mirror of
git://git.sv.gnu.org/autoconf
synced 2025-02-11 13:51:04 +08:00
0a0a337886
Several of the most commonly used Autoconf macros (starting with AC_CHECK_FUNCS and AC_CHECK_HEADERS) take a whitespace-separated list of symbols as their primary argument. It would abstractly be best if this list were _not_ subject to M4 macro expansion, in case there’s a collision between a M4 macro name and something to be looked for. However, we have historically not been careful about this, and there’s been reports of configure scripts using ‘dnl’ to write comments inside the list. The AS_LITERAL_IF optimizations added to AC_CHECK_FUNCS and AC_CHECK_HEADERS since 2.69 broke some of those scripts with bizarre shell syntax errors. Also, the macro expansion behavior is not consistent among all of the macros that take whitespace-separated lists, nor is it consistent between autoconf and autoheader. Address this by introducing a new m4sugar macro, currently called ‘m4_validate_w’ (I’m open to suggestions for better names). Here’s its documentation comment: | m4_validate_w(STRING): Expands into m4_normalize(m4_expand([STRING])), | but if that is not the same as just m4_normalize([STRING]), | issue a warning. The text of the warning is | configure.ac:N: warning: whitespace-separated-list contains macros; | configure.ac:N: in a future version of Autoconf they will not be expanded If the unexpanded form of the string contains the token ‘dnl’ then there’s an additional line: | configure.ac:N: note: ‘dnl’ is a macro All of the public macros that take a whitespace-separated list of symbols are changed to pass that argument through m4_validate_w before doing anything else with it, and the test suite is updated to verify consistent behavior for every last one of them. This addresses Savannah issues #110210 and #110211, and the harmless but annoying autoheader behavior described at https://lists.gnu.org/archive/html/bug-autoconf/2018-02/msg00005.html . In order to avoid expanding relatively expensive m4sugar macros multiple times per top-level macro invocation, several of the affected Autoconf macros are restructured along the same lines as I did for AC_REPLACE_FUNCS in the previous patch. * lib/m4sugar/m4sugar.m4 (m4_validate_w): New macro. * lib/autoconf/functions.m4 (AC_CHECK_FUNCS, AC_CHECK_FUNCS_ONCE) (AC_REPLACE_FUNCS) * lib/autoconf/general.m4 (AC_CONFIG_MACRO_DIRS, AC_CHECK_FILES) * lib/autoconf/headers.m4 (AC_CHECK_HEADERS, AC_CHECK_HEADERS_ONCE) * lib/autoconf/status.m4 (AC_CONFIG_SUBDIRS): Pass $1 through m4_validate_w before use. * lib/autoconf/headers.m4 (AC_CHECK_HEADERS): Refactor with helpers _AC_CHECK_HEADERS_ONE_U, _AC_CHECK_HEADERS_ONE_S, _AC_CHECK_HEADERS_ONE_C. (AC_CHECK_HEADERS_ONCE): Eliminate _AC_CHECK_HEADERS_ONCE. (AC_CHECK_INCLUDES_DEFAULT): Don’t use _AC_CHECK_HEADERS_ONCE. * lib/autoconf/functions.m4 (AC_CHECK_FUNCS): Refactor with helpers _AC_CHECK_FUNCS_ONE_U, _AC_CHECK_FUNCS_ONE_S, _AC_CHECK_FUNCS_ONE_C. * lib/autoconf/status.m4 (_AC_CONFIG_SUBDIRS): No need to use m4_normalize. * tests/semantics.at: Add tests for expansion of M4 macros in whitespace-separated list arguments to all of the above. |
||
|---|---|---|
| .. | ||
| autoconf | ||
| Autom4te | ||
| autoscan | ||
| autotest | ||
| emacs | ||
| m4sugar | ||
| autom4te.in | ||
| freeze.mk | ||
| local.mk | ||