[groff] 02/02: Make our assert() C99-conformant.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 642353ef06b3c2b49f74b71e0d5ecdfa866fe3de
Author: G. Branden Robinson <address@hidden>
AuthorDate: Mon Apr 13 17:42:18 2020 +1000

    Make our assert() C99-conformant.
    
    groff has its own implementation of the standard C library's assert()
    macro.  It hasn't been updated since C89.  C99 requires that the
    diagnostic emitted by assert() contain the failing expression and name
    of the function in scope.
    
    * src/include/assert.h: Add additional pointer to const char arguments
      to do_assert() and assertion_failed() for function name and
      stringified expression.
      (assertion_failed): Update prototype.
      (do_assert): Accept 'func' and 'msg' parameters and pass them to
      assertion_failed().
      (assert): Update macro to collect '__func__' and stringify the expr
      parameter (as 'msg') and pass them do do_assert().
    * src/libs/libgroff/assert.cpp (assertion_failed): Rewrite diagnostic to
      more closely match GNU Coding Style format and also report function
      and failing expression.
    
    Example output:
        troff: ../src/roff/troff/input.cpp:2644: do_request(): assertion
        failed: '0 == "But first, here's a rotten old BBC programme."'
    
    We have no excuse to assert(0) ever again.  Express the invariant that
    has been violated.
---
 ChangeLog                    | 29 +++++++++++++++++++++++++++++
 src/include/assert.h         | 10 ++++++----
 src/libs/libgroff/assert.cpp |  7 ++++---
 3 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6b93e50..00fe35f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,34 @@
 2020-04-13  G. Branden Robinson <address@hidden>
 
+       Make our assert() C99-conformant.
+
+       groff has its own implementation of the standard C library's
+       assert() macro.  It hasn't been updated since C89.  C99 requires
+       that the diagnostic emitted by assert() contain the failing
+       expression and name of the function in scope.
+
+       * src/include/assert.h: Add additional pointer to const char
+       arguments to do_assert() and assertion_failed() for function
+       name and stringified expression.
+       (assertion_failed): Update prototype.
+       (do_assert): Accept 'func' and 'msg' parameters and pass them to
+       assertion_failed().
+       (assert): Update macro to collect '__func__' and stringify the
+       expr parameter (as 'msg') and pass them do do_assert().
+       * src/libs/libgroff/assert.cpp (assertion_failed): Rewrite
+       diagnostic to more closely match GNU Coding Style format and
+       also report function and failing expression.
+
+       Example output:
+               troff: ../src/roff/troff/input.cpp:2644: do_request():
+               assertion failed: '0 == "But first, here's a rotten old
+               BBC programme."'
+
+       We have no excuse to assert(0) ever again.  Express the
+       invariant that has been violated.
+
+2020-04-13  G. Branden Robinson <address@hidden>
+
        * src/roff/groff/tests/smoke-test_html_device.sh: Set
        LC_CTYPE=C.UTF-8 so that byte sequences in the pipelines are
        handled correctly.  Thanks to Bjarni Ingi Gislason for the
diff --git a/src/include/assert.h b/src/include/assert.h
index d717c98..581cf88 100644
--- a/src/include/assert.h
+++ b/src/include/assert.h
@@ -20,12 +20,13 @@ along with this program.  If not, see 
<http://www.gnu.org/licenses/>. */
 #ifndef ASSERT_H
 #define ASSERT_H
 
-void assertion_failed(int, const char *);
+void assertion_failed(int, const char *, const char *, const char *);
 
-inline void do_assert(int expr, int line, const char *file)
+inline void do_assert(int expr, int line, const char *file,
+                      const char *func, const char *msg)
 {
   if (!expr)
-    assertion_failed(line, file);
+    assertion_failed(line, file, func, msg);
 }
 #endif /* ASSERT_H */
 
@@ -34,5 +35,6 @@ inline void do_assert(int expr, int line, const char *file)
 #ifdef NDEBUG
 #define assert(ignore) /* as nothing */
 #else
-#define assert(expr) do_assert(expr, __LINE__, __FILE__)
+#define assert(expr) do_assert(expr, __LINE__, __FILE__, __func__, \
+                               #expr)
 #endif
diff --git a/src/libs/libgroff/assert.cpp b/src/libs/libgroff/assert.cpp
index aceed05..80a9946 100644
--- a/src/libs/libgroff/assert.cpp
+++ b/src/libs/libgroff/assert.cpp
@@ -22,12 +22,13 @@ along with this program.  If not, see 
<http://www.gnu.org/licenses/>. */
 
 extern "C" const char *program_name;
 
-void assertion_failed(int lineno, const char *filename)
+void assertion_failed(int lineno, const char *filename,
+                      const char *function, const char *msg)
 {
   if (program_name != 0)
     fprintf(stderr, "%s: ", program_name);
-  fprintf(stderr, "Failed assertion at line %d, file '%s'.\n",
-         lineno, filename);
+  fprintf(stderr, "%s:%d: %s(): assertion failed: '%s'\n", filename,
+         lineno, function, msg);
   fflush(stderr);
   abort();
 }