Warning for nonsense variables in config

[stephkyou]

Prints a warning if any nonsense variables are found in global or local config files whenever any CLI command is run. Also restricts users from adding any nonsense variables with dolt config --add or dolt config --set.

Resolves: #7165

[fulghum]

Looks good! Just a couple minor suggestions.

[fulghum]

Since anytime a new config value constant is added it'll need to be added to this map (i.e. high coupling), it's a good hint that these two pieces of code might benefit from being very close together. Try moving this map into the same file as where the config constants are defined.

There's another common Go trick for maps where you don't care about the values... you'll often see them written as:

var Foo = map[string]struct{}{
    "bar": {},
}

The advantage to that form is that it's unambiguous to future code readers (once you know this pattern at least) that the value of the map is ignored. If you use bool or string, then future code readers may think that the value has some meaning. It is also slightly more efficient for the runtime to store these, because there's an optimization where Go knows empty structs don't need to be allocated anywhere, as opposed to a bool or a string, which does require allocation, even if they are empty/false. It's a small efficiency gain, but worth knowing about, especially since you'll see this pattern fairly often.

[fulghum]

(minor) Might be worth running strings.ToLower on name here and for the local config section below. It does look like the current code always lowercases the names, but older versions may not have, plus people could always manually edit the config file.

[github-actions]

@coffeegoddd DOLT

test_name	detail	row_cnt	sorted	mysql_time	sql_mult	cli_mult
batching	LOAD DATA	10000	1	0.05	0.8
batching	batch sql	10000	1	0.07	1.43
batching	by line sql	10000	1	0.08	1.25
blob	1 blob	200000	1	0.89	3.18	3.65
blob	2 blobs	200000	1	0.87	4.17	4.78
blob	no blob	200000	1	0.88	1.32	1.41
col type	datetime	200000	1	0.79	1.82	2
col type	varchar	200000	1	0.65	2	2.08
config width	2 cols	200000	1	0.75	1.33	1.35
config width	32 cols	200000	1	1.87	1.39	2.49
config width	8 cols	200000	1	0.96	1.83	1.63
pk type	float	200000	1	0.89	1.21	1.2
pk type	int	200000	1	0.75	1.31	1.37
pk type	varchar	200000	1	1.53	0.99	0.96
row count	1.6mm	1600000	1	5.5	1.54	1.58
row count	400k	400000	1	1.38	1.5	1.49
row count	800k	800000	1	2.76	1.5	1.54
secondary index	four index	200000	1	3.5	1.1	0.95
secondary index	no secondary	200000	1	0.86	1.35	1.43
secondary index	one index	200000	1	1.11	1.54	1.5
secondary index	two index	200000	1	1.95	1.24	1.13
sorting	shuffled 1mm	1000000	0	5.17	1.77	1.8
sorting	sorted 1mm	1000000	1	5.31	1.8	1.74

[github-actions]

@coffeegoddd DOLT

name	detail	mean_mult
dolt_blame_basic	system table	1.08
dolt_blame_commit_filter	system table	2.79
dolt_commit_ancestors_commit_filter	system table	0.87
dolt_commits_commit_filter	system table	0.88
dolt_diff_log_join_from_commit	system table	1.73
dolt_diff_log_join_to_commit	system table	1.71
dolt_diff_table_from_commit_filter	system table	1.1
dolt_diff_table_to_commit_filter	system table	1.08
dolt_diffs_commit_filter	system table	1
dolt_history_commit_filter	system table	1.19
dolt_log_commit_filter	system table	0.88

[github-actions]

@coffeegoddd DOLT

name	add_cnt	delete_cnt	update_cnt	latency
adds_only	60000	0	0	0.72
adds_updates_deletes	60000	60000	60000	3.75
deletes_only	0	60000	0	1.84
updates_only	0	0	60000	2.37