📝 define MSRV

[kevinmatthes]

As discussed in #248, it might be worth discussing whether this project should specify a certain Rust version as the Minimal Supported Rust Version (MSRV). This PR adds the basic setup for the current stable Rust version (v1.72.0):

• configuration for Clippy
• configuration for Cargo
• a badge for the README for documentation purposes

I would like to discuss the following questions:

• Should this project have an explicit MSRV specified somewhere; @ttytm?
• Which Rust version should be used as MSRV?
• Should there be a badge in the README stating the configured MSRV? If so, which colour shall it have?
• How shall the MSRV be updated automatically? (This works with Renovate, I just need to know the period of time to pass before the next MSRV is suggested.)

[github-actions]

Filename                              Stmts    Miss  Cover    Missing
----------------------------------  -------  ------  -------  ------------------------------------------------------------
src/modules/api.rs                       24      13  45.83%   26-29, 38, 49-88
src/modules/args.rs                       4       4  0.00%    91-95
src/modules/config.rs                    32      26  18.75%   52-97
src/modules/forecast.rs                  20       6  70.00%   7-8, 24-25, 27-28
src/modules/localization.rs             108      44  59.26%   162-203, 230-265
src/modules/location.rs                  55      28  49.09%   25-29, 59-63, 75, 89, 95-104, 109, 118-126, 131-132, 142-143
src/modules/params.rs                    67      67  0.00%    24-137
src/modules/units.rs                     13       0  100.00%
src/modules/weather.rs                   25      25  0.00%    83-148
src/main.rs                              17      17  0.00%    26-49
src/modules/display/border.rs            47      47  0.00%    17-106
src/modules/display/current.rs          124     124  0.00%    37-243
src/modules/display/day.rs               92      92  0.00%    29-164
src/modules/display/graph.rs            175     170  2.86%    65-368
src/modules/display/gui_config.rs        15      12  20.00%   46-61
src/modules/display/historical.rs        98      98  0.00%    35-201
src/modules/display/hourly.rs           211     211  0.00%    40-396
src/modules/display/product.rs           21      21  0.00%    24-64
src/modules/display/utils.rs             46      46  0.00%    6-85
src/modules/display/weathercode.rs       34      34  0.00%    11-46
src/modules/display/week.rs              68      68  0.00%    30-137
src/modules/display/wind.rs              22      22  0.00%    17-42
TOTAL                                  1318    1175  10.85%

[github-actions]

Test Results

  3 files    3 suites   3s ⏱️
  9 tests   9 ✔️ 0 💤 0 ❌
27 runs  27 ✔️ 0 💤 0 ❌

Results for commit 03b6637.

♻️ This comment has been updated with latest results.

[kevinmatthes]

I just tested whether there is a default colour for the MSRV badge; there is none. So, we need to decide for / agree on a colour. The submitted suggestion uses "brightgreen" but I also saw "orange" and "green" (more yellow than green, in my opinion). If the colours are the same as for the other badges, "blue" and "violet" should work, as well.

[ttytm]

I'm currently on vacation. I'll look into it when a free moment opens up 👍

[github-actions]

The MSRV will not change.

[kevinmatthes]

At least does the MSRV checking workflow work -- despite the contained stylistic issues!

[kevinmatthes]

I am sorry, the workflow for the MSRV check does not work as expected. I will remove it for now and add it in a separate PR.

[ttytm]

The check can fit as part of the lint workflow as msrv job. It should be possible to give permission on per job basis.

[ttytm]

Thanks for the work @kevinmatthes !

[ttytm]

To further simplify it, a failing CI step would suffice. Something like this might work.

cargo msrv list 2> versions.txt
new="$(egrep [[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+ versions.txt | tail -n 1 | cut -d \  -f 2)"
current=$(cat .clippy.toml | cut -d \" -f 2)
if [ "$new" != "$current" ]; then
	echo "MSRV missmatch: $new != $current"
	exit 1
fi

Seeing a CI step failing and checking the output if necessary is more convenient than adding comments to the PR. It will be a clear enough indicator and would keep the PR cleaner.