Cannot connect to database!
 Error 1045: Access denied for user 'root'@'localhost' (using password: NO)

Your password for database is empty and is required.

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 Database migrations failed!
 ... error here ...

Please open an issue, tell us you database version & configuration.

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Upgrades failing

You might see a message like this:

semaphore not found in $PATH. Upgrading will not work.

You should move the semaphore binary to a location inside $PATH and run semaphore from there.

Why?

Well it isn't really possible for programs to tell where the binary is launched from. The program does its best to locate the binary by looking inside $PATH and argv[0]. See this SO question.