Fix -Wimplicit-fallthrough warnings (#2760)

* define FALLTHROUGH attribute statement macro and use it where needed * break switch cases where needed * CI: remove exempted compiler warning
OSGeo · Feb 14, 2023 · fedef50 · fedef50
1 parent 20bba91
commit fedef50
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Showing 10 changed files with 24 additions and 3 deletions.
diff --git a/.github/workflows/gcc.yml b/.github/workflows/gcc.yml
@@ -56,8 +56,6 @@ jobs:
         env:
           # TODO: -pedantic-errors here won't go through ./configure (with GNU C)
           CFLAGS: -std=${{ matrix.c }} -fPIC -Wall -Wextra
-            -Wno-error=implicit-fallthrough
           # TODO: -pedantic-errors here won't compile
           CXXFLAGS: -std=${{ matrix.cpp }} -fPIC -Wall -Wextra
-            -Wno-error=implicit-fallthrough
         run: .github/workflows/build_ubuntu-22.04.sh $HOME/install -Werror
diff --git a/display/d.labels/do_labels.c b/display/d.labels/do_labels.c
@@ -456,9 +456,11 @@ int scan_ref(char *buf)
     case 2:
         if (!(xmatch(word2) || ymatch(word2)))
             return 0;
+        FALLTHROUGH;
     case 1:
         if (xmatch(word1) || ymatch(word1))
             return 1;
+        FALLTHROUGH;
     default:
         return 0;
     }

diff --git a/imagery/i.atcorr/geomcond.cpp b/imagery/i.atcorr/geomcond.cpp
@@ -360,7 +360,8 @@ void GeomCond::parse()
     }
     case 4:
         campm = 1.0f; /* avhrr PM, case 4 must fall through to case 5 */
-    case 5:           /* avhrr PM and avhrr AM */
+        FALLTHROUGH;
+    case 5: /* avhrr PM and avhrr AM */
     {
         cin >> month;
         cin >> jday;

diff --git a/include/grass/gis.h b/include/grass/gis.h
@@ -49,6 +49,17 @@
 
 static const char *GRASS_copyright UNUSED = "GRASS GNU GPL licensed Software";
 
+/*!
+    \def FALLTHROUGH
+    \brief A macro for a fallthrough statement attribute
+ */
+#if (defined(__GNUC__) && __GNUC__ >= 7) || \
+    (defined(__clang__) && __clang_major__ >= 12)
+#define FALLTHROUGH __attribute__((__fallthrough__))
+#else
+#define FALLTHROUGH ((void)0)
+#endif
+
 /* GRASS version, GRASS date, git short hash of last change in GRASS headers
  * (and anything else in include)
  */

diff --git a/lib/bitmap/bitmap.c b/lib/bitmap/bitmap.c
@@ -152,6 +152,7 @@ int BM_set_mode(int mode, int size)
     case BM_FLAT:
     case BM_SPARSE:
         Mode = mode;
+        break;
     default:
         fprintf(stderr, "BM_set_mode:  Unknown mode: %d\n", mode);
         ret--;

diff --git a/lib/gmath/la.c b/lib/gmath/la.c
@@ -861,11 +861,13 @@ int G_matvect_extract_vector(mat_struct *mt, vtype vt, int indx)
     case RVEC: {
         mt->type = ROWVEC_;
         mt->v_indx = indx;
+        break;
     }
 
     case CVEC: {
         mt->type = COLVEC_;
         mt->v_indx = indx;
+        break;
     }
 
     default: {

diff --git a/lib/nviz/map_obj.c b/lib/nviz/map_obj.c
@@ -262,6 +262,7 @@ int Nviz_set_attr(int id, int type, int desc, int src, const char *str_value,
 
             break;
         }
+        FALLTHROUGH;
     default: {
         return 0;
     }

diff --git a/lib/ogsf/gvl_calc2.c b/lib/ogsf/gvl_calc2.c
@@ -374,6 +374,7 @@ int mc33_process_cube(int c_ndx, float *v)
         case 7:
             return OFFSET_T7_1 + m_config; /* 7.1 */
         };
+        break; /* will not reach this as previous switch is exhaustive */
 
     case 8:
         return OFFSET_T8 + m_config;
@@ -558,6 +559,7 @@ int mc33_process_cube(int c_ndx, float *v)
         default:
             fprintf(stderr, "Marching Cubes: Impossible case 13?\n");
         }
+        break; /* will not reach this as previous switch is exhaustive */
 
     case 14:
         return OFFSET_T14 + m_config;

diff --git a/ps/ps.map/scan_ref.c b/ps/ps.map/scan_ref.c
@@ -29,10 +29,12 @@ int scan_ref(char *buf, int *xref, int *yref)
         lowercase(word2);
         if (!(xmatch(word2, xref) || ymatch(word2, yref)))
             return 0;
+        FALLTHROUGH;
     case 1:
         lowercase(word1);
         if (xmatch(word1, xref) || ymatch(word1, yref))
             return 1;
+        FALLTHROUGH;
     default:
         return 0;
     }

diff --git a/vector/v.in.dxf/dxf_to_vect.c b/vector/v.in.dxf/dxf_to_vect.c
@@ -76,6 +76,7 @@ int dxf_to_vect(struct dxf_file *dxf, struct Map_info *Map)
                     case 30:
                         dxf_ext.B = atof(dxf_buf);
                         bounds++;
+                        FALLTHROUGH;
                     default:
                         break;
                     }