Table widget crash when scrolling rapidly

[wenhsinhsieh]

Describe the bug:

The table widget goes panic when scrolling up and down rapidly

To Reproduce:

Steps to reproduce the behaviour:

1. Run fyne_demo
2. switch to Collections-> Table
3. maximize window
4. mouse hold on vertical scroll bar can scroll up and down rapidly
5. eventually the program goes panic

Note: It seems doesn't happen (or maybe hard to reproduce) if the window is not maximize. It also doesn't happen if scrolling slowly.

Screenshots:

Device (please complete the following information):

• OS: Windows
• Version: 10
• Go version: 1.14.6
• Fyne version: 2.0

[wenhsinhsieh]

Additional info: Linux also happens too.

Device (please complete the following information):

• OS: Ubuntu
• Version: 18.04
• Go version: 1.14.7
• Fyne version: 2.0

Callstack:

panic: runtime error: index out of range [31] with length 31

goroutine 15 [running, locked to thread]:
fyne.io/fyne/v2/widget.(*tableRenderer).moveIndicators(0xc0003096c0)
	/home/user/go/src/fyne.io/fyne/v2/widget/table.go:350 +0xc65
fyne.io/fyne/v2/widget.(*tableRenderer).Layout(0xc0003096c0, 0x4443400044b7b333)
	/home/user/go/src/fyne.io/fyne/v2/widget/table.go:240 +0x2f
fyne.io/fyne/v2/internal/driver/glfw.updateLayout(0xb5eb20, 0xc000a3a780)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/canvas.go:638 +0x122
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).ensureMinSize.func1(0xc000c18f80)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/canvas.go:349 +0x18d
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).walkTree.func2(0xb5d860, 0xc000a29b60, 0xb5ea60, 0xc000028ab0)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/canvas.go:531 +0xd8
fyne.io/fyne/v2/internal/driver.walkObjectTree(0xb5d860, 0xc000a29b60, 0x4443400043bfb300, 0xb5ea60, 0xc000028ab0, 0x4443400043bfb333, 0x0, 0x4f0000004f000000, 0xc001317cd8, 0xc001317cb0, ...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:197 +0x338
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0xb5ea60, 0xc000028ab0, 0x42f0000043bdb300, 0xb5eb20, 0xc000a3a780, 0x42f0000043bdb333, 0x0, 0x4f0000004f000000, 0xc001317cd8, 0xc001317cb0, ...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:190 +0x41d
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0xb5eb20, 0xc000a3a780, 0x42f0000043bdb300, 0xb5d5c0, 0xc0000b0780, 0x42f0000043bdb333, 0x0, 0x4f0000004f000000, 0xc001317cd8, 0xc001317cb0, ...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:190 +0x41d
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0xb5d5c0, 0xc0000b0780, 0x4204000043bdb300, 0xb5d5c0, 0xc000178100, 0x4204000043bdb333, 0x0, 0x4f0000004f000000, 0xc001317cd8, 0xc001317cb0, ...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:190 +0x41d
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0xb5d5c0, 0xc000178100, 0x4204000040800000, 0xb5daa0, 0xc000218ee0, 0x4204000040800000, 0x0, 0x4f0000004f000000, 0xc001317cd8, 0xc001317cb0, ...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:190 +0x41d
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0xb5daa0, 0xc000218ee0, 0x10daab00, 0x0, 0x0, 0x0, 0x0, 0x4f0000004f000000, 0xc001317cd8, 0xc001317cb0, ...)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:190 +0x41d
fyne.io/fyne/v2/internal/driver.WalkVisibleObjectTree(0xb5daa0, 0xc000218ee0, 0xc001317cd8, 0xc001317cb0, 0xc001317cc8)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/util.go:134 +0x94
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).walkTree(0xc000034200, 0xc000478160, 0x0, 0xc001317db0)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/canvas.go:537 +0x15c
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).walkTrees(0xc000034200, 0x0, 0xc001317db0)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/canvas.go:544 +0x4f
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).ensureMinSize(0xc000034200, 0xc001317e20)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/canvas.go:354 +0x98
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).repaintWindow.func1()
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/loop.go:156 +0x40
fyne.io/fyne/v2/internal/driver/glfw.(*window).RunWithContext(0xc000196540, 0xc001317e58)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/window.go:1181 +0x38
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).repaintWindow(0xc0000bc730, 0xc000196540)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/loop.go:155 +0x60
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).startDrawThread.func1(0xc0000bc730, 0xc00002c840, 0xc0000bc820)
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/loop.go:211 +0x22c
created by fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).startDrawThread
	/home/user/go/src/fyne.io/fyne/v2/internal/driver/glfw/loop.go:182 +0xbd

[andydotxyz]

This should now be fixed on the develop branch. If you are able to test that would be excellent.

[andydotxyz]

This was resolved in v2.0.1