Fix some issues found by Coverity Scan

Some of them are just brain dead code, some are potential bugs.

source/blender/editors/animation/anim_channels_edit.c

@@ -3055,7 +3055,7 @@ static bool select_anim_channel_keys(bAnimContext *ac, int channel_index, bool e
 	ANIM_animdata_freelist(&anim_data);
 
 	/* F-Curve may not have any keyframes */
-	if (fcu->bezt) {
+	if (fcu && fcu->bezt) {
 		BezTriple *bezt;
 
 		if (!extend) {

source/blender/editors/interface/interface_handlers.c

@@ -9077,6 +9077,9 @@ static int ui_handle_menu_return_submenu(bContext *C, const wmEvent *event, uiPo
 	block = ar->uiblocks.first;
 
 	but = ui_but_find_active_in_region(ar);
+
+	BLI_assert(but);
+
 	data = but->active;
 	submenu = data->menu;
 

source/blender/editors/interface/interface_panel.c

@@ -1215,7 +1215,6 @@ static void ui_panel_drag_collapse(bContext *C, uiPanelDragCollapseHandle *dragc
 		rect.ymin = rect.ymax;
 		rect.ymax = rect.ymin + PNL_HEADER;
 		if (pa->flag & PNL_CLOSEDX) {
-			rect.xmin = rect.xmin;
 			rect.xmax = rect.xmin + PNL_HEADER;
 		}
 

source/blender/editors/interface/interface_regions.c

@@ -1427,7 +1427,8 @@ static void ui_block_position(wmWindow *window, ARegion *butregion, uiBut *but,
 		if (down || top) {
 			if (dir1 == UI_DIR_UP   && top == 0)  dir1 = UI_DIR_DOWN;
 			if (dir1 == UI_DIR_DOWN && down == 0) dir1 = UI_DIR_UP;
-			if (dir2 == UI_DIR_UP   && top == 0)  dir2 = UI_DIR_DOWN;
+			/* dir2 is never set to UI_DIR_UP here */
+//			if (dir2 == UI_DIR_UP   && top == 0)  dir2 = UI_DIR_DOWN;
 			if (dir2 == UI_DIR_DOWN && down == 0) dir2 = UI_DIR_UP;
 		}
 

source/blender/editors/interface/interface_style.c

@@ -323,10 +323,14 @@ void UI_fontstyle_draw_simple_backdrop(
 /* XXX: read a style configure */
 uiStyle *UI_style_get(void)
 {
+#if 0
 	uiStyle *style = NULL;
 	/* offset is two struct uiStyle pointers */
-	/* style = BLI_findstring(&U.uistyles, "Unifont Style", sizeof(style) * 2) */;
+	style = BLI_findstring(&U.uistyles, "Unifont Style", sizeof(style) * 2);
 	return (style != NULL) ? style : U.uistyles.first;
+#else
+	return U.uistyles.first;
+#endif
 }
 
 /* for drawing, scaled with DPI setting */

source/blender/editors/interface/interface_templates.c

@@ -3214,7 +3214,6 @@ void uiTemplateList(
 
 			/* add scrollbar */
 			if (len > layoutdata.visual_items) {
-				col = uiLayoutColumn(row, false);
 				uiDefButI(block, UI_BTYPE_SCROLL, 0, "", 0, 0, UI_UNIT_X * 0.75, UI_UNIT_Y * dyn_data->visual_height,
 				          &ui_list->list_scroll, 0, dyn_data->height - dyn_data->visual_height,
 				          dyn_data->visual_height, 0, "");

source/blender/editors/screen/area.c

@@ -1263,16 +1263,22 @@ static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti
 	if (ar->flag & (RGN_FLAG_HIDDEN | RGN_FLAG_TOO_SMALL)) {
 		ar->winrct = *remainder;
 		
-		if (alignment == RGN_ALIGN_TOP)
-			ar->winrct.ymin = ar->winrct.ymax;
-		else if (alignment == RGN_ALIGN_BOTTOM)
-			ar->winrct.ymax = ar->winrct.ymin;
-		else if (alignment == RGN_ALIGN_RIGHT)
-			ar->winrct.xmin = ar->winrct.xmax;
-		else if (alignment == RGN_ALIGN_LEFT)
-			ar->winrct.xmax = ar->winrct.xmin;
-		else /* prevent winrct to be valid */
-			ar->winrct.xmax = ar->winrct.xmin;
+		switch (alignment) {
+			case RGN_ALIGN_TOP:
+				ar->winrct.ymin = ar->winrct.ymax;
+				break;
+			case RGN_ALIGN_BOTTOM:
+				ar->winrct.ymax = ar->winrct.ymin;
+				break;
+			case RGN_ALIGN_RIGHT:
+				ar->winrct.xmin = ar->winrct.xmax;
+				break;
+			case RGN_ALIGN_LEFT:
+			default:
+				/* prevent winrct to be valid */
+				ar->winrct.xmax = ar->winrct.xmin;
+				break;
+		}
 	}
 
 	/* restore prev-split exception */
@@ -2161,7 +2167,7 @@ static void metadata_draw_imbuf(ImBuf *ibuf, rctf rect, int fontid, const bool i
 
 static float metadata_box_height_get(ImBuf *ibuf, int fontid, const bool is_top)
 {
-	char str[MAX_METADATA_STR];
+	char str[MAX_METADATA_STR] = "";
 	short i, count = 0;
 	const float height = BLF_height_max(fontid) + 0.1f * U.widget_unit;
 

source/blender/editors/screen/screen_edit.c

@@ -1748,7 +1748,9 @@ ScrArea *ED_screen_full_newspace(bContext *C, ScrArea *sa, int type)
 			newsa = sa;
 		}
 	}
-	
+
+	BLI_assert(newsa);
+
 	if (sa && (sa->spacetype != type)) {
 		newsa->flag |= AREA_FLAG_TEMP_TYPE;
 	}

source/blender/editors/space_file/filelist.c

@@ -1234,7 +1234,7 @@ static void filelist_from_main(struct FileList *filelist)
 
 		files = filelist->filelist;
 
-		if (!filelist->filter_data.hide_parent) {
+		if (files && !filelist->filter_data.hide_parent) {
 			memset(&(filelist->filelist[0]), 0, sizeof(struct direntry));
 			filelist->filelist[0].relname = BLI_strdup(FILENAME_PARENT);
 			filelist->filelist[0].type |= S_IFDIR;
@@ -1246,7 +1246,7 @@ static void filelist_from_main(struct FileList *filelist)
 		for (id = lb->first; id; id = id->next) {
 			ok = 1;
 			if (ok) {
-				if (!filelist->filter_data.hide_dot || id->name[2] != '.') {
+				if (files && (!filelist->filter_data.hide_dot || id->name[2] != '.')) {
 					memset(files, 0, sizeof(struct direntry));
 					if (id->lib == NULL) {
 						files->relname = BLI_strdup(id->name + 2);

source/blender/editors/space_view3d/view3d_draw.c

@@ -3262,6 +3262,9 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Scene *scene, View3D *v3d, ARegion *ar, in
 	GPUOffScreen *ofs;
 	bool draw_sky = (alpha_mode == R_ADDSKY) && v3d && (v3d->flag3 & V3D_SHOW_WORLD);
 
+	if (UNLIKELY(v3d == NULL))
+		return NULL;
+
 	/* state changes make normal drawing go weird otherwise */
 	glPushAttrib(GL_LIGHTING_BIT);
 

source/blender/editors/transform/transform_manipulator.c

@@ -1056,8 +1056,6 @@ static void draw_manipulator_rotate(
 			glRotatef(90.0, 1.0, 0.0, 0.0);
 			postOrtho(ortho);
 		}
-
-		if (arcs) glDisable(GL_CLIP_PLANE0);
 	}
 	// donut arcs
 	if (arcs) {

source/blender/windowmanager/intern/wm_event_system.c

@@ -1173,7 +1173,7 @@ static int wm_operator_call_internal(bContext *C, wmOperatorType *ot, PointerRNA
 	CTX_wm_operator_poll_msg_set(C, NULL);
 
 	/* dummie test */
-	if (ot && C) {
+	if (ot) {
 		wmWindow *window = CTX_wm_window(C);
 
 		switch (context) {
@@ -2434,7 +2434,7 @@ void wm_event_do_handlers(bContext *C)
 
 				/* XXX hrmf, this gives reliable previous mouse coord for area change, feels bad? 
 				 * doing it on ghost queue gives errors when mousemoves go over area borders */
-				if (doit && win->screen && win->screen->subwinactive != win->screen->mainwin) {
+				if (doit && win->screen->subwinactive != win->screen->mainwin) {
 					win->eventstate->prevx = event->x;
 					win->eventstate->prevy = event->y;
 					//printf("win->eventstate->prev = %d %d\n", event->x, event->y);

source/blender/windowmanager/intern/wm_keymap.c

@@ -546,7 +546,7 @@ static void wm_keymap_diff(wmKeyMap *diff_km, wmKeyMap *from_km, wmKeyMap *to_km
 		if (to_kmi) {
 			orig_kmi = WM_keymap_item_find_id(orig_km, kmi->id);
 
-			if (!orig_kmi)
+			if (!orig_kmi && addon_km)
 				orig_kmi = wm_keymap_find_item_equals(addon_km, kmi);
 
 			if (orig_kmi) {