From 1ec56844387ed910b7e87bae186b58cc22cc317a Mon Sep 17 00:00:00 2001
From: Craig Barnes <craigbarnes@protonmail.com>
Date: Tue, 9 Feb 2021 13:52:33 +0000
Subject: [PATCH 1/4] Convert some uses of xassert(false) to BUG("some error
 message")

---
 config.c   |  2 +-
 fdm.c      |  2 +-
 input.c    |  2 +-
 render.c   |  5 ++---
 terminal.c | 11 +++++------
 5 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/config.c b/config.c
index 04d563eb..56acb0cf 100644
--- a/config.c
+++ b/config.c
@@ -1230,7 +1230,7 @@ argv_compare(char *const *argv1, char *const *argv2)
             return ret;
     }
 
-    xassert(false);
+    BUG("unexpected loop break");
     return 1;
 }
 
diff --git a/fdm.c b/fdm.c
index 3394f10c..ef956450 100644
--- a/fdm.c
+++ b/fdm.c
@@ -251,7 +251,7 @@ hook_priority_to_list(struct fdm *fdm, enum fdm_hook_priority priority)
     case FDM_HOOK_PRIORITY_HIGH:   return &fdm->hooks_high;
     }
 
-    xassert(false);
+    BUG("unhandled priority type");
     return NULL;
 }
 
diff --git a/input.c b/input.c
index 79368270..ad3934b6 100644
--- a/input.c
+++ b/input.c
@@ -209,7 +209,7 @@ execute_binding(struct seat *seat, struct terminal *term,
             break;
 
         default:
-            xassert(false);
+            BUG("Unhandled action type");
             success = false;
             break;
         }
diff --git a/render.c b/render.c
index 71d54f4c..99869c2c 100644
--- a/render.c
+++ b/render.c
@@ -1367,11 +1367,10 @@ get_csd_data(const struct terminal *term, enum csd_surface surf_idx)
     case CSD_SURF_CLOSE:    return (struct csd_data){term->width - 1 * button_width, 0, button_close_width,    title_height};
 
     case CSD_SURF_COUNT:
-        xassert(false);
-        return (struct csd_data){0};
+        break;
     }
 
-    xassert(false);
+    BUG("Invalid csd_surface type");
     return (struct csd_data){0};
 }
 
diff --git a/terminal.c b/terminal.c
index 8e1e1841..c080c0c4 100644
--- a/terminal.c
+++ b/terminal.c
@@ -97,8 +97,7 @@ data_to_slave(struct terminal *term, const void *data, size_t len,
         return false;
     }
 
-    /* Shouldn't get here */
-    xassert(false);
+    BUG("Unexpected async_write() return value");
     return false;
 }
 
@@ -1931,7 +1930,7 @@ term_row_rel_to_abs(const struct terminal *term, int row)
         return min(row + term->scroll_region.start, term->scroll_region.end - 1);
     }
 
-    xassert(false);
+    BUG("Invalid cursor_origin value");
     return -1;
 }
 
@@ -2483,7 +2482,7 @@ term_mouse_down(struct terminal *term, int button, int row, int col,
 
     case MOUSE_X10:
         /* Never enabled */
-        xassert(false && "unimplemented");
+        BUG("X10 mouse mode not implemented");
         break;
     }
 }
@@ -2525,7 +2524,7 @@ term_mouse_up(struct terminal *term, int button, int row, int col,
 
     case MOUSE_X10:
         /* Never enabled */
-        xassert(false && "unimplemented");
+        BUG("X10 mouse mode not implemented");
         break;
     }
 }
@@ -2572,7 +2571,7 @@ term_mouse_motion(struct terminal *term, int button, int row, int col,
 
     case MOUSE_X10:
         /* Never enabled */
-        xassert(false && "unimplemented");
+        BUG("X10 mouse mode not implemented");
         break;
     }
 }

From 2f81a1d07c3828391bf1b5656a9143aaf3822089 Mon Sep 17 00:00:00 2001
From: Craig Barnes <craigbarnes@protonmail.com>
Date: Tue, 9 Feb 2021 15:16:19 +0000
Subject: [PATCH 2/4] Convert some more uses of xassert(false) to BUG("...")

---
 input.c  | 4 ++--
 render.c | 2 +-
 search.c | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/input.c b/input.c
index ad3934b6..944f1336 100644
--- a/input.c
+++ b/input.c
@@ -325,7 +325,7 @@ execute_binding(struct seat *seat, struct terminal *term,
         return true;
 
     case BIND_ACTION_COUNT:
-        xassert(false);
+        BUG("Invalid action type");
         return false;
     }
 
@@ -1150,7 +1150,7 @@ xcursor_for_csd_border(struct terminal *term, int x, int y)
     else if (term->active_surface == TERM_SURF_BORDER_TOP)    return XCURSOR_TOP_SIDE;
     else if (term->active_surface == TERM_SURF_BORDER_BOTTOM) return XCURSOR_BOTTOM_SIDE;
     else {
-        xassert(false);
+        BUG("Unreachable");
         return NULL;
     }
 }
diff --git a/render.c b/render.c
index 99869c2c..8cf7f29a 100644
--- a/render.c
+++ b/render.c
@@ -1669,7 +1669,7 @@ render_csd_button(struct terminal *term, enum csd_surface surf_idx)
         break;
 
     default:
-        xassert(false);
+        BUG("unhandled surface type: %u", (unsigned)surf_idx);
         break;
     }
 
diff --git a/search.c b/search.c
index 4fde8a92..d7939219 100644
--- a/search.c
+++ b/search.c
@@ -785,11 +785,11 @@ execute_binding(struct seat *seat, struct terminal *term,
         return true;
 
     case BIND_ACTION_SEARCH_COUNT:
-        xassert(false);
+        BUG("Invalid action type");
         return true;
     }
 
-    xassert(false);
+    BUG("Unhandled action type");
     return false;
 }
 

From 3c86af52c2a3e9352a88e969392575e55c3b6f74 Mon Sep 17 00:00:00 2001
From: Craig Barnes <craigbarnes@protonmail.com>
Date: Wed, 10 Feb 2021 09:01:51 +0000
Subject: [PATCH 3/4] Convert all but 2 remaining uses of xassert(false) to
 BUG("...")

---
 fdm.c       |  8 ++------
 input.c     |  4 ++--
 render.c    |  4 ++--
 selection.c | 13 ++++++-------
 4 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/fdm.c b/fdm.c
index ef956450..34d0fbff 100644
--- a/fdm.c
+++ b/fdm.c
@@ -105,16 +105,12 @@ fdm_add(struct fdm *fdm, int fd, int events, fdm_handler_t handler, void *data)
 #if defined(_DEBUG)
     int flags = fcntl(fd, F_GETFL);
     if (!(flags & O_NONBLOCK)) {
-        LOG_ERR("FD=%d is in blocking mode", fd);
-        xassert(false);
-        return false;
+        BUG("FD=%d is in blocking mode", fd);
     }
 
     tll_foreach(fdm->fds, it) {
         if (it->item->fd == fd) {
-            LOG_ERR("FD=%d already registered", fd);
-            xassert(false);
-            return false;
+            BUG("FD=%d already registered", fd);
         }
     }
 #endif
diff --git a/input.c b/input.c
index 944f1336..64ab2065 100644
--- a/input.c
+++ b/input.c
@@ -1225,7 +1225,7 @@ wl_pointer_enter(void *data, struct wl_pointer *wl_pointer,
         break;
 
     case TERM_SURF_NONE:
-        xassert(false);
+        BUG("Invalid surface type");
         break;
     }
 }
@@ -1806,7 +1806,7 @@ wl_pointer_button(void *data, struct wl_pointer *wl_pointer,
     }
 
     case TERM_SURF_NONE:
-        xassert(false);
+        BUG("Invalid surface type");
         break;
 
     }
diff --git a/render.c b/render.c
index 8cf7f29a..026f176f 100644
--- a/render.c
+++ b/render.c
@@ -1642,7 +1642,7 @@ render_csd_button(struct terminal *term, enum csd_surface surf_idx)
         break;
 
     default:
-        xassert(false);
+        BUG("unhandled surface type: %u", (unsigned)surf_idx);
         break;
     }
 
@@ -1878,7 +1878,7 @@ render_scrollback_position(struct terminal *term)
     int surf_top = 0;
     switch (term->conf->scrollback.indicator.position) {
     case SCROLLBACK_INDICATOR_POSITION_NONE:
-        xassert(false);
+        BUG("Invalid scrollback indicator position type");
         return;
 
     case SCROLLBACK_INDICATOR_POSITION_FIXED:
diff --git a/selection.c b/selection.c
index 90c6c392..cb625541 100644
--- a/selection.c
+++ b/selection.c
@@ -195,11 +195,10 @@ foreach_selected(
         return;
 
     case SELECTION_NONE:
-        xassert(false);
-        return;
+        break;
     }
 
-    xassert(false);
+    BUG("Invalid selection kind");
 }
 
 static bool
@@ -426,7 +425,7 @@ selection_start(struct terminal *term, int col, int row,
         break;
 
     case SELECTION_NONE:
-        xassert(false);
+        BUG("Invalid selection kind");
         break;
     }
 
@@ -728,7 +727,7 @@ selection_update(struct terminal *term, int col, int row)
         break;
 
     case SELECTION_NONE:
-        xassert(false);
+        BUG("Invalid selection kind");
         break;
     }
 
@@ -861,7 +860,7 @@ selection_extend_normal(struct terminal *term, int col, int row,
 
     case SELECTION_BLOCK:
     case SELECTION_NONE:
-        xassert(false);
+        BUG("Invalid selection kind in this context");
         break;
     }
 
@@ -963,7 +962,7 @@ selection_extend(struct seat *seat, struct terminal *term,
 
     switch (term->selection.kind) {
     case SELECTION_NONE:
-        xassert(false);
+        BUG("Invalid selection kind");
         return;
 
     case SELECTION_CHAR_WISE:

From 19a5f25b80f44e5440a444df8af443d0081e46bf Mon Sep 17 00:00:00 2001
From: Craig Barnes <craigbarnes@protonmail.com>
Date: Wed, 10 Feb 2021 09:18:50 +0000
Subject: [PATCH 4/4] Mark slave_exec() as "noreturn" and convert
 xassert(false) to BUG(...)

---
 slave.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/slave.c b/slave.c
index 29ad92f5..432e21ff 100644
--- a/slave.c
+++ b/slave.c
@@ -18,6 +18,7 @@
 #include "log.h"
 
 #include "debug.h"
+#include "macros.h"
 #include "terminal.h"
 #include "tokenize.h"
 #include "xmalloc.h"
@@ -143,7 +144,7 @@ emit_notifications(int fd, const user_notifications_t *notifications)
         emit_notifications_of_kind(fd, notifications, USER_NOTIFICATION_DEPRECATED);
 }
 
-static void
+static noreturn void
 slave_exec(int ptmx, char *argv[], int err_fd, bool login_shell,
            const user_notifications_t *notifications)
 {
@@ -316,7 +317,7 @@ slave_spawn(int ptmx, int argc, const char *cwd, char *const *argv,
             setenv("SHELL", shell_argv[0], 1);
 
         slave_exec(ptmx, shell_argv, fork_pipe[1], login_shell, notifications);
-        xassert(false);
+        BUG("Unexpected return from slave_exec()");
         break;
 
     default: {