> > Another thing to keep in mind is that not all host languages may be > capable of expressing a string with NUL in it. Most notably, shell. > The --shell quoting rule used by for-each-ref would produce an > equivalent of the "script" produced like this: > > $ tr Q '\000' >script <<\EOF > #!/bin/sh > varname='varQname' > echo "$varname" > EOF > > but I do not think it would say 'var' followed by a NUL followed by > 'name'. The NUL is likely lost when assigned to the variable. > Yes, in the following example you mentioned earlier, I have also noticed the loss of '\0'. > > git for-each-ref --format=' > > name=%(refname) > > var=%(placeholder) > > mkdir -p "$(dirname "$name")" > > printf "%%s" "$var" >"$name" > > ' --shell | /bin/sh > > > So for some host languages, binaries may be useless with or without > quoting. But for ones that can use strings to hold arbitrary byte > sequence, it should be OK to let for-each-ref to quote the byte > sequence as a string literal for the language (so that the exact > byte sequence will end up being in the variable after assignment). > I agree, and maybe some'\0' can be escaped appropriately to let host languages recognize it.... > That reminds me of another thing. The --python thing was written > back when Python3 was still a distant dream and strings were the > appropriate type for a random sequence of bytes (as opposed to > unicode, which cannot have a random sequence of bytes). Somebody > needs to check if it needs any update to work with Python3. $ printf '%b' "name='a\\\0b\\\0c'\nprint(name)" | python2.7 | od -c 0000000 a \0 b \0 c \n 0000006 $ printf '%b' "name='a\\\0b\\\0c'\necho -e \"\$name\"" | sh | od -c 0000000 a \0 b \0 c \n 0000006 In shell or python2/3, we can replace'\0' with "\\0". In Tcl and perl, they are ok with '\0'. $ printf '%b' "set name \"a\0b\0c\"\nputs \$name" | tclsh | od -c 0000000 ' a \0 b \0 c ' \n 0000010 $ printf '%b' "\$name = 'a\0b\0c';\n print \"\$name\"" | perl | od -c 0000000 a \0 b \0 c 0000005 So I currently think that a possible strategy is to modify `python_quote_buf_with_size()` and `sq_quote_buf_with_size()` from '\0' to "\\0". Thanks! -- ZheNing Hu
