fix: pipeline variables's value should be nullable

src/data-expander.ts

@@ -213,7 +213,9 @@ export function defaults (gitlabData: any) {
 
 export function globalVariables (gitlabData: any) {
     for (const [key, value] of Object.entries<any>(gitlabData.variables ?? {})) {
-        if (Utils.isObject(value)) {
+        if (value === null) {
+            gitlabData.variables[key] = ""; // variable's values are nullable
+        } else if (Utils.isObject(value)) {
             gitlabData.variables[key] = value["value"];
         }
     }

src/parser.ts

@@ -106,7 +106,9 @@ export class Parser {
 
         // Check job variables for invalid hash of key value pairs, and cast numbers to strings
         Utils.forEachRealJob(gitlabData, (jobName, jobData) => {
-            for (const [key, value] of Object.entries(jobData.variables || {})) {
+            for (const [key, _value] of Object.entries(jobData.variables || {})) {
+                let value = _value;
+                if (value === null) value = ""; // variable's values are nullable
                 assert(
                     typeof value === "string" || typeof value === "number",
                     chalk`{blueBright ${jobName}} has invalid variables hash of key value pairs. ${key}=${value}`

tests/test-cases/variables-null/.gitlab-ci.yml

@@ -0,0 +1,9 @@
+---
+variables:
+  EMPTY_GLOBAL_VAR:
+test-job:
+  variables:
+    EMPTY_JOB_VAR:
+  script:
+    - echo "EMPTY_GLOBAL_VAR:${EMPTY_GLOBAL_VAR}"
+    - echo "EMPTY_JOB_VAR:${EMPTY_JOB_VAR}"

tests/test-cases/variables-null/integration.variables-null.test.ts

@@ -0,0 +1,26 @@
+import {WriteStreamsMock} from "../../../src/write-streams";
+import {handler} from "../../../src/handler";
+import chalk from "chalk";
+import {initSpawnSpy} from "../../mocks/utils.mock";
+import {WhenStatics} from "../../mocks/when-statics";
+
+beforeAll(() => {
+    initSpawnSpy(WhenStatics.all);
+});
+
+test("variable-null <test-job>", async () => {
+    const writeStreams = new WriteStreamsMock();
+    await handler({
+        cwd: "tests/test-cases/variables-null",
+        job: ["test-job"],
+    }, writeStreams);
+
+    const expected = [
+        chalk`{blueBright test-job} {green $ echo \"EMPTY_GLOBAL_VAR:\${EMPTY_GLOBAL_VAR\}\"}`,
+        chalk`{blueBright test-job} {greenBright >} EMPTY_GLOBAL_VAR:`,
+        chalk`{blueBright test-job} {green $ echo \"EMPTY_JOB_VAR:\${EMPTY_JOB_VAR\}\"}`,
+        chalk`{blueBright test-job} {greenBright >} EMPTY_JOB_VAR:`,
+    ];
+
+    expect(writeStreams.stdoutLines.slice(1, -3)).toEqual(expected);
+});