Non-default table prefix not used with new src/build flow, results in "You appear to have already installed WordPress" message

[allendav]

Observed with today's trunk. Steps to reproduce:

(NOTE: Assumes old WordPress tables with wp_ prefix are present in your local MySQL database, e.g. from another local installation.)

• cd /Library/WebServer/Documents (or wherever your web server root is)
• mkdir wordpress-svn
• cd wordpress-svn
• svn co ​https://develop.svn.wordpress.org/trunk/ .
• npm install && grunt build
• In your web browser, navigate to ​http://localhost/wordpress-svn/build

you’ll be taken to ​http://localhost/wordpress-svn/build/wp-admin/setup-config.php

• pick your language (e.g. English) and click continue
• On the welcome page ( step=0 ), click Let’s go!
• On the connection details page (step=1 ) enter the details including a table prefix other than wp_ (e.g. wp99_) and click Submit
• On the sparky page (step=2), click Run the Installation

You’ll be sent to ​http://localhost/wordpress-svn/build/wp-admin/install.php?language=en_US and see

Already Installed
You appear to have already installed WordPress. To reinstall please clear your old database tables first.

• Open build/wp-config.php and note that all your connection details are present EXCEPT FOR the table prefix
• Change the table prefix to whatever you set using your favorite editor

• Refresh ​http://localhost/wordpress-svn/build/wp-admin/install.php?language=en_US

NOW, you’ll be on the “famous five-minute” install page, where you can complete installation.

[allendav]

I think I chose the wrong Component when I opened this originally.

[SergeyBiryukov]

Also reported by @sergeykovalets.

[SergeyBiryukov]

The new src/build flow is unrelated, the issue is caused by [42343], which removed an extra space from the $table_prefix = 'wp_'; line in wp-config-sample.php, but wp-admin/setup-config.php​ still accounts for that extra space.

Adjusting lines 350 and 351 to remove the space before = fixes the issue.

[dontgo2sleep]

Replying to shashwatmittal:
Why the issue is reopened?

[SergeyBiryukov]

Tickets are closed when a patch is committed to WordPress core.

[shashwatmittal]

Replying to SergeyBiryukov:

Tickets are closed when a patch is committed to WordPress core.

Was not of aware of that. Thanks, will keep in mind the next time.

[SergeyBiryukov]

Replying to shashwatmittal:

Was not of aware of that. Thanks, will keep in mind the next time.

No worries, thanks for the patch :)

[SergeyBiryukov]

In 43650:

Upgrade/Install: Adjust table prefix string check in setup-config.php for the coding standards change in [42343].

Props shashwatmittal, allendav.
Fixes #44318.

[SergeyBiryukov]

Switching milestone due to the focus on the new editor (Gutenberg) for WordPress 5.0.