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https://github.com/freebsd/freebsd-src
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1b65f0bd2b
o allow env var MAKE_OBJDIR_CHECK_WRITABLE=no to skip writable checks in InitObjdir. Explicit .OBJDIR target always allows read-only directory. o Fix building and unit-tests on non-BSD. o More code cleanup and refactoring. o More unit tests
74 lines
2.2 KiB
Makefile
Executable file
74 lines
2.2 KiB
Makefile
Executable file
# $NetBSD: cond-undef-lint.mk,v 1.3 2020/11/15 14:58:14 rillig Exp $
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#
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# Tests for defined and undefined variables in .if conditions, in lint mode.
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#
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# As of 2020-09-14, lint mode contains experimental code for printing
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# accurate error messages in case of undefined variables, instead of the
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# wrong "Malformed condition".
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#
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# See also:
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# opt-debug-lint.mk
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.MAKEFLAGS: -dL
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# DEF is defined, UNDEF is not.
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DEF= defined
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# An expression based on a defined variable is fine.
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.if !${DEF}
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. error
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.endif
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# Since the condition fails to evaluate, neither of the branches is taken.
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.if ${UNDEF}
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. error
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.else
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. error
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.endif
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# The variable name depends on the undefined variable, which is probably a
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# mistake. The variable UNDEF, as used here, can be easily turned into
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# an expression that is always defined, using the :U modifier.
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#
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# The outer expression does not generate an error message since there was
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# already an error evaluating this variable's name.
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#
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# TODO: Suppress the error message "Variable VAR. is undefined". That part
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# of the expression must not be evaluated at all.
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.if ${VAR.${UNDEF}}
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. error
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.else
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. error
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.endif
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# The variable VAR.defined is not defined and thus generates an error message.
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#
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# TODO: This pattern looks a lot like CFLAGS.${OPSYS}, which is at least
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# debatable. Or would any practical use of CFLAGS.${OPSYS} be via an indirect
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# expression, as in the next example?
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.if ${VAR.${DEF}}
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. error
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.else
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. error
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.endif
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# Variables that are referenced indirectly may be undefined in a condition.
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#
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# A practical example for this is CFLAGS, which consists of CWARNS, COPTS
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# and a few others. Just because these nested variables are not defined,
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# this does not make the condition invalid.
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#
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# The crucial point is that at the point where the variable appears in the
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# condition, there is no way to influence the definedness of the nested
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# variables. In particular, there is no modifier that would turn undefined
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# nested variables into empty strings, as an equivalent to the :U modifier.
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INDIRECT= ${NESTED_UNDEF} ${NESTED_DEF}
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NESTED_DEF= nested-defined
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# Since NESTED_UNDEF is not controllable at this point, it must not generate
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# an error message, and it doesn't do so, since 2020-09-14.
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.if !${INDIRECT}
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. error
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.endif
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