IFileSystem.fileExists returns false even when a file exists.

[DonJayamanne]

This breaks conda and virtual environments

• These environments are no longer listed as interpreters, hence absolutely nothing works for conda or virtual environments.

In master.
I believe the logic of checking the file stat is incorrect.
We're checking if the file type == FIle when checking if a file exists.
However fstat could indicate that its a symbolic link.

Not sure this is the issue, but likely. Either way still is incorrect.

I.e. I don't think we should be comparing == File, we might want to check if !== Directory instead. I.e. allow other values except directory. I.e. its possible Unknown could be returned for a file (just as with symbolic links & others).

Proposed solution

• If checking for a file, then ensure fstat !== direcrtory
• If checking for a directory, then ensure fstat !== file

[DonJayamanne]

The problem is we're treating the FileType as an enum and comparing ===.
However these are bit values and we need to use bitwise operations.

[DonJayamanne]

Other issues across the code:

• We have other issues in the code as well if (await this.fs.fileExists(dir)) {
  • Tests cannot catch this. Its possible we've made similar mistakes elsewhere (possibly due to find replace).
• Checking === instead of using bitwise operations.

    public async getFiles(dirname: string): Promise<string[]> {
        return (await this.listdir(dirname))
            .filter(([_name, fileType]) => fileType === FileType.File)
            .map(([name, _fileType]) => this.paths.join(dirname, name));
    }

@ericsnowcurrently @karthiknadig /cc

[ericsnowcurrently]

The old code for fileExists() used fs.Stats.isFile(), which is equivalent to checking for FileType.File. I don't think there's a need to change that approach.

[DonJayamanne]

@ericsnowcurrently
Please see my comment here #8890 (comment)
That's where the bug is.

[ericsnowcurrently]

Right. I have a fix for that. :)