MGS1040: magus.yaml has a key this magus does not know

A config file carries a key the running magus does not recognize, and every command stops before it loads the workspace:

[MGS1040] magus.yaml:1: unknown key "concurrencyy"; did you mean "concurrency"?
  see: https://eli.gladman.cc/magus/reference/codes/magusfile/MGS1040/

Each unknown key gets its own line, at every level of the file, not only the top.

Why

Until v0.5.0 an unknown key was a warning (config: unknown or unexpected keys in config file) and the load carried on without it. The value you wrote was dropped, and a workspace that looked configured ran on the defaults. A value magus will not honor must never look like one it applied, so the load now fails instead. A file that loaded under v0.4.x with that warning fails under v0.5.0 with this code.

What to do

Read the tail of the message. It takes one of two forms, with opposite fixes:

• did you mean "..."? The key is a near miss of one magus knows. Rename it:

  # before
  concurrencyy: 4
  # after
  concurrency: 4
  

• this magus does not know that key Nothing known is close. Either the key belongs to a newer magus than the one running, so upgrade the binary (the message names the command, and the workspace's required_version if it has one), or the key is not a magus setting at all and the fix is to delete it.

magus doctor reports the same keys under its config-file check without running anything else. docs/reference/config lists every key magus reads.

See also

• MGS1021: the workspace's required_version floor is newer than this magus.
• MGS1038: the same stop for a removed magus.project option in a magusfile.