Tabs are not sometimes not indenting on 2025-06

[jsattard]

Long time eclipse user, upgraded to 2025-06 and found that our codebase which has a mix of spaces + tabs is now sometimes not indenting tabs.

Tabs are set to 4 width. You can see from the screenshot with whitespace characters enabled there is a tab here, but it doesn't indent at all, meanwhile others do. If I delete them all and re-create them, it works fine.

I tried to

• Reinstall eclipse, deleting all my users/.p2 and .eclipse directories as well as the .metadata directory in my workspace

Any help would be appreciated!

[jsattard]

I should add, I have re-installed 2025-03 and it works fine.

[iloveeclipse]

Honestly, I can't spot the problem. Could you add screenshot from same example whereit is supposed to be "good"?

[jsattard]

With whitespace enabled, it's hard to see, but behind those letters in teal (blockingQueue, running, renderThread etc.) there is a tab that looks like ">>". When tabs are encountered, it is supposed to indent them by 4 spaces. It does that just a few lines below, the line with "watchdog" has a tab that indents, and a tab that doesn't. Here it is in 2025-03 where all the tabs are indented by 4:

[merks]

I see what you mean that there is a barely visible tab underneath letter that should be indented.

All attempts to reproduce such a problem in a *.java file by adding spaces before a tab results in the jump to the right when there is no more room left for the 4 space tab:

for

 	// test
  	// test
   	// test
    	// test

The OS might make a difference too. I'm on Windows.

[jsattard]

I am also on windows and yeah, I can confirm that if I delete the tabs and re-add them, it works fine. It just seems to be loading any of the old files. I've uploaded the full file (wouldn't accept .java extension so renamed to .txt), maybe this will give you a reproduction if you try to load it directly?

GPUCanvas.txt

Oh, it also looks fine if I just mass replace all sets of 4 spaces with tabs. Other files that are all tabs or all spaces work fine. So it seems to be the mixing of tabs and spaces that's a problem.

[merks]

It looks okay for me (with the latest 4.37-I-build):

[jsattard]

I was afraid you'd say that - I don't suppose there were any code changes in that area from 2025-03 to 2025-06 that might be a culprit? Been using Eclipse for over 20 years (with the same files you're seeing here) and never experienced this, but I expect it would be difficult to resolve without a reproduction on your end.

[merks]

I don't really know where such code would live or how that is implemented. Maybe in StyledText but there is not much activity there:

I have no clue. 😢

[CaveRenderPro]

I have the same problem with 2025-06 2025-06 (4.36.0). 4 spaces and a tab don't set the cursor to position 8.

[Ema-08]

I have the same issue on 2026 06 release, and changing the text font (Basic -> Text Font) to the system default seems to be a valid workaround.

[vogella]

Fix proposed in eclipse-platform/eclipse.platform.swt#3493. If one of the reporter could test, that would be awesome.