[bug #51414] Use of multiple $$% (for .SECONDEXPANSION) causes make to misinterpret the rule as a pattern rule

[Paul D. Smith]

Update of bug #51414 (project make):

                  Status:                    None => Not A Bug              
             Open/Closed:                    Open => Closed                 

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Follow-up Comment #1:

Actually what's happening is that your rule is being misinterpreted as a
static pattern rule, not a pattern rule, and it's not because you are using
$$%, it's because you are using a substitution reference in a secondary
expansion.  Also it doesn't matter how many uses of "$$%" you use; even one
substitution reference will show this problem.

Because you have used "$$" in the prerequisites list, make doesn't interpret
this as a variable reference.  That means the open parenthesis is not part of
a variable reference and has no special meaning to make.  So when make sees
this:


blahblah : $$(%:blah)


it tokenizes this string as "blahblah", ":", "$$(%", ":", "blah)".  The ":" IS
a special character to make, it's a rule separator.  When make sees a word
containing the special character "%" between two ":" characters it interprets
this to be a static pattern rule.  Because the "target" doesn't match the
pattern, you get this error.

I don't see any way to solve this problem: the grammar here is simply
ambiguous and make can't know what you mean.

In order to do what you want you cannot use a substitution reference
(directly) because of the ":" character in it.  You can either use a patsubst
function:


.SECONDEXPANSION:

libmy.a(my_source.o): $$(patsubst %_source.o,%,$$%)_internal.h


(here there's no ":" in the prereq list so it works).  Or you can use a
variable to hide the ":" and ensure that make parses things correctly:


nosource = $$(%:_source.o=)

.SECONDEXPANSION:

libmy.a(my_source.o): $$(nosource)_internal.h


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