# $NetBSD: directive-for-escape.mk,v 1.16 2022/06/12 16:09:21 rillig Exp $ # # Test escaping of special characters in the iteration values of a .for loop. # These values get expanded later using the :U variable modifier, and this # escaping and unescaping must pass all characters and strings effectively # unmodified. .MAKEFLAGS: -df # Even though the .for loops take quotes into account when splitting the # string into words, the quotes don't need to be balanced, as of 2020-12-31. # This could be considered a bug. ASCII= !"\#$$%&'()*+,-./0-9:;<=>?@A-Z[\]_^a-z{|}~ # XXX: As of 2020-12-31, the '#' is not preserved in the expanded body of # the loop. Not only would it need the escaping for the variable modifier # ':U' but also the escaping for the line-end comment. .for chars in ${ASCII} . info ${chars} .endfor # As of 2020-12-31, using 2 backslashes before be '#' would treat the '#' # as comment character. Using 3 backslashes doesn't help either since # then the situation is essentially the same as with 1 backslash. # This means that a '#' sign cannot be passed in the value of a .for loop # at all. ASCII.2020-12-31= !"\\\#$$%&'()*+,-./0-9:;<=>?@A-Z[\]_^a-z{|}~ .for chars in ${ASCII.2020-12-31} . info ${chars} .endfor # Cover the code in ExprLen. # # XXX: It is unexpected that the variable V gets expanded in the loop body. # The double '$$' should intuitively prevent exactly this. Probably nobody # was adventurous enough to use literal dollar signs in the values of a .for # loop, allowing this edge case to go unnoticed for years. # # See for.c, function ExprLen. V= value VALUES= $$ $${V} $${V:=-with-modifier} $$(V) $$(V:=-with-modifier) .for i in ${VALUES} . info $i .endfor # Try to cover the code for nested '{}' in ExprLen, without success. # # The value of the variable VALUES is not meant to be a variable expression. # Instead, it is meant to represent literal text, the only escaping mechanism # being that each '$' is written as '$$'. VALUES= $${UNDEF:U\$$\$$ {{}} end} # # The .for loop splits ${VALUES} into 3 words, at the space characters, since # the '$$' is an ordinary character and the spaces are not escaped. # Word 1 is '${UNDEF:U\$\$' # Word 2 is '{{}}' # Word 3 is 'end}' # # Each of these words is now inserted in the body of the .for loop. .for i in ${VALUES} # $i .endfor # # When these words are injected into the body of the .for loop, each inside a # '${:U...}' expression, the result is: # # expect: For: loop body: # expect: # ${:U\${UNDEF\:U\\$\\$} # expect: For: loop body: # expect: # ${:U{{\}\}} # expect: For: loop body: # expect: # ${:Uend\}} # expect: For: end for 1 # # The first of these expressions is the most interesting one, due to its many # special characters. This expression is properly balanced: # # Text Meaning Explanation # \$ $ escaped # { { ordinary text # UNDEF UNDEF ordinary text # \: : escaped # U U ordinary text # \\ \ escaped # $\ (expr) an expression, the variable name is '\' # \$ $ escaped # # To make the expression '$\' visible, define it to an actual word: ${:U\\}= backslash .for i in ${VALUES} . info $i .endfor # # expect-3: ${UNDEF:U\backslash$ # expect-4: {{}} # expect-5: end} # # FIXME: There was no expression '$\' in the original text of the variable # 'VALUES', that's a surprise in the parser. # Second try to cover the code for nested '{}' in ExprLen. # # XXX: It is not the job of ExprLen to parse an expression, it is naive to # expect ExprLen to get all the details right in just a few lines of code. # Each variable modifier has its own inconsistent way of parsing nested # variable expressions, braces and parentheses. (Compare ':M', ':S', and # ':D' for details.) The only sensible thing to do is therefore to let # Var_Parse do all the parsing work. VALUES= begin<$${UNDEF:Ufallback:N{{{}}}}>end .for i in ${VALUES} . info $i .endfor # A single trailing dollar doesn't happen in practice. # The dollar sign is correctly passed through to the body of the .for loop. # There, it is expanded by the .info directive, but even there a trailing # dollar sign is kept as-is. .for i in ${:U\$} . info ${i} .endfor # As of 2020-12-31, the name of the iteration variable can even contain # colons, which then affects variable expressions having this exact modifier. # This is clearly an unintended side effect of the implementation. NUMBERS= one two three .for NUMBERS:M*e in replaced . info ${NUMBERS} ${NUMBERS:M*e} .endfor # As of 2020-12-31, the name of the iteration variable can contain braces, # which gets even more surprising than colons, since it allows to replace # sequences of variable expressions. There is no practical use case for # this, though. BASENAME= one EXT= .c .for BASENAME}${EXT in replaced . info ${BASENAME}${EXT} .endfor # Demonstrate the various ways to refer to the iteration variable. i= outer i2= two i,= comma .for i in inner . info . $$i: $i . info . $${i}: ${i} . info . $${i:M*}: ${i:M*} . info . $$(i): $(i) . info . $$(i:M*): $(i:M*) . info . $${i$${:U}}: ${i${:U}} . info . $${i\}}: ${i\}} # XXX: unclear why ForLoop_SubstVarLong needs this . info . $${i2}: ${i2} . info . $${i,}: ${i,} . info . adjacent: $i${i}${i:M*}$i .endfor # The variable name can be a single '$' since there is no check on valid # variable names. ForLoop_SubstVarShort skips "stupid" variable names though, # but ForLoop_SubstVarLong naively parses the body of the loop, substituting # each '${$}' with an actual 'dollar'. .for $ in dollar . info eight $$$$$$$$ and no cents. . info eight ${$}${$}${$}${$} and no cents. .endfor # Outside a .for loop, '${$}' is interpreted differently. The outer '$' starts # a variable expression. The inner '$' is followed by a '}' and is thus a # silent syntax error, the '$' is skipped. The variable name is thus '', and # since since there is never a variable named '', the whole expression '${$}' # evaluates to an empty string. closing-brace= } # guard against an ${closing-brace}= # alternative interpretation .info eight ${$}${$}${$}${$} and no cents. # What happens if the values from the .for loop contain a literal newline? # Before for.c 1.144 from 2021-06-25, the newline was passed verbatim to the # body of the .for loop, where it was then interpreted as a literal newline, # leading to syntax errors such as "Unclosed variable expression" in the upper # line and "Invalid line type" in the lower line. .for i in "${.newline}" . info short: $i . info long: ${i} .endfor # No error since the newline character is not actually used. .for i in "${.newline}" .endfor # Between for.c 1.161 from 2022-01-08 and before for.c 1.163 from 2022-01-09, # a newline character in a .for loop led to a crash since at the point where # the error message including the stack trace is printed, the body of the .for # loop is assembled, and at that point, ForLoop.nextItem had already been # advanced. .MAKEFLAGS: -dp .for i in "${.newline}" : $i .endfor .MAKEFLAGS: -d0 .MAKEFLAGS: -df .for i in \# \\\# # $i .endfor .for i in $$ $$i $$(i) $${i} $$$$ $$$$$$$$ $${:U\$$\$$} # $i .endfor # The expression '${.TARGET}' must be preserved as it is one of the 7 built-in # target-local variables. See for.c 1.45 from 2009-01-14. .for i in ${.TARGET} $${.TARGET} $$${.TARGET} $$$${.TARGET} # $i .endfor # expect: # ${:U${.TARGET}} # XXX: Why does '$' result in the same text as '$$'? # expect: # ${:U${.TARGET}} # XXX: Why does the '$$' before the '${.TARGET}' lead to an escaped '}'? # expect: # ${:U$${.TARGET\}} # XXX: Why does '$' result in the same text as '$$'? # XXX: Why does the '$$' before the '${.TARGET}' lead to an escaped '}'? # expect: # ${:U$${.TARGET\}} .for i in ((( {{{ ))) }}} # $i .endfor .MAKEFLAGS: -d0 all: