Cannot run conda 4.4 in a batch script

[isuruf]

For example if I run a .bat file with

conda --version
echo asd

then only the first line is executed.

cc @kalefranz, this is the reason for the error @jdblischak mentioned in #6527

[kalefranz]

Ok, this is all then related to something we've done in https://github.com/conda/conda/blob/1a3353accd4b782835b9736627f890337ff488c1/conda/shell/Library/bin/conda.bat

On Windows for conda 4.4, what you get when you type the command conda is actually that conda.bat file, and not conda.exe. It's a level of shell indirection for the cmd.exe shell. For other shells, bash for example, we've implemented conda as a shell function. Using this conda.bat file is what we were stuck with for cmd.exe though.

[kalefranz]

We probably need to add a lot of

@IF errorlevel 1 exit /b 1

checks to that file.

[isuruf]

Windows shell cmd.exe works differently than bash. When you run a batch script from one batch script control is given to the child script and the parent is simply stopped. To avoid this and have the child return control to the parent you need to use the command call.

Instead of

conda --version
echo asd

you now need to use

call conda --version
echo asd

otherwise the 2nd line will not be run anymore.

[kalefranz]

What if, instead, your bat script was

conda.exe --version
echo asd

Is that a possible fix? I realize, if it is a fix, it does require a change to existing code that was relying on old behavior. I'm afraid we might be stuck here with a solution like that though.

[isuruf]

Yes, that works, but the rest of conda.bat is not run. Isn't that a problem?

[isuruf]

Would conda be supporting using the activate.bat script in the future? If so, calling the activate script and then running conda.exe is okay

[kalefranz]

Would conda be supporting using the activate.bat script in the future?

We want to get rid of the activate "executable", because it has name collisions with something like virtualenv's activate. But I agree that we have an unsolved issue here before we can fully end up deprecating it.

but the rest of conda.bat is not run. Isn't that a problem?

The answer is, it depends. For now, using conda.exe instead of conda is no different than what we had in 4.3. Besides adding real conda activate and conda deactivate commands, the only other thing conda.bat does is call "reactivate" for install, update, and remove. But conda 4.3 never did "reactivate", so at least you're no worse off using conda.exe.

[mbargull]

Maybe we could add something like

@call :run
@goto :eof
:run

at the top of conda.bat to always run the rest inside a call? That just came to mind but I haven't tried it out yet.

[mbargull]

I'm not sure about the exit status propagation for this, though...

[kalefranz]

I was hoping you might have some ideas here @mbargull :)

[mbargull]

nvm, thinking about it, it is exactly as @isuruf said

When you run a batch script from one batch script control is given to the child script and the parent is simply stopped. To avoid this and have the child return control to the parent you need to use the command call.

So I'm not sure we can use a batch file-only solution if we want to make conda ... work without call in batch files :/ .. Am thinking about it some more time...

[kalefranz]

We're probably just stuck with the constraints of batch scripting and cmd.exe. Eventually when we have the conda.bat pattern more broadly established, maybe we can just switch everybody writing batch scripts to use call conda. In the interim, while people are flipping back and forth between 4.3 and 4.4, conda.exe seems like the best solution.

[mbargull]

Yeah, I can't come up with a solution which supports the non-call usage but uses conda.bat..
A question might be whether you would might just want to deprecate the old usage but support it until some 4.5 version [EDIT]gets released[/EDIT] to allow a transition phase. That would mean to not add shell/Library/bin to path on default for Windows, i.e., withheld the 4.4 shell function/conda activate feature on Windows for some time.

[kalefranz]

Lots of packages require that $PREFIX/Library/bin is added to PATH, on activate. So it would mean I think keeping conda.bat out of that directory.

I guess we could consider moving conda.bat to the $PREFIX/bin directory, but I'm not keen on that solution either.

    def _get_path_dirs(self, prefix):
        if on_win:  # pragma: unix no cover
            yield prefix.rstrip("\\")
            yield join(prefix, 'Library', 'mingw-w64', 'bin')
            yield join(prefix, 'Library', 'usr', 'bin')
            yield join(prefix, 'Library', 'bin')
            yield join(prefix, 'Scripts')
            yield join(prefix, 'bin')
        else:
            yield join(prefix, 'bin')

That set of paths for activate now is pretty set in stone. Those assumptions are baked into a bunch of existing conda packages.

[mbargull]

Ah, I just didn't look at the install scripts and thus didn't notice
https://github.com/conda/conda/blob/4.4.3/utils/functions.sh#L192-L196
and thought conda.bat would still be inside shell (with shell being added to also added to $PATH, too). Removing Library/bin from $PATH would of course be no option and moving conda.bat to bin doesn't sound good to me, likewise. Currently, I don't have any further ideas :/ ...
(Stupid CMD! Let's just dream of an utopia with world peace and a decommissioned CMD... dammit!)

[mingwandroid]

Well Powershell is deprecating cmd so I wonder if we shouldn't just do the best we can there (I know nothing about Powershell though) and support only using call for cmd?

[kalefranz]

All the other shell wrappers are working out pretty well I think. Even the conda.bat isn't that bad, although this is certainly and issue. So is the question of what we do when we deprecate activate.bat (I have ideas there).

Actually, the only wrapper that's still pending to go into 4.4 is the powershell one. I have NO experience there though, and really don't know the best practices "powershell way" on how to implement that. At least there are plenty of examples now in the conda/shell directory for all the other wrappers. And I did start #6471.

[mbargull]

and support only using call for cmd? (@mingwandroid)

Of course, I agree you should

just switch everybody writing batch scripts to use call conda (@kalefranz)

as soon as possible since I think the more unified shell handling with the wrappers, including conda.bat, is a really nice step forward! If it's possible to create a transitioning period, that would be nice, I guess, but if it's not easily done, pushing the unified concept should be more important, IMHO.
(As for Powershell, absolutely no experience here either -- scurried away from Windows before that became more widely known.)

[kalefranz]

scurried away from Windows before that became more widely known

I just installed powershell on my mac. 😱

pwsh

Yes, they changed the executable name for unix from what it is on Windows. Microsoft maybe just won't ever learn.

[isuruf]

Maybe this should go in another issue, but note that you'll run into trouble updating conda.bat in the future as the batch script will be changing itself and it'll error out if you change anything above the invocation to conda.exe.

[kalefranz]

[kalefranz]

Maybe this should go in another issue, but note that you'll run into trouble updating conda.bat in the future as the batch script will be changing itself and it'll error out if you change anything above the invocation to conda.exe.

I actually think we have this problem all the time now. We've tried to deal with it multiple times in multiple ways, and where we are right now with it is #6631. Trying again to address the issue in #6660, but I've sunk a lot of time into that and still haven't been successful yet.

[kalefranz]

I think it's safe to close this issue now. Let me know if anyone disagrees.

[certik]

This really should be documented somewhere. It took me hours to figure out I have to put "call" in front of conda, otherwise the rest of the file is not executed.

[sytelus]

I want to share my scripts between Windows and Linux and this issue is breaking it. I hope conda.bat can be eliminated and conda.exe itself executes all necessary code so this hack is not needed.

[sbourdeauducq]

Well that's conda for you; you may want to try MSYS2 if you want to get things done.

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