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authorKyle J. McKay <mackyle@gmail.com>2015-01-11 12:09:22 -0800
committerJunio C Hamano <gitster@pobox.com>2015-01-12 11:10:19 -0800
commit290c8e7a3fe182ff64c3e6b76fbbbc6dcff4727c (patch)
tree8d36303d98f732f848715d2f125a0e2d89f98f5a
parent7ba46269a04de20032bd2dd614be6290cd65caab (diff)
downloadgit-290c8e7a3fe182ff64c3e6b76fbbbc6dcff4727c.tar.gz
git-290c8e7a3fe182ff64c3e6b76fbbbc6dcff4727c.tar.xz
gettext.h: add parentheses around N_ expansion if supported
The gettext N_ macro is used to mark strings for translation without actually translating them. At runtime the string is expected to be passed to the gettext API for translation. If two N_ macro invocations appear next to each other with only whitespace (or nothing at all) between them, the two separate strings will be marked for translation, but the preprocessor will then silently combine the strings into one and at runtime the string passed to gettext will not match the strings that were translated so no translation will actually occur. Avoid this by adding parentheses around the expansion of the N_ macro so that instead of ending up with two adjacent strings that are then combined by the preprocessor, two adjacent strings surrounded by parentheses result instead which causes a compile error so the mistake can be quickly found and corrected. However, since these string literals are typically assigned to static variables and not all compilers support parenthesized string literal assignments, allow this to be controlled by the Makefile with the default only enabled when the compiler is known to support the syntax. For now only __GNUC__ enables this by default which covers both gcc and clang which should result in early detection of any adjacent N_ macros. Although the necessary tests make the affected files a bit less elegant, the benefit of avoiding propagation of a translation- marking error to all the translation teams thus creating extra work for them when the error is eventually detected and fixed would seem to outweigh the minor inelegance the additional configuration tests introduce. Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Kyle J. McKay <mackyle@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--Makefile17
-rw-r--r--gettext.h24
-rw-r--r--git-compat-util.h4
3 files changed, 45 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index 7482a4dba..be740010e 100644
--- a/Makefile
+++ b/Makefile
@@ -339,6 +339,15 @@ all::
# return NULL when it receives a bogus time_t.
#
# Define HAVE_CLOCK_GETTIME if your platform has clock_gettime in librt.
+#
+# Define USE_PARENS_AROUND_GETTEXT_N to "yes" if your compiler happily
+# compiles the following initialization:
+#
+# static const char s[] = ("FOO");
+#
+# and define it to "no" if you need to remove the parentheses () around the
+# constant. The default is "auto", which means to use parentheses if your
+# compiler is detected to support it.
GIT-VERSION-FILE: FORCE
@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -946,6 +955,14 @@ ifneq (,$(SOCKLEN_T))
BASIC_CFLAGS += -Dsocklen_t=$(SOCKLEN_T)
endif
+ifeq (yes,$(USE_PARENS_AROUND_GETTEXT_N))
+ BASIC_CFLAGS += -DUSE_PARENS_AROUND_GETTEXT_N=1
+else
+ifeq (no,$(USE_PARENS_AROUND_GETTEXT_N))
+ BASIC_CFLAGS += -DUSE_PARENS_AROUND_GETTEXT_N=0
+endif
+endif
+
ifeq ($(uname_S),Darwin)
ifndef NO_FINK
ifeq ($(shell test -d /sw/lib && echo y),y)
diff --git a/gettext.h b/gettext.h
index 7671d09d0..dc1722dd4 100644
--- a/gettext.h
+++ b/gettext.h
@@ -63,6 +63,30 @@ const char *Q_(const char *msgid, const char *plu, unsigned long n)
}
/* Mark msgid for translation but do not translate it. */
+#if !USE_PARENS_AROUND_GETTEXT_N
#define N_(msgid) msgid
+#else
+/*
+ * Strictly speaking, this will lead to invalid C when
+ * used this way:
+ * static const char s[] = N_("FOO");
+ * which will expand to
+ * static const char s[] = ("FOO");
+ * and in valid C, the initializer on the right hand side must
+ * be without the parentheses. But many compilers do accept it
+ * as a language extension and it will allow us to catch mistakes
+ * like:
+ * static const char *msgs[] = {
+ * N_("one")
+ * N_("two"),
+ * N_("three"),
+ * NULL
+ * };
+ * (notice the missing comma on one of the lines) by forcing
+ * a compilation error, because parenthesised ("one") ("two")
+ * will not get silently turned into ("onetwo").
+ */
+#define N_(msgid) (msgid)
+#endif
#endif
diff --git a/git-compat-util.h b/git-compat-util.h
index 400e92108..572664371 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -828,4 +828,8 @@ struct tm *git_gmtime_r(const time_t *, struct tm *);
#define gmtime_r git_gmtime_r
#endif
+#if !defined(USE_PARENS_AROUND_GETTEXT_N) && defined(__GNUC__)
+#define USE_PARENS_AROUND_GETTEXT_N 1
+#endif
+
#endif