TextMesh Pro Huge GC Alloc by assigning text

First of all, I would like to thank you for this awesome tool, and the support you are providing. Unfortunately, I have stumbled upon an issue, I can't resolve using the already given answers.

Versions:
Unity 2019.4.16f1
TMP 2.1.3

If I assign a text at runtime, that is about 100 characters long (and with rich tags (font, color, size) it would be about double that), I get huge spikes in the profiler after I press the spacebar.

Code (CSharp):

1.     [SerializeField] string textToTest;
2.  
3.     TMP_Text text;
4.     void Awake() => text = GetComponent<TMP_Text>();
5.     void Update()
6.     {
7.         if (Input.GetKeyDown(KeyCode.Space))
8.             text.text = textToTest;
9.     }
10.  

Here I have pressed the spacebar.

Here I have manually cleared in the TMP component the inputted text

And here I have pressed the spacebar again



What am I trying to achieve? I want to assign different prewritten text (with no concatenation and so on) to the same textbox at runtime once I press a specific button.
I assumed that simply using .text would do it, but is there perhaps some other way of achieving 0 GC text assigning in my situation?

 

I profiled on a standalone build with the same result.
I also noticed, that if I reassign the same text into the same field, I get about 10% of that Garbage.
So it has something to do with some sort of resizing.

 

Update:
I am also getting garbage without using rich tags, just a bit less. Less perhaps due to the fact, that less text is actually being assigned.

 

When the text object is awaken and text is first assigned to it, some allocations will occur to allocate the relevant buffers for text processing and geometry.

Subsequent changes to the text provide the text doesn't change length by more than a factor of 2 will not result in further allocations.

Are you seeing these allocations on first invocation or on subsequent assignment?

 

I have 0b allocation later on. This happens only once. In fact, I have almost the same result with the standard Unity text solution. But still. I won't be having just one text box to fill. And having 500.000b worth of garbage every time the box gets filled once seems to be just unacceptable. Was it always like that? I even tried the latest 2020 version with the same result.
Is there a way to allocate the relevant buffers on level start rather than during gameplay?

 

These allocations will occur when the text object is first created and text assigned to it which can occur as a scene is loaded that contains text objects or if you have a logic that instantiates those object when loading your levels.

Once the object has been created, no further allocations will occur unless the text grows in size as per my previous post.

These allocations will remain for the life of the text object.

The size of the allocations is relative to the amount of text contained in the text object.

Make sure you are using the latest release of the TMP package which includes some reduction in memory overhead as some of the data structures used in the parsing and layout of the text is shared between objects.