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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
98 lines
3.5 KiB
Makefile
98 lines
3.5 KiB
Makefile
# $NetBSD: varmod-ifelse.mk,v 1.6 2020/11/12 00:29:55 rillig Exp $
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#
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# Tests for the ${cond:?then:else} variable modifier, which evaluates either
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# the then-expression or the else-expression, depending on the condition.
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#
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# The modifier was added on 1998-04-01.
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#
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# Until 2015-10-11, the modifier always evaluated both the "then" and the
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# "else" expressions.
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# TODO: Implementation
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# The variable name of the expression is expanded and then taken as the
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# condition. In this case it becomes:
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#
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# variable expression == "variable expression"
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#
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# This confuses the parser, which expects an operator instead of the bare
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# word "expression". If the name were expanded lazily, everything would be
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# fine since the condition would be:
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#
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# ${:Uvariable expression} == "literal"
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#
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# Evaluating the variable name lazily would require additional code in
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# Var_Parse and ParseVarname, it would be more useful and predictable
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# though.
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.if ${${:Uvariable expression} == "literal":?bad:bad}
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. error
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.else
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. error
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.endif
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# In a variable assignment, undefined variables are not an error.
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# Because of the early expansion, the whole condition evaluates to
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# ' == ""' though, which cannot be parsed because the left-hand side looks
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# empty.
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COND:= ${${UNDEF} == "":?bad-assign:bad-assign}
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# In a condition, undefined variables generate a "Malformed conditional"
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# error. That error message is wrong though. In lint mode, the correct
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# "Undefined variable" error message is generated.
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# The difference to the ':=' variable assignment is the additional
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# "Malformed conditional" error message.
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.if ${${UNDEF} == "":?bad-cond:bad-cond}
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. error
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.else
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. error
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.endif
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# When the :? is parsed, it is greedy. The else branch spans all the
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# text, up until the closing character '}', even if the text looks like
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# another modifier.
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.if ${1:?then:else:Q} != "then"
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. error
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.endif
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.if ${0:?then:else:Q} != "else:Q"
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. error
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.endif
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# This line generates 2 error messages. The first comes from evaluating the
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# malformed conditional "1 == == 2", which is reported as "Bad conditional
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# expression" by ApplyModifier_IfElse. The variable expression containing that
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# conditional therefore returns a parse error from Var_Parse, and this parse
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# error propagates to CondEvalExpression, where the "Malformed conditional"
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# comes from.
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.if ${1 == == 2:?yes:no} != ""
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. error
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.else
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. error
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.endif
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# If the "Bad conditional expression" appears in a quoted string literal, the
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# error message "Malformed conditional" is not printed, leaving only the "Bad
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# conditional expression".
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#
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# XXX: The left-hand side is enclosed in quotes. This results in Var_Parse
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# being called without VARE_UNDEFERR being set. When ApplyModifier_IfElse
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# returns AMR_CLEANUP as result, Var_Parse returns varUndefined since the
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# value of the variable expression is still undefined. CondParser_String is
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# then supposed to do proper error handling, but since varUndefined is local
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# to var.c, it cannot distinguish this return value from an ordinary empty
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# string. The left-hand side of the comparison is therefore just an empty
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# string, which is obviously equal to the empty string on the right-hand side.
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#
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# XXX: The debug log for -dc shows a comparison between 1.0 and 0.0. The
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# condition should be detected as being malformed before any comparison is
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# done since there is no well-formed comparison in the condition at all.
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.MAKEFLAGS: -dc
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.if "${1 == == 2:?yes:no}" != ""
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. error
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.else
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. warning Oops, the parse error should have been propagated.
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.endif
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.MAKEFLAGS: -d0
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all:
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@:;
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