Avoid dagerous move without tool height compensation after setting first fixture

The issue only happen when splitting jobs on tools (orderby == Tool), and when
USE_TLO was active and the preamble include G49.  The first move is then done
before tool height is set, and can cause damage if the existing tool height is set
to more than the gap between the spindle and the table or work piece, when the machine
take a sudden dive straight down.

Removed move between G49 and first G43, to ensure all moves are done after G43
correctly set tool height compensation.

Rewrote code to introduce new method fixtureSetup() to ensure all orderby alternatives
behave the same way.

Fixes #9866.

src/Mod/Path/Path/Post/Command.py

@@ -256,6 +256,33 @@ def resolveFileName(job, subpartname, sequencenumber):
     return fullPath
 
 
+def fixtureSetup(order, fixture, job):
+    """Convert a Fixure setting to _TempObject instance with a G0 move to a
+    safe height every time the fixture coordinate system change.  Skip
+    the move for first fixture, to avoid moving before tool and tool
+    height compensation is enabled.
+
+    """
+
+    fobj = _TempObject()
+    c1 = Path.Command(fixture)
+    fobj.Path = Path.Path([c1])
+    # Avoid any tool move after G49 in preamble and before tool change
+    # and G43 in case tool height compensation is in use, to avoid
+    # dangerous move without tool compesation.
+    if order != 0:
+        c2 = Path.Command(
+            "G0 Z"
+            + str(
+                job.Stock.Shape.BoundBox.ZMax
+                + job.SetupSheet.ClearanceHeightOffset.Value
+            )
+        )
+        fobj.Path.addCommands(c2)
+    fobj.InList.append(job)
+    return fobj
+
+
 def buildPostList(job):
     """Takes the job and determines the specific objects and order to
     postprocess  Returns a list of objects which can be passed to
@@ -273,20 +300,7 @@ def buildPostList(job):
         currTool = None
         for index, f in enumerate(wcslist):
             # create an object to serve as the fixture path
-            fobj = _TempObject()
-            c1 = Path.Command(f)
-            fobj.Path = Path.Path([c1])
-            if index != 0:
-                c2 = Path.Command(
-                    "G0 Z"
-                    + str(
-                        job.Stock.Shape.BoundBox.ZMax
-                        + job.SetupSheet.ClearanceHeightOffset.Value
-                    )
-                )
-                fobj.Path.addCommands(c2)
-            fobj.InList.append(job)
-            sublist = [fobj]
+            sublist = [fixtureSetup(index, f, job)]
 
             # Now generate the gcode
             for obj in job.Operations.Group:
@@ -310,20 +324,9 @@ def buildPostList(job):
 
         # Build the fixture list
         fixturelist = []
-        for f in wcslist:
+        for index, f in enumerate(wcslist):
             # create an object to serve as the fixture path
-            fobj = _TempObject()
-            c1 = Path.Command(f)
-            c2 = Path.Command(
-                "G0 Z"
-                + str(
-                    job.Stock.Shape.BoundBox.ZMax
-                    + job.SetupSheet.ClearanceHeightOffset.Value
-                )
-            )
-            fobj.Path = Path.Path([c1, c2])
-            fobj.InList.append(job)
-            fixturelist.append(fobj)
+            fixturelist.append(fixtureSetup(index, f, job))
 
         # Now generate the gcode
         curlist = []  # list of ops for tool, will repeat for each fixture
@@ -378,7 +381,6 @@ def buildPostList(job):
         # Order by operation means ops are done in each fixture in
         # sequence.
         currTool = None
-        firstFixture = True
 
         # Now generate the gcode
         for obj in job.Operations.Group:
@@ -390,22 +392,8 @@ def buildPostList(job):
             sublist = []
             Path.Log.debug("obj: {}".format(obj.Name))
 
-            for f in wcslist:
-                fobj = _TempObject()
-                c1 = Path.Command(f)
-                fobj.Path = Path.Path([c1])
-                if not firstFixture:
-                    c2 = Path.Command(
-                        "G0 Z"
-                        + str(
-                            job.Stock.Shape.BoundBox.ZMax
-                            + job.SetupSheet.ClearanceHeightOffset.Value
-                        )
-                    )
-                    fobj.Path.addCommands(c2)
-                fobj.InList.append(job)
-                sublist.append(fobj)
-                firstFixture = False
+            for index, f in enumerate(wcslist):
+                sublist.append(fixtureSetup(index, f, job))
                 tc = PathUtil.toolControllerForOp(obj)
                 if tc is not None:
                     if job.SplitOutput or (tc.ToolNumber != currTool):