import os + use of existsDir/dirExists/existsFile/fileExists/findExe in config.nims causes "ambiguous call' error

[kaushalmodi]

In config.nims, when the os module is imported and one of these procs are used:

• existsDir or dirExists
• existsFile or fileExists
• findExe

we get the "ambiguous call" error (because these are defined in both system and os.

Example config.nims

1. Create this config.nims in any directory
2. Run nim temp123

# config.nims
import os # commenting this out fixes the error
# import os except existsDir, dirExists, existsFile, fileExists, findExe # this also does not give that error

task temp123, "Temp task":
  echo existsDir("/usr")
  echo dirExists("/usr")
  echo existsFile("/usr/foo")
  echo fileExists("/usr/foo")
  echo findExe("nim")

Current Output

/home/kmodi/sandbox/nim/bug_reports/nimscript_import_os/config.nims(4, 6) template/generic instantiation of `task` from here
/home/kmodi/sandbox/nim/bug_reports/nimscript_import_os/config.nims(5, 17) Error: ambiguous call; both system.existsDir(dir: string) [declared in /home/kmodi/usr_local/apps/6/nim/devel/lib/system/nimscript.nim(135, 6)] and os.existsDir(dir: string) [declared in /home/kmodi/usr_local/apps/6/nim/devel/lib/pure/os.nim(1109, 6)] match for: (string)

Expected Output

Outputs of the echo statements in the above example.

Workaround

• Use import os except existsDir, dirExists, existsFile, fileExists, findExe, or system. qualifiers with the ambiguous identifiers.

Additional Information

This issue is very closely related to #12835 .

$ nim -v
Nim Compiler Version 1.3.1 [Linux: amd64]
Compiled at 2020-04-27
Copyright (c) 2006-2020 by Andreas Rumpf

git hash: 2f1aad02642576d13df018c9e5869c8de7e3a539
active boot switches: -d:release

This used to work at some point (probably around Nim 19.x).

[timotheecour]

reduced example:
nim e foo.nim

# foo.nim
import os
echo dirExists("/tmp")

This used to work at some point (probably around Nim 19.x).

when ? 1.0.0 gives same error and 0.19.0 gives Error: cannot 'importc' variable at compile time

however, this is annoying so I'm (hopefully) fixing it here: #14143

[metagn]

Also getEnv, existsEnv, putEnv, delEnv, getCurrentDir. The following procs are also the same idea in os and nimscript but are renamed: removeDir -> rmDir, removeFile -> rmFile, moveDir -> mvDir, moveFile -> mvFile, createDir -> mkDir, copyFile -> cpFile, copyDir -> cpDir.

[Araq]

They are renamed for a reason!

[metagn]

Yes, I advocate for that. I don't think any procs should be deleted from nimscript, I just think they should be moved to os then import/exported. That will allow the renamed procs to be imported with an alias like from os import removeDir as rmDir, then export rmDir. This makes maintaining nimscript procs easier, you can find their declarations in the same place their compiled Nim versions are declared. Of course they aren't implemented there, but that's easy to clarify with a doc comment or a code comment in the when defined(nimscript) branch.

[Araq]

The rmDir set of operatings could be in a new module std / scripting but shouldn't be part of os.nim, their design is based on the idea that you can have a "what if" emulation run that doesn't touch your FS.

[kaushalmodi]

@Araq Would a fix similar to 3d2459b fix this too?

[Araq]

I think my fix mostly works. :-)