Tested the issue on Android and able to reproduce this issue.

Steps Followed:
1. Launch chrome
2. In omni box search for lionel messi 
3. tap on up arrow beside lionel messi
4. Observed that no space is apended after the word lionel messi.

Chrome versions tested:
60.0.3072.0, 67.0.3396.87(Stable), 69.0.3487.0(Canary)

OS:
Android 8.1.0

Android Devices:
Nexus 6p 

This seems to be a Non-Regression issue as same behavior is seen since M-60. Leaving the issue as Untriaged for further input's on this issue.

Please navigate to below link for log's --
go/chrome-androidlogs/862404
 
Thanks!

I agree that this would be useful. Same for iOS.

tedchoc, justincochen: I assume this would be a pretty quick fix.

Reproduces on iOS as well.

Would this need to be limited to certain character sets?  Are there languages where spaces are not needed/used for longer query formation?

I suspect there are also people that use the arrows to form URLs, but I would suspect that would be by far the minority.

is it possible to only insert a space for query suggestions and not for URL suggestions? 

Yeah, that should be possible.  When typing the initial word, it can be hard to determine if it is a query or a URL fragment.

If you're typing "face" and the refinement arrow is "facebook", would you want a space after it?  The hope is that we'd also provide a "facebook.com" suggestion that would prevent the need for this, but I don't think that is a 100% reliable.

I think it's fair to try for query suggestions and even if single word URL-ish happens, I don't think it is the most common thing.

I just noticed the YouTube for Android app also has this issue (not inserting a space after you the tap arrow beside suggestions), can someone reach out to the YouTube team to get them to fix it? YouTube for iOS doesn't have the issue

re #9:
I filed b/111760967 in Google's internal bug tracker for the YouTube issue.  Thanks for reporting!

stkhapugin@ PTAL at the iOS side of the issue

I don't think there's consensus about this yet? 

Can we learn from how the google app and google.com handle these possible issues of deciding whether users are entering a search or a URL? Maybe we can borrow from their approach. 

I think we should insert a space if the suggestion being selected is a query string and not insert a space when it's a URL. 

jdonnelly@: Does that sound reasonable to you?

I looked at the GSA code and it appears to unconditionally append whitespace regardless of language.

http://shortn/_bJgxxzpHbu

I (with the help of changwan@ and bauerb@) tested Chinese, Korean, Hebrew on google.com and it unconditionally appends a " " as well.

I think this seems safe to just unconditionally add a space for queries.

iGSA appends unconditionally only if it's a query. When it's a URL, they don't append a space. That is basically my proposal in #15. 

The URL vs query wasn't my concern.

My concern was around inputting queries in languages that do not use spaces unconditionally for word breaks and queries that "could" be URLs (comment #6, #8), but it appears that the existing properties don't make any distinction around that, so I don't think Chrome would need to either.

I understand. I was just saying that making the distinction would be good. i.e. wanting to add a '/path' after i picked the URL without having to click backspace. I thought this is what you meant in #8

In #8, I was aiming to highlight the case where you're typing something that could either be a query or a URL.

If you typed, "face", the suggestion option could be "facebook".  If you wanted to navigate to "facebook.com", you would not need to hit backspace and then type ".com".

In this case, the query has a strong correlation to a very popular URL, but we would only know it is a query.  I personally think this isn't a super prevalent case, but it was the one where query vs URL wasn't a prefect distinction IMO.

Is there any data for people tapping the spacebar, but also, data for people backspacing? That could be helpful if we wanted to make this perfect 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c7565782959525eb3d5f2ea6a032bd97e4da19a7

commit c7565782959525eb3d5f2ea6a032bd97e4da19a7
Author: Ted Choc <tedchoc@google.com>
Date: Fri Aug 03 23:26:08 2018

Add a space after refine omnibox query suggestions.

BUG= 862404 

Change-Id: I39a49e01d58fb4c83d8a78002e442f6245bf0ea4
Reviewed-on: https://chromium-review.googlesource.com/1162674
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580700}
[modify] https://crrev.com/c7565782959525eb3d5f2ea6a032bd97e4da19a7/chrome/android/java/src/org/chromium/chrome/browser/omnibox/LocationBarLayout.java

is this fixed in iOS version 70? Just tried it on version 69 and still no space for query suggestions

As near as I can tell, no one has submitted any code on iOS to fix it.

The fix for Android will be in Chrome 71.

It's already fixed in Android version 70 canary :) 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cbf437674b80d68a419df3ddd50588cb91422cdd

commit cbf437674b80d68a419df3ddd50588cb91422cdd
Author: stkhapugin@chromium.org <stkhapugin@chromium.org>
Date: Tue Sep 11 14:19:34 2018

[iOS] Add a space to refine query suggestions.

Bug:  862404 
Change-Id: I3d775805657d7303cfbf6a04f581d855deb5717b
Reviewed-on: https://chromium-review.googlesource.com/1219507
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590296}
[modify] https://crrev.com/cbf437674b80d68a419df3ddd50588cb91422cdd/ios/chrome/browser/ui/omnibox/popup/omnibox_popup_view_ios.mm

Should be fixed on iOS now!