feat(ci): add Docker-based Java code generation testing by YadavAkhileshh · Pull Request #200 · accordproject/concerto-codegen

YadavAkhileshh · 2026-02-19T20:10:41Z

Summary

This PR adds automated Docker-based testing for Java code generation
as a proof-of-concept for GSoC 2026 Project # 6 (Testing for Code
Generation Targets).

What's Added

Dockerfile with Java 11 (eclipse-temurin) + Node.js 18 environment
GitHub Actions workflow that runs the Docker test on every push/PR

Why

Currently there is no automated way to verify that generated Java code
actually compiles correctly. This sets up the infrastructure to do that.

Future Work (if selected for GSoC)

Add testing for other languages: Go, TypeScript, Python, C#
Add actual code generation + javac compilation test
Add Docker images for each supported language target

Relates to GSoC 2026 Project # 6

Signed-off-by: Yadav Akhilesh yadavakhil2501@gmail.com

Copilot

Pull request overview

Adds a new CI workflow intended to validate Java target code generation by running a Docker-based test environment on pushes and PRs to main.

Changes:

Adds a GitHub Actions workflow to build the project and run a Docker-based Java codegen test.
Adds a Java+Node Docker image definition for codegen testing.
Adds a shell script intended to generate a sample CTO, generate Java, and compile it with javac.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 8 comments.

File	Description
`.github/workflows/test-java-codegen.yml`	Introduces a CI job to build and run a Docker-based Java codegen test.
`.github/docker/codegen-tests/java/Dockerfile`	Defines a Java 11 + Node 18 Docker environment for running codegen tests.
`.github/docker/codegen-tests/java/test-java.sh`	Implements the proof-of-concept CTO→Java generation + `javac` compilation script.

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Copilot · 2026-03-07T20:17:55Z

.github/docker/codegen-tests/java/Dockerfile

+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+CMD ["bash", "-c", "echo 'Testing environment...' && javac -version && node --version && echo '✅ Java + Node.js ready!'"]


The image CMD only prints tool versions and never runs test-java.sh, so docker run concerto-java-test won't execute any Java code generation/compilation checks. Copy the test script into the image and set ENTRYPOINT/CMD to run it (or remove the CMD and have the workflow run the script explicitly).

Suggested change

CMD ["bash", "-c", "echo 'Testing environment...' && javac -version && node --version && echo '✅ Java + Node.js ready!'"]

COPY test-java.sh /test/test-java.sh

RUN chmod +x /test/test-java.sh

CMD ["bash", "/test/test-java.sh"]

Copilot · 2026-03-07T20:17:55Z

.github/docker/codegen-tests/java/test-java.sh

+mkdir -p /test/output
+cd /test/output
+


This script writes under /test (a host-mounted directory in the workflow) while the container runs as root by default. That will create root-owned files (/test/output, compiled .class, potentially node_modules) in the GitHub Actions workspace and can break later steps/cleanup. Prefer writing to a container-only temp dir (e.g., under /tmp) or run the container with --user to match the runner UID/GID.

Copilot · 2026-03-07T20:17:56Z

.github/docker/codegen-tests/java/test-java.sh

+cat test.cto
+
+cd /test
+npm install


npm install is non-reproducible compared to npm ci and will also re-run lifecycle scripts and potentially mutate package-lock.json/node_modules in the mounted workspace. For CI-style execution, use npm ci (or skip install entirely if the workflow already ran npm ci and you rely on the mounted node_modules).

Suggested change

npm install

npm ci

Copilot · 2026-03-07T20:17:56Z

.github/docker/codegen-tests/java/test-java.sh

+const fs = require('fs');
+const cto = fs.readFileSync('/test/output/test.cto', 'utf8');
+const codeGen = new CodeGen(cto);
+const javaCode = codeGen.generate('Java');
+fs.writeFileSync('/test/output/Person.java', javaCode);


CodeGen exported by @accordproject/concerto-codegen is not a constructor (it exports visitor classes / a formats map). new CodeGen(cto) will throw at runtime. Use the supported visitor-based flow (e.g., ModelManager.accept(new CodeGen.formats.java(), { fileWriter, ... })) to generate output.

Suggested change

const fs = require('fs');

const cto = fs.readFileSync('/test/output/test.cto', 'utf8');

const codeGen = new CodeGen(cto);

const javaCode = codeGen.generate('Java');

fs.writeFileSync('/test/output/Person.java', javaCode);

const { ModelManager } = require('@accordproject/concerto-core');

const fs = require('fs');

const path = require('path');

const cto = fs.readFileSync('/test/output/test.cto', 'utf8');

const modelManager = new ModelManager();

modelManager.addModelFile(cto, 'test.cto');

const outputDir = '/test/output';

const fileWriter = {

currentFile: null,

files: {},

openFile: function (fileName) {

this.currentFile = fileName;

this.files[fileName] = [];

},

writeLine: function (line) {

if (!this.currentFile) {

throw new Error('No file is currently open for writing.');

}

this.files[this.currentFile].push(line);

},

closeFile: function () {

if (!this.currentFile) {

return;

}

const fileName = this.currentFile;

const content = this.files[fileName].join('\n') + '\n';

const fullPath = path.join(outputDir, fileName);

fs.writeFileSync(fullPath, content, 'utf8');

this.currentFile = null;

}

};

modelManager.accept(new CodeGen.formats.java(), { fileWriter });

Copilot · 2026-03-07T20:17:56Z

.github/docker/codegen-tests/java/test-java.sh

+const fs = require('fs');
+const cto = fs.readFileSync('/test/output/test.cto', 'utf8');
+const codeGen = new CodeGen(cto);
+const javaCode = codeGen.generate('Java');


The format key in this repo is lowercase (java), not 'Java' (see lib/codegen/codegen.js formats). Using 'Java' will fail even once the generator call is corrected.

Suggested change

const javaCode = codeGen.generate('Java');

const javaCode = codeGen.generate('java');

Copilot · 2026-03-07T20:17:56Z

.github/workflows/test-java-codegen.yml

+    - uses: actions/checkout@v3
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v3
+      with:
+        node-version: '18'
+
+    - name: Install dependencies
+      run: npm ci
+
+    - name: Build project
+      run: npm run build
+
+    - name: Build Docker image for Java testing
+      run: |
+        docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .
+
+    - name: Test Java code generation in Docker
+      run: |
+        docker run --rm \
+          -v "$(pwd):/test" \
+          concerto-java-test


steps: is followed by list items that are not indented under it, which makes this workflow YAML invalid and prevents the job from running. Indent the - uses: / - name: entries two more spaces so they are children of steps:.

Suggested change

- uses: actions/checkout@v3

- name: Set up Node.js

uses: actions/setup-node@v3

with:

node-version: '18'

- name: Install dependencies

run: npm ci

- name: Build project

run: npm run build

- name: Build Docker image for Java testing

run: |

docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .

- name: Test Java code generation in Docker

run: |

docker run --rm \

-v "$(pwd):/test" \

concerto-java-test

- uses: actions/checkout@v3

- name: Set up Node.js

uses: actions/setup-node@v3

with:

node-version: '18'

- name: Install dependencies

run: npm ci

- name: Build project

run: npm run build

- name: Build Docker image for Java testing

run: |

docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .

- name: Test Java code generation in Docker

run: |

docker run --rm \

-v "$(pwd):/test" \

concerto-java-test

Copilot · 2026-03-07T20:17:57Z

.github/workflows/test-java-codegen.yml

+      run: |
+        docker run --rm \
+          -v "$(pwd):/test" \
+          concerto-java-test


This docker run executes the image's default CMD, but the Dockerfile currently only prints versions and exits—so no Java code generation/compilation is actually tested. Either set the image entrypoint/CMD to run the test script, or invoke the script explicitly in this step (e.g., docker run ... bash /test/.github/docker/codegen-tests/java/test-java.sh).

Suggested change

concerto-java-test

concerto-java-test \

bash /test/.github/docker/codegen-tests/java/test-java.sh

Copilot · 2026-03-07T20:17:57Z

.github/workflows/test-java-codegen.yml

+
+    - name: Build Docker image for Java testing
+      run: |
+        docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .


The Docker build context is set to . after npm ci/npm run build, which will include node_modules and other artifacts in the build context upload even though the Dockerfile doesn't use them. Consider using .github/docker/codegen-tests/java as the build context (or add a .dockerignore / reorder steps) to avoid slow, large context transfers in CI.

Suggested change

docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .

docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .github/docker/codegen-tests/java

YadavAkhileshh added 2 commits February 20, 2026 01:24

feat(ci): add Docker-based Java code generation testing

2f9c5c9

fix(ci): fix Docker CMD to not rely on external script file

1adff6c

github-actions bot mentioned this pull request Mar 4, 2026

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mttrbrts requested a review from Copilot March 7, 2026 20:13

Copilot started reviewing on behalf of mttrbrts March 7, 2026 20:14 View session

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feat(ci): add Docker-based Java code generation testing#200

feat(ci): add Docker-based Java code generation testing#200
YadavAkhileshh wants to merge 2 commits intoaccordproject:mainfrom
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YadavAkhileshh commented Feb 19, 2026 •

edited

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-CMD ["bash", "-c", "echo 'Testing environment...' && javac -version && node --version && echo '✅ Java + Node.js ready!'"]
+COPY test-java.sh /test/test-java.sh
+RUN chmod +x /test/test-java.sh
+CMD ["bash", "/test/test-java.sh"]

-const fs = require('fs');
-const cto = fs.readFileSync('/test/output/test.cto', 'utf8');
-const codeGen = new CodeGen(cto);
-const javaCode = codeGen.generate('Java');
-fs.writeFileSync('/test/output/Person.java', javaCode);
+const { ModelManager } = require('@accordproject/concerto-core');
+const fs = require('fs');
+const path = require('path');
+const cto = fs.readFileSync('/test/output/test.cto', 'utf8');
+const modelManager = new ModelManager();
+modelManager.addModelFile(cto, 'test.cto');
+const outputDir = '/test/output';
+const fileWriter = {
+  currentFile: null,
+  files: {},
+  openFile: function (fileName) {
+    this.currentFile = fileName;
+    this.files[fileName] = [];
+  },
+  writeLine: function (line) {
+    if (!this.currentFile) {
+      throw new Error('No file is currently open for writing.');
+    }
+    this.files[this.currentFile].push(line);
+  },
+  closeFile: function () {
+    if (!this.currentFile) {
+      return;
+    }
+    const fileName = this.currentFile;
+    const content = this.files[fileName].join('\n') + '\n';
+    const fullPath = path.join(outputDir, fileName);
+    fs.writeFileSync(fullPath, content, 'utf8');
+    this.currentFile = null;
+  }
+};
+modelManager.accept(new CodeGen.formats.java(), { fileWriter });

	const javaCode = codeGen.generate('Java');
	const javaCode = codeGen.generate('java');

	concerto-java-test
	concerto-java-test \
	bash /test/.github/docker/codegen-tests/java/test-java.sh

	docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .
	docker build -t concerto-java-test -f .github/docker/codegen-tests/java/Dockerfile .github/docker/codegen-tests/java

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Summary

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Future Work (if selected for GSoC)

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YadavAkhileshh commented Feb 19, 2026 •

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