Can't subst \$( in Textfile

[datalogics-robb]

Describe the bug
Generating .NET Core csproj files I needed to insert this string literal into the output
NETCore\bin\$(Platform)\$(Configuration)\

But there does not seem to be any way to output the sequence \$(

To reproduce clone this:
https://github.com/datalogics-robb/quote-test-scons

run scons to generate GenFile.csproj and observe this string in the output:
NETCore\bin\$Platform)\$Configuration)\

SCons version 4.2.0
CPython 3.9.[67] tested on Mac/Linux

[mwichmann]

Just capturing what was noted on Discord, although I got some details wrong there - the code uses some different conventions and it tripped me up. The textfile tool (which also implements substfile) sets up an action function which does substitution on the values in the SUBST_DICT, using env.subst(value). With no keyword args, this defaults to raw=0 which will end up calling scons_subst with SUBST_CMD. But the intended usage here is just a plain textual substitution, not either the fancy "for command line" or the alternative "for signature", so this is probably not what's wanted in this context. Suggest adding raw=1 (not raw=True as I said in the Discord thread).