Cannot read property 'getEntryByPath' of undefined

[atrauzzi]

TypeScript Version: 2.9.2
Search Terms: "Cannot read property 'getEntryByPath' of undefined"
Code
I couldn't even begin to guess what code is causing this. It's obviously one of my dependencies, but which? Well -- I guess that's the problem with this error...
Expected behavior: Either my application to work, or for ts to give me better feedback.
Actual behavior: I get an error that doesn't help me identify where the issue is.

Happy to answer any specific questions beyond the basic template. It's a webpack 4 project.

Try shrinking the project size until you something that can be reproduced. Also, this error shouldn't show up in the command line compiler, so it must have something to do with a tool you're using to compile.

[atrauzzi]

I'm using webpack 4 with ts-loader.

I definitely can get it to compile by making a trival console.log module. But obviously there's a huge gulf between the modules my project uses and that.

Is there nothing I can do/use to get better insights?

I would recommend making a copy of your project, then deleting things until the error disappears. The error probably has to do with webpack's use of TypeScript services rather than the particular content of the code, but maybe the error only reproduces with some particular pattern of imports / file references.

(The error message is not too ambiguous, but that doesn't mean we know why it happened. There is indeed a line hostCache = undefined!; in the code that is fishy, but supposedly we had some reason why hostCache wouldn't be referenced after that.)

Also, try using typescript@next in case this has already been fixed.

[atrauzzi]

Tried @next before opening issue, didn't help.

So, I decided to go to that chunk of typescript.js and try to get some output:

            function fileExists(fileName) {
                var path = ts.toPath(fileName, currentDirectory, getCanonicalFileName);
                console.log(fileName, path);
                var entry = hostCache.getEntryByPath(path);
                return entry ?
                    !ts.isString(entry) :
                    (host.fileExists && host.fileExists(fileName));
            }

/Users/atrauzzi/Development/project/node_modules/@material-ui/core/package.json /users/atrauzzi/development/project/node_modules/@material-ui/core/package.json

So, it looks like it's failing when trying to access the package.json for material-ui? This happens several times in a row. Not sure what to make of it or how I could possibly identify who is responsible for causing the error...

• Is it typescript for...not sure...?
• Is it ts-loader because they misused typescript somehow?
• Is it material-ui because they are doing some kind of bad import?

I guess the issue here is that yes, we know there's an error, obviously. But the feedback doesn't narrow any of it down.

It would be better to just try getting a smaller repro -- right now there are just too many variables in play. For example, if you remove material-ui it might reproduce with some other package in your build.

If you're seeing compile errors instead of a crash, that probably means the thing you removed was relevant to the error.

This is a bug tracker -- you appear to have discovered a real bug, but to fix it we'll need a repro. My recommendation was to make a copy of your project and to simplify that so we have a way to reproduce the bug -- not to destroy your original project.

[atrauzzi]

Heads up, doing a lot of trial and error this evening and it seems to be narrowing down to any time I import WithStyles or withStyles from Material UI. Tomorrow morning I'll try to make a repro repo, but if I can't get it, I'll at the very least do screenshots. I can cause/prevent the error predictably now based on the one module.

[kasperisager]

I'm hitting this same issue when TypeScript tries to infer the type of a seemingly innocent constant that is assigned the result of a function invocation, with the function residing in a separate module. If I explicitly annotate the constant with a type, which also resides in a separate module, things work. I've however been unable to reproduce this in anything but my own code base, though it might provide others with a lead 😕

[jamalsoueidan]

It happens to my project too.

[atrauzzi]

Alright, managed to get a repro going based off of a slice of my project. All build configuration is included as well as the yarn-error.log generated, although that's probably not helpful.

---

Download repro archive.

To run:

yarn install
yarn hot

---

Here's the output I'm getting:

[michitaro]

I'm hitting the same issue too.
Here is my minimal reproducing repository.
https://github.com/michitaro/typescript-issue-25047
{"declaration": false} helps the situation.

This change solves the error in my case.
https://github.com/michitaro/typescript-issue-25047/commit/6f440e2128245e37a1de65b2a79d7399b9719461
VNode is a return type of the function.