Looks like duplicate of #84981 in terms that unlikely that default will be changed soon and picking other will solve this case.

@IllusionMH well, other diff chunk issues have been solved quite quickly in the past, see #119051 or #121436.

(Actually, #121436 seems closely related, so it might rather be a duplicate of that, but considering that that one is closed... It seems that issue's solution does not generalize to the case of having diff chunks following.)

/assign @alexdima (a person who resolved 2 previous)

OK, wasn't aware of that changes.

This is unfortunate, it has to do with how we compute diffs when trimming whitespace is not ignored: we actually compute the diff with trimming whitespace ignored and then introduce the char-level diffs for trimming whitespace. In this case, this backfires as there was a better } that could have been matched.

Fixed. Try the monaco playground link in the first issue with the latest dev!

@hediet I have two comments:

This screenshot seems to use ignoreTrimWhitespace: true. That is not what my issue was about, but I wonder if it was better if the original line 6 was deleted rather than original line 7, because the original line 7 is an exact match with the new line 5.

2. My original issue was about ignoreTrimWhitespace: false, in which case I get this:

This looks pretty much like the snapshot I posted in the original comment.

What has changed is that any additional CD/CE stuff does not impact the first chunk any longer - however, both cases (CD/CE and CD/CD) yield the non-minimal diff for the first chunk. So while the diff algorithm is more consistent now, its diffs tend to be longer than before. That is contrary of making them "minimal" ;)

I am checking out 1.82.0, and I would expect this fix to be in there. But it seems it is not:

Line 5 should not be part of the diff IMHO.

Can you check in your settings if you use the legacy diff algorithm?

Can you check in your settings if you use the legacy diff algorithm?

Do you mean diffEditor.diffAlgorithm? I have tried both options (legacy and advanced), and I don't see a difference between the two. Sometimes, diffEditor.ignoreTrimWhitespace does not seem to have an effect, either:

I will investigate this separately - maybe my profile is broken somehow (or maybe not, see below).

In a new Profile (using the advanced algorithm), I do see a difference depending on diffEditor.ignoreTrimWhitespace:

After settings the diff algorithm to legacy, the result is similar, although now the highlights are gone and diffEditor.ignoreTrimWhitespace has stopped working again:

This is the error I see in the console:

After setting the algorithm back to advanced and reloading, the error messages don't appear any more, but diffEditor.ignoreTrimWhitespace is still/again without effect.

TLDR: advanced algorithm, with whitespaces: new line 5 should not be part of the diff chunk because it is identical to old line 7.

Based on the Playground, I think this has been fixed in 0.42.0-dev-20230805 and is broken in 0.42.0-dev-20230804. Could it be that VS Code 1.82.0 ships with an older Monaco editor version?

1.82.0 ships with an older Monaco editor version?

That cannot be.

This is the error I see in the console:

I think this error is unrelated.

For the record, the whitespace-button-being-ineffective issue seems to be a duplicate of #174338. Changing the file type to plain text works around that problem.

Thanks! This looks perfect!

Comparing whitespace:

And also not comparing whitespace: