[PATCH] maint.mk: add per-line exclusions to prohibitions

[Eric Blake]

_sc_search_regexp would let you skip entire files, but not
individual lines, until now.  As proof that adding in a new
per-line regex exception mechanism is useful, I found three
syntax checks that were previously open-coded, only because
they had to exclude individual lines.

* maint.mk (_sc_search_regexp): Add $exclude parameter.
(sc_prohibit_strcmp, sc_unmarked_diagnostics)
(sc_const_long_option): Use it.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog    |    7 +++++++
 top/maint.mk |   38 +++++++++++++++++++++++---------------
 2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ddc7b54..4efec2f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2012-03-01  Eric Blake  <address@hidden>
+
+       maint.mk: add per-line exclusions to prohibitions
+       * maint.mk (_sc_search_regexp): Add $exclude parameter.
+       (sc_prohibit_strcmp, sc_unmarked_diagnostics)
+       (sc_const_long_option): Use it.
+
 2012-02-29  Eric Blake  <address@hidden>

        termios: fix pid_t always, not just for tcgetsid
diff --git a/top/maint.mk b/top/maint.mk
index ee721de..4b0f4b7 100644
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -178,6 +178,13 @@ syntax-check: $(local-check)
 #     Regular expression (ERE) denoting either a forbidden construct
 #     or a required construct.  Those arguments are exclusive.
 #
+#  exclude
+#
+#     Regular expression (ERE) denoting lines to ignore that matched
+#     a prohibit construct.  For example, this can be used to exclude
+#     comments that mention why the nearby code uses an alternative
+#     construct instead of the simpler prohibited construct.
+#
 #  in_vc_files | in_files
 #
 #     grep-E-style regexp denoting the files to check.  If no files
@@ -231,6 +238,9 @@ define _sc_search_regexp
    test -z "$$prohibit" && test -z "$$require"                         \
      && { msg='Should specify either prohibit or require'              \
           $(_sc_say_and_exit) } || :;                                  \
+   test -z "$$prohibit" && test -n "$$exclude"                         \
+     && { msg='Use of exclude requires a prohibit pattern'             \
+          $(_sc_say_and_exit) } || :;                                  \
    test -n "$$in_vc_files" && test -n "$$in_files"                     \
      && { msg='Cannot specify both in_vc_files and in_files'           \
           $(_sc_say_and_exit) } || :;                                  \
@@ -258,6 +268,7 @@ define _sc_search_regexp
    if test -n "$$files"; then                                          \
      if test -n "$$prohibit"; then                                     \
        grep $$with_grep_options $(_ignore_case) -nE "$$prohibit" $$files \
+         | grep -vE "$${exclude-^$$}"                                  \
          && { msg="$$halt" $(_sc_say_and_exit) } || :;                 \
      else                                                              \
        grep $$with_grep_options $(_ignore_case) -LE "$$require" $$files \
@@ -305,11 +316,10 @@ sc_prohibit_atoi_atof:
 # Use STREQ rather than comparing strcmp == 0, or != 0.
 sp_ = strcmp *\(.+\)
 sc_prohibit_strcmp:
-       @grep -nE '! *strcmp *\(|\<$(sp_) *[!=]=|[!=]= *$(sp_)'         \
-           $$($(VC_LIST_EXCEPT))                                       \
-         | grep -vE ':# *define STRN?EQ\(' &&                          \
-         { echo '$(ME): replace strcmp calls above with STREQ/STRNEQ'  \
-               1>&2; exit 1; } || :
+       @prohibit='! *strcmp *\(|\<$(sp_) *[!=]=|[!=]= *$(sp_)'         \
+       exclude=':# *define STRN?EQ\('                                  \
+       halt='$(ME): replace strcmp calls above with STREQ/STRNEQ'      \
+         $(_sc_search_regexp)

 # Pass EXIT_*, not number, to usage, exit, and error (when exiting)
 # Convert all uses automatically, via these two commands:
@@ -709,12 +719,10 @@ _gl_translatable_diag_func_re ?= error
 # Look for diagnostics that aren't marked for translation.
 # This won't find any for which error's format string is on a separate line.
 sc_unmarked_diagnostics:
-       @grep -nE                                                       \
-           '\<$(_gl_translatable_diag_func_re) *\([^"]*"[^"]*[a-z]{3}' \
-               $$($(VC_LIST_EXCEPT))                                   \
-         | grep -Ev '(_|ngettext ?)\(' &&                              \
-         { echo '$(ME): found unmarked diagnostic(s)' 1>&2;            \
-           exit 1; } || :
+       @prohibit='\<$(_gl_translatable_diag_func_re) *\([^"]*"[^"]*[a-z]{3}' \
+       exclude='(_|ngettext ?)\('                                      \
+       halt='$(ME): found unmarked diagnostic(s)'                      \
+         $(_sc_search_regexp)

 # Avoid useless parentheses like those in this example:
 # #if defined (SYMBOL) || defined (SYM2)
@@ -975,10 +983,10 @@ sc_redundant_const:
          $(_sc_search_regexp)

 sc_const_long_option:
-       @grep '^ *static.*struct option ' $$($(VC_LIST_EXCEPT))         \
-         | grep -Ev 'const struct option|struct option const' && {     \
-             echo 1>&2 '$(ME): add "const" to the above declarations'; \
-             exit 1; } || :
+       @prohibit='^ *static.*struct option '                           \
+       exclude='const struct option|struct option const'               \
+       halt='$(ME): add "const" to the above declarations'             \
+         $(_sc_search_regexp)

 NEWS_hash =                                                            \
   $$(sed -n '/^\*.* $(PREV_VERSION_REGEXP) ([0-9-]*)/,$$p'             \
-- 
1.7.7.6