Is it really truly wrong to have an empty array for `files` in the config?

[danfuzz]

TypeScript Version: 2.1.4

Code

$ mkdir ts-error
$ cd ts-error
$ npm install typescript@2.1.4
$ echo '{"files": []}' > tsconfig.json
$ ./node_modules/.bin/tsc
error TS18002: The 'files' list in config file '/Users/danfuzz/testing/ts/tsconfig.json' is empty.

Expected behavior:

tsc doesn't complain about not actually getting asked to compile anything.

Actual behavior:

The error as noted.

Context:

It is of course pretty silly to actually use the TS compiler on the commandline and with an actual tsconfig.json in the way demo'ed here. However, in the case of using the ts-loader module to hook up the TS compiler to Webpack, this is how it sets itself up. (I'm just a user of ts-loader, not a developer of it, so please take this with a grain of salt.) AIUI ts-loader sets up the basic config with an empty files, and then makes separate calls to compile each file it's asked to, one at a time. This arrangement worked as of typescript version 2.0.10, but it broke as of 2.1.4.

I also filed TypeStrong/ts-loader#405 on ts-loader. It's not clear to me what the best way to address the issue is.

[danfuzz]

I understand that this change in behavior was intentional and for good reason, like, if you aren't intentionally asking not to compile anything, then it's probably bad if the compiler doesn't compile anything and also doesn't let you know.

So, by way of suggestion, maybe there can be an explicit config file flag that indicates "really, zero files are being listed intentionally."

[mhegazy]

We have added the error to avoid users calling the compiler with no input and wondering why they got no outputs.

tsloader calls the compiler API, it can change the config before passing it to the compiler.

[danfuzz]

it can change the config before passing it to the compiler.

But what can it change the config to in order to successfully tell TypeScript that it's okay that the config explicitly specifies zero files? Near as I can tell, there's nothing straightforward it can do to say that. (One workaround is to add a dummy entry to files.)

Adding a flag to that effect is the suggestion I made in the second comment on this bug, above.

[mhegazy]

add a single file that it is using? or ignore the errors? i have a made a similar change for ts-node: https://github.com/TypeStrong/ts-node/pull/226/files

[danfuzz]

In this case, there isn't actually any file at all (see original description). The config file is loaded (and specifies zero files), and then the resulting compiler is used to compile arbitrary individual files. Maybe ts-loader shouldn't be doing things that way, but before 2.1 it actually did demonstrably work.

[DanielRosenwasser]

So you're simply using TypeScript to verify your tsconfig.json?

[danfuzz]

Like I said before, I'm just a consumer of `ts-loader` who suddenly started seeing errors reported unexpectedly (with the version bump), and with only a basic understanding of how it's all hooked up. Please forgive my ignorance. Ultimately, that no-files config gets used / reused when actually compiling a file, but at the moment the compiler is instantiated, it doesn't have a list of files to compile, yet something *does* make a call to check the config file. You can see the code in question on the `ts-loader` bug I linked to. Thanks for looking into this.

[hilts-vaughan]

All my files are in filesGlob and am getting this error -- is there a way to silence this or at least check to make sure filesGlob OR files is not empty?

[DanielRosenwasser]

@hilts-vaughan why not use the include and exclude fields?

[hilts-vaughan]

Legacy reasons, mostly up until this point. Is filesGlob now deprecated? I don't see it here anymore: http://www.typescriptlang.org/docs/handbook/tsconfig-json.html

[hilts-vaughan]

It seems like it still does this even if include is non-empty.

[mhegazy]

fileGlobs was never a supported entry. It is an atom-typescript specific setting. Please share a tsconfig that is causing the message to show.

[DanielRosenwasser]

What I mean is that instead of using fileGlobs, use include. That way you won't get an error.

[aluanhaddad]

Also if you need to support filesGlob for some reason, you can still specify it in addition to include.