Stricter TS checks in Vaadin 23.3.0

[javier-godoy]

Description of the bug

Vaadin 23.3.0 seems to introduce stricter TS checks by default.

I had to configure the following in tsconfig.json in order to run applications that were working fine with Vaadin 23.2:

"noImplicitAny": false,
"noImplicitThis": false,
"strictPropertyInitialization": false

(noImplicitAny and noImplicitThis were already true with Vaadin 23.2, but now they flag additional errors.)

See some sample error logs in FlowingCode/FontAwesomeIronIconset#56

The new stricter defaults are problematic, since they also affect third-party components (addons), which may rely on loose checks.

Expected behavior

Since it's not documented as a breaking change, I would expect no additional TS errors when upgrading from Vaadin 23.2 to Vaadin 23.3.0.

Minimal reproducible example

See https://github.com/FlowingCode/FontAwesomeIronIconset/tree/font-awesome-iron-iconset-4.2.0 (fixed in FlowingCode/FontAwesomeIronIconset#58)
and https://github.com/FlowingCode/XTermConsoleAddon/commits/xterm-console-2.1.0 (fixed in FlowingCode/XTermConsoleAddon#66)

The application runs with no issues up to vaadin 23.2 (mvn jetty:run), but it fails with TS errors with vaadin 23.3 and 24.

Versions

• Vaadin / Flow version: 23.3.0, 24.0.0.alpha5
• Java version: 11, 17
• OS version: Windows 10

[Artur-]

So what has changed as the options are still the same? Is it because of upgrading Typescript from 4.7 to 4.9?

[javier-godoy]

Is it because of upgrading Typescript from 4.7 to 4.9?

It seems so, although I cannot fully parse the TypeScript release notes.

Spelling out the details for one of the example cases I mentiones above:

1. Checkout branch flow-15485 from FlowingCode/FontAwesomeIronIconset (pom has vaadin 23.2.10)

git clone -b flow-15485 git@github.com:FlowingCode/FontAwesomeIronIconset.git

2. Run the demo application mvn jetty:run, open http://127.0.0.1:8080/ --> the application starts, no errors 🙂

3. mvn vaadin:dance

4. Edit pom and set 23.3.0

5. Delete tsconfig.json so that it's recreated with defaults.

6. mvn jetty:run, open http://127.0.0.1:8080/ --> the application starts, there are some errors 🙁

Property has no initializer and is not definitely assigned in the constructor. 

https://github.com/FlowingCode/FontAwesomeIronIconset/blob/flow-15485/src/test/resources/META-INF/resources/frontend/fc-font-awesome-gallery.ts#L9-L19

Variable implicitly has type 'any[]' in some locations where its type cannot be determined.
Variable implicitly has an 'any[]' type.

https://github.com/FlowingCode/FontAwesomeIronIconset/blob/flow-15485/src/test/resources/META-INF/resources/frontend/fc-font-awesome-gallery.ts#L67-L71

Object is possibly 'null'.

https://github.com/FlowingCode/FontAwesomeIronIconset/blob/9a7597b9092ffb382577fba1ac04a7e8662a08a5/src/test/resources/META-INF/resources/frontend/fc-font-awesome-gallery.ts#L79

7. rm -rf frontend/generated

8. Edit tsconfig.json and set "noImplicitAny": false and "strictPropertyInitialization": false

9. mvn jetty:run, open http://127.0.0.1:8080/ --> the application starts, there are less errors 🤨

Type 'string[]' is not assignable to type 'never[]'. Type 'string' is not assignable to type 'never'.
Object is possibly 'null'.

10. Edit tsconfig.json and set "strictNullChecks": false (https://stackoverflow.com/a/57563877/1297272)

11. Run the demo application mvn jetty:run, open http://127.0.0.1:8080/ --> the application starts, no errors 🙂

[Artur-]

It just hit me what the change is: the files from addons are validated as part of the build as they are placed inside frontend/generated/jar-resources. That folder should be excluded as you cannot change the code in the addons

[probert94]

I am facing the same issue in a multi module project I am working on.
During the build I get a lot of Parameter implicitly has an 'any' type. errors.
The files with the errors always come from "frontend/generated/jar-resources/src".
The errors are actually true but they are not shown on the real files ("META-INF/resources/frontend/src") neither in VS Code nor during the build.
When I (accidentally) open one of the generated files in VS Code, the error is shown there too, so it seems like a different tsconfig.json is used for the "real" files and the generated files.