Makefile: make USE_LIBPCRE=YesPlease mean v2, not v1

Change the USE_LIBPCRE flag from being an alias for USE_LIBPCRE1 to
being an alias for USE_LIBPCRE2.

When support for v2 was added in my 94da919 ("grep: add support for
PCRE v2", 2017-06-01) the existing USE_LIBPCRE flag was left as
meaning v1, with a note that this would likely change in a future
release. That optional support for v2 first made it into Git version
2.14.0.

The PCRE v2 support has been shown to be stable, and the upstream PCRE
project is highly encouraging downstream users to move to v2, so it
makes sense to give packagers of Git who haven't heard the news about
PCRE v2 a further nudge to move to v2.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

Makefile

@@ -29,10 +29,10 @@ all::
 # Perl-compatible regular expressions instead of standard or extended
 # POSIX regular expressions.
 #
-# Currently USE_LIBPCRE is a synonym for USE_LIBPCRE1, define
-# USE_LIBPCRE2 instead if you'd like to use version 2 of the PCRE
-# library. The USE_LIBPCRE flag will likely be changed to mean v2 by
-# default in future releases.
+# USE_LIBPCRE is a synonym for USE_LIBPCRE2, define USE_LIBPCRE1
+# instead if you'd like to use the legacy version 1 of the PCRE
+# library. Support for version 1 will likely be removed in some future
+# release of Git, as upstream has all but abandoned it.
 #
 # When using USE_LIBPCRE1, define NO_LIBPCRE1_JIT if the PCRE v1
 # library is compiled without --enable-jit. We will auto-detect
@@ -1164,13 +1164,18 @@ ifdef NO_LIBGEN_H
 	COMPAT_OBJS += compat/basename.o
 endif
 
-USE_LIBPCRE1 ?= $(USE_LIBPCRE)
+USE_LIBPCRE2 ?= $(USE_LIBPCRE)
 
-ifneq (,$(USE_LIBPCRE1))
-	ifdef USE_LIBPCRE2
-$(error Only set USE_LIBPCRE1 (or its alias USE_LIBPCRE) or USE_LIBPCRE2, not both!)
+ifneq (,$(USE_LIBPCRE2))
+	ifdef USE_LIBPCRE1
+$(error Only set USE_LIBPCRE2 (or its alias USE_LIBPCRE) or USE_LIBPCRE1, not both!)
 	endif
 
+	BASIC_CFLAGS += -DUSE_LIBPCRE2
+	EXTLIBS += -lpcre2-8
+endif
+
+ifdef USE_LIBPCRE1
 	BASIC_CFLAGS += -DUSE_LIBPCRE1
 	EXTLIBS += -lpcre
 
@@ -1179,11 +1184,6 @@ ifdef NO_LIBPCRE1_JIT
 endif
 endif
 
-ifdef USE_LIBPCRE2
-	BASIC_CFLAGS += -DUSE_LIBPCRE2
-	EXTLIBS += -lpcre2-8
-endif
-
 ifdef LIBPCREDIR
 	BASIC_CFLAGS += -I$(LIBPCREDIR)/include
 	EXTLIBS += -L$(LIBPCREDIR)/$(lib) $(CC_LD_DYNPATH)$(LIBPCREDIR)/$(lib)

configure.ac

@@ -254,36 +254,32 @@ GIT_PARSE_WITH([openssl]))
 # Perl-compatible regular expressions instead of standard or extended
 # POSIX regular expressions.
 #
-# Currently USE_LIBPCRE is a synonym for USE_LIBPCRE1, define
-# USE_LIBPCRE2 instead if you'd like to use version 2 of the PCRE
-# library. The USE_LIBPCRE flag will likely be changed to mean v2 by
-# default in future releases.
+# USE_LIBPCRE is a synonym for USE_LIBPCRE2, define USE_LIBPCRE1
+# instead if you'd like to use the legacy version 1 of the PCRE
+# library. Support for version 1 will likely be removed in some future
+# release of Git, as upstream has all but abandoned it.
 #
 # Define LIBPCREDIR=/foo/bar if your PCRE header and library files are in
 # /foo/bar/include and /foo/bar/lib directories.
 #
 AC_ARG_WITH(libpcre,
-AS_HELP_STRING([--with-libpcre],[synonym for --with-libpcre1]),
+AS_HELP_STRING([--with-libpcre],[synonym for --with-libpcre2]),
     if test "$withval" = "no"; then
-	USE_LIBPCRE1=
+	USE_LIBPCRE2=
     elif test "$withval" = "yes"; then
-	USE_LIBPCRE1=YesPlease
+	USE_LIBPCRE2=YesPlease
     else
-	USE_LIBPCRE1=YesPlease
+	USE_LIBPCRE2=YesPlease
 	LIBPCREDIR=$withval
 	AC_MSG_NOTICE([Setting LIBPCREDIR to $LIBPCREDIR])
-        dnl USE_LIBPCRE1 can still be modified below, so don't substitute
+        dnl USE_LIBPCRE2 can still be modified below, so don't substitute
         dnl it yet.
 	GIT_CONF_SUBST([LIBPCREDIR])
     fi)
 
 AC_ARG_WITH(libpcre1,
 AS_HELP_STRING([--with-libpcre1],[support Perl-compatible regexes via libpcre1 (default is NO)])
 AS_HELP_STRING([],           [ARG can be also prefix for libpcre library and headers]),
-    if test -n "$USE_LIBPCRE1"; then
-        AC_MSG_ERROR([Only supply one of --with-libpcre or its synonym --with-libpcre1!])
-    fi
-
     if test "$withval" = "no"; then
 	USE_LIBPCRE1=
     elif test "$withval" = "yes"; then
@@ -300,6 +296,10 @@ AS_HELP_STRING([],           [ARG can be also prefix for libpcre library and hea
 AC_ARG_WITH(libpcre2,
 AS_HELP_STRING([--with-libpcre2],[support Perl-compatible regexes via libpcre2 (default is NO)])
 AS_HELP_STRING([],           [ARG can be also prefix for libpcre library and headers]),
+    if test -n "$USE_LIBPCRE2"; then
+        AC_MSG_ERROR([Only supply one of --with-libpcre or its synonym --with-libpcre2!])
+    fi
+
     if test -n "$USE_LIBPCRE1"; then
         AC_MSG_ERROR([Only supply one of --with-libpcre1 or --with-libpcre2!])
     fi