ensure immutable databses when starting in configuration directory mode with

[camallen]

fixes #1224

This PR ensures all databases found in a configuration directory that match the files in inspect-data.json will be set to immutable as outlined in https://docs.datasette.io/en/latest/settings.html#configuration-directory-mode

specifically on building the datasette instance it checks:

• if immutables is an empty tuple - as passed by the cli code
• if immutables is the default function value None - when it's not explicitly set

And correctly builds the immutable database list from the inspect-data[file] keys.

Note for this to work the inspect-data.json file must contain file paths which are relative to the configuration directory otherwise the file paths won't match and the dbs won't be set to immutable.

I couldn't find an easy way to test this due to the way make_app_client works, happy to take directions on adding a test for this.

I've updated the relevant docs as well, i.e. use the inspect cli cmd from the config directory path to create the relevant file

cd $config_dir
datasette inspect *.db --inspect-file=inspect-data.json

https://docs.datasette.io/en/latest/performance.html#using-datasette-inspect

[codecov]

Codecov Report

Merging #1229 (a095248) into main (8e18c79) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1229   +/-   ##
=======================================
  Coverage   91.51%   91.51%           
=======================================
  Files          34       34           
  Lines        4255     4255           
=======================================
  Hits         3894     3894           
  Misses        361      361           

Impacted Files	Coverage Δ
datasette/app.py	95.85% <100.00%> (ø)

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[camallen]

I believe this pr and #1031 are related and fix the same issue.

[simonw]

Thanks for figuring this out!