Sketcher: Failed to validate broken face and/or Crash

[ceremcem]

Description

This problem occurs when we use external geometry via sub-shape binder and then solve the constraints.

Reproduction

1. Get a solid (A)
2. Draw a sketch (Sketch) using constraints to the external geometry (ExtConstraints) via sub-shape binder (Binder) of A
3. Pad it to create a solid (B)
4. Create a constraint between A and B
5. Disable "Auto Recompute" (do not solve constraints automatically)
6. Move A
7. Click "Refresh" button (at the top)
8. See everything is normal and B is moved accordingly (Because when we move A, Binder is moved accordingly, thus the ExtConstraints are moved, thus Sketch is moved/re-drawn to/at the correct position.
9. Press "Solve constraints"

Then one of the followings may happen:

You'll end up with broken face:

How to fix: Open the sketch in edit mode, then close. You don't need to fix anything here.

or with a crash:

(previous outputs seem irrelevant)
Link to Edge10 already exists in this sketch.
Failed to add external geometry: Not able to add external shape element
Link to Edge10 already exists in this sketch.
Failed to add external geometry: Not able to add external shape element
Selected external reference plane must be normal to sketch plane
Failed to add external geometry: Not able to add external shape element
Selected external reference plane must be normal to sketch plane
Failed to add external geometry: Not able to add external shape element
Link to Edge14 already exists in this sketch.
Failed to add external geometry: Not able to add external shape element
Link to Edge20 already exists in this sketch.
Failed to add external geometry: Not able to add external shape element
Updating geometry: Error build geometry(5): 
Invalid solution from DogLeg solver.
Drag curve: Not able to move point with the id and type: (3, 0)
Drag curve: Not able to move point with the id and type: (3, 0)
<asm3.sys> 0.000211 - solver.py(119): List of failed constraint:
"Constraint005(hat-offset)"<PlaneAlignment>, handle: 2
Updating geometry: Error build geometry(4): 
Invalid solution from DogLeg solver.
Updating geometry: Error build geometry(5): 
Invalid solution from DogLeg solver.
1.02e-07 Tree.cpp(2595): [ComboView] sub object not found Sketch009.;H_Axis.
Program received signal SIGSEGV, Segmentation fault.

On re-start, you'll see a recovery screen. Click "recover", wait for a while and see the documents are loaded in the tree. You'll end up with broken links. Close the project, say "yes" to "should we save the file?" prompts, then re-open the project.

or incorrect Placement (mostly this one happens)

You may end up with incorrect placement, because Binder isn't moved to the correct position (screencast).

Fix: Double click the Binder in the tree, it will be updated to the correct position, thus the sketch will be updated. Click "Reload" button at the top, and B is placed to the correct position.

Attachments

case-v3-20180913T1210.zip

[realthunder]

Anything after the SIGSEGV? Those are the import ones.

[ceremcem]

Nope. Nothing more at the bottom.

[ceremcem]

I tried the same steps a few more times, even with the project snapshots which are taken before the crash (old versions of the project files) but there is no crash happened in those attempts.