From 7da1dd01e6ba959cab9b97480e2eacf16529fe60 Mon Sep 17 00:00:00 2001 From: Marcel Moolenaar Date: Wed, 15 Jan 2003 22:36:15 +0000 Subject: Change the handling of non-anchored global substitutions of the empty string from a silent implicit non-global substitution to a non-silent explicit fatal error. Archored substitutions are those containing '^' or '$'. The problem with changing the substitution to prevent an infinite number of matches is that it doesn't provide the necessary feedback to the user that there's a bug in the/a makefile. Reporting the bug without making the condition fatal makes the feedback mostly useless due to the way that make fails to prefix the error with program name, makefile file name and line number information. Note that global substitutions of the empty string anchored with '^' (start of string) or '$' (end of string) do not cause an infinite number of matches and are therefore not reported and hence are non- fatal. Suggested by: bde Tested with: buildworld --- usr.bin/make/var.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/usr.bin/make/var.c b/usr.bin/make/var.c index 32da4e860d2fc..3221bdd8ea84c 100644 --- a/usr.bin/make/var.c +++ b/usr.bin/make/var.c @@ -1350,15 +1350,16 @@ Var_Parse(char *str, GNode *ctxt, Boolean err, int *lengthPtr, Boolean *freePtr) } /* - * Replacing the empty string for something else when - * done globally causes an infinite loop. The only - * meaningful substitution of the empty string would - * be those anchored by '^' or '$'. Thus, we can - * safely turn the substitution into a non-global one - * if the LHS is the empty string. + * Global substitution of the empty string causes an + * infinite number of matches, unless anchored by '^' + * (start of string) or '$' (end of string). Catch the + * infinite substitution here. + * Note that flags can only contain the 3 bits we're + * interested in so we don't have to mask unrelated + * bits. We can test for equality. */ - if (pattern.leftLen == 0) - pattern.flags &= ~VAR_SUB_GLOBAL; + if (!pattern.leftLen && pattern.flags == VAR_SUB_GLOBAL) + Fatal("Global substitution of the empty string"); termc = *cp; newStr = VarModify(str, VarSubstitute, -- cgit v1.3