From 3224f8197f15c39168629f876c96c48da2de771c Mon Sep 17 00:00:00 2001
From: Sergey Sharybin <sergey.vfx@gmail.com>
Date: Sun, 13 Feb 2011 19:04:01 +0000
Subject: [PATCH] Fix #26072: ctrl+LMB on an empty curve make Blender crash

Crash was caused by keeping active segment index even when this
segment had been deleted. Fixed this and also changed behaviour
of creating new CV for case nothing is selected: new segment with
BEZIER type would be created.
---
 source/blender/editors/curve/editcurve.c | 33 ++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/source/blender/editors/curve/editcurve.c b/source/blender/editors/curve/editcurve.c
index 84c6bfaf55b..0f6b88554e1 100644
--- a/source/blender/editors/curve/editcurve.c
+++ b/source/blender/editors/curve/editcurve.c
@@ -4403,8 +4403,20 @@ static int addvert_Nurb(bContext *C, short mode, float location[3])
 	findselectedNurbvert(&editnurb->nurbs, &nu, &bezt, &bp);
 
 	if ((nu == NULL) || (nu->type==CU_BEZIER && bezt==NULL) || (nu->type!=CU_BEZIER && bp==NULL)) {
-		if(cu->actnu >= 0 && mode!='e') {
-			nu= BLI_findlink(&editnurb->nurbs, cu->actnu);
+		if(mode!='e') {
+			if(cu->actnu >= 0) nu= BLI_findlink(&editnurb->nurbs, cu->actnu);
+			else {
+				/* no selected sement -- create new one which is BEZIER tpye
+				   type couldn't be determined from Curve bt could be changed
+				   in the future, so shouldn't make much headache */
+
+				nu= MEM_callocN(sizeof(Nurb), "addvert_Nurb nu");
+				nu->type= CU_BEZIER;
+				nu->resolu= cu->resolu;
+				nu->flag |= CU_SMOOTH;
+
+				BLI_addtail(&editnurb->nurbs, nu);
+			}
 
 			if(nu->type==CU_BEZIER) {
 				newbezt= (BezTriple*)MEM_callocN(sizeof(BezTriple), "addvert_Nurb");
@@ -5615,6 +5627,7 @@ static int delete_exec(bContext *C, wmOperator *op)
 	BezTriple *bezt, *bezt1, *bezt2;
 	BPoint *bp, *bp1, *bp2;
 	int a, cut= 0, type= RNA_enum_get(op->ptr, "type");
+	int nuindex= 0;
 
 	if(obedit->type==OB_SURF) {
 		if(type==0) {
@@ -5649,6 +5662,9 @@ static int delete_exec(bContext *C, wmOperator *op)
 						bezt++;
 					}
 					if(a==0) {
+						if(cu->actnu == nuindex)
+							cu->actnu= -1;
+
 						BLI_remlink(nubase, nu);
 						keyIndex_delNurb(editnurb, nu);
 						freeNurb(nu); nu= NULL;
@@ -5666,6 +5682,9 @@ static int delete_exec(bContext *C, wmOperator *op)
 						bp++;
 					}
 					if(a==0) {
+						if(cu->actnu == nuindex)
+							cu->actnu= -1;
+
 						BLI_remlink(nubase, nu);
 						keyIndex_delNurb(editnurb, nu);
 						freeNurb(nu); nu= NULL;
@@ -5681,6 +5700,7 @@ static int delete_exec(bContext *C, wmOperator *op)
 			}
 			*/
 			nu= next;
+			nuindex++;
 		}
 		/* 2nd loop, delete small pieces: just for curves */
 		nu= nubase->first;
@@ -5754,6 +5774,7 @@ static int delete_exec(bContext *C, wmOperator *op)
 		bezt1= bezt2= NULL;
 		bp1= bp2= NULL;
 		nu1= NULL;
+		nuindex= 0;
 		for(nu= nubase->first; nu; nu= nu->next) {
 			next= nu->next;
 			if(nu->type == CU_BEZIER) {
@@ -5810,10 +5831,14 @@ static int delete_exec(bContext *C, wmOperator *op)
 				}
 			}
 			if(nu1) break;
+			nuindex++;
 		}
 		if(nu1) {
 			if(bezt1) {
 				if(nu1->pntsu==2) {	/* remove completely */
+					if(cu->actnu == nuindex)
+						cu->actnu= -1;
+
 					BLI_remlink(nubase, nu);
 					freeNurb(nu); nu = NULL;
 				}
@@ -5857,6 +5882,9 @@ static int delete_exec(bContext *C, wmOperator *op)
 			}
 			else if(bp1) {
 				if(nu1->pntsu==2) {	/* remove completely */
+					if(cu->actnu == nuindex)
+						cu->actnu= -1;
+
 					BLI_remlink(nubase, nu);
 					freeNurb(nu); nu= NULL;
 				}
@@ -5891,6 +5919,7 @@ static int delete_exec(bContext *C, wmOperator *op)
 		}
 	}
 	else if(type==2) {
+		cu->actnu= -1;
 		keyIndex_delNurbList(editnurb, nubase);
 		freeNurblist(nubase);
 	}