {