cmd_bat quoted args escaping

[stdbug]

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Description of the problem / feature request:

genrules cmd_bat argument quoting results in incorrect syntax/"The system cannot find the file specified"

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

create a random file so that it's full path contains a space, then

genrule(
    name = "test",
    outs = ["test.txt"],
    cmd_bat = "copy \"C:\\New folder\\test.txt\" $(@D)\\test.txt",
)

OR

genrule(
    name = "test",
    outs = ["test.txt"],
    cmd_bat = """copy "C:\\New folder\\test.txt" $(@D)\\test.txt""",
)

What operating system are you running Bazel on?

Windows 10 x64

What's the output of bazel info release?

release 3.4.1

Have you found anything relevant by searching the web?

No

Any other information, logs, or outputs that you want to share?

Dumping the command by adding echo in front of copy:

genrule(
    name = "test",
    outs = ["test.txt"],
    cmd_bat = """echo copy "C:\\New folder\\test.txt" > $(@D)\\test.txt""",
)

shows that cmd.exe actually gets

copy \"C:\New folder\test.txt\"

which is not accepted by cmd.exe