build: introduce pre-commit framework

This replaces the custom clang-format script with the pre-commit framework,
making it easier to add checks in the future and simplifying GitHub
integration.

The GH workflow is adapted to run checks now as well.

To use it locally, all you need to do is install pre-commit locally, typically
via:
```
pip3 install --user pre-commit
```

You can then run `pre-commit run --all` to run it locally. Note that this does _not_ install
a Git hook. If you want that as well, run `pre-commit install`.

For more details on pre-commit and other installation options, see
https://pre-commit.com and https://pre-commit.com/#install

This commit also applies the fixes from `pre-commit run --all`, but
modifies the changes to solution templates to contain a comment, so that
we don't end up with `namespace foo {}` lines.

[no important files changed]

Author: ahans

.github/workflows/pre-commit.yml

@@ -0,0 +1,26 @@
+name: Pre-commit checks
+
+on:
+  # Run workflow for PRs.
+  pull_request:
+
+  # Whenever we have a new commit on main, run the workflow for that.
+  push:
+    branches: [main]
+
+jobs:
+  pre-commit:
+    name: Pre-commit checks
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          ref: ${{github.event.pull_request.head.sha}}
+          repository: ${{github.event.pull_request.head.repo.full_name}}
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+      - name: Run pre-commit checks on PR
+        uses: pre-commit/[email protected]

.github/workflows/verify-code-formatting.yml

@@ -0,0 +1,9 @@
+exclude: 'test/(catch.hpp|tests-main.cpp)'
+
+repos:
+-   repo: https://github.com/pre-commit/mirrors-clang-format
+    rev: v18.1.2
+    hooks:
+    -   id: clang-format
+        exclude_types: [json]
+

.pre-commit-config.yaml

@@ -1,3 +1,8 @@
 // ERROR: FILE CORRUPTED. Please supply valid C++ Code.
 
-hp1,üapöhp2ö%Äcountöiöma1,öhp2ö%Älawöhp3öö/önextöstepö%Ädacöiöml1ö%Älawö7ö%Ädacöiömb1ö%Ärandomöö%Äscrö9sö%Äsirö9sö%Äxctöhr1ö%Äaddöiömx1ö%Ädacöiömx1ö%Äswapö%Äaddöiömy1ö%Ädacöiömy1ö%Ärandomö%Äscrö9sö%Äsirö9sö%Äxctöhr2ö%Ädacöiömdyö%Ädioöiömdxö%Äsetupö.hpt,3ö%Älacöranö%Ädacöiömth
+hp1, üapöhp2ö % Äcountöiöma1,
+    öhp2ö % Älawöhp3öö / önextöstepö % Ädacöiöml1ö % Älawö7ö % Ädacöiömb1ö %
+        Ärandomöö % Äscrö9sö % Äsirö9sö % Äxctöhr1ö % Äaddöiömx1ö %
+        Ädacöiömx1ö % Äswapö % Äaddöiömy1ö % Ädacöiömy1ö % Ärandomö % Äscrö9sö %
+        Äsirö9sö % Äxctöhr2ö % Ädacöiömdyö % Ädioöiömdxö % Äsetupö.hpt,
+    3ö % Älacöranö % Ädacöiömth

bin/check-formatting.sh

@@ -31,7 +31,7 @@ void increment_vote_count(ElectionResult& result, int votes) {
 ElectionResult& determine_result(std::vector<ElectionResult>& count) {
     int winner_idx = 0;
     for (int i{}; i < count.size(); ++i) {
-        if(count.at(i).votes > count.at(winner_idx).votes) {
+        if (count.at(i).votes > count.at(winner_idx).votes) {
             winner_idx = i;
         }
     }

exercises/concept/doctor-data/doctor_data.h

@@ -16,19 +16,16 @@ struct ElectionResult {
 // vote_count takes a reference to an `ElectionResult` as an argument and will
 // return the number of votes in the `ElectionResult.
 
-
 // TODO: Task 2
 // increment_vote_count takes a reference to an `ElectionResult` as an argument
 // and a number of votes (int), and will increment the `ElectionResult` by that
 // number of votes.
 
-
 // TODO: Task 3
 // determine_result receives the reference to a final_count and returns a
 // reference to the `ElectionResult` of the new president. It also changes the
 // name of the winner by prefixing it with "President". The final count is given
 // in the form of a `reference` to `std::vector<ElectionResult>`, a vector with
 // `ElectionResults` of all the participating candidates.
 
-
 }  // namespace election

exercises/concept/election-day/.meta/exemplar.cpp

@@ -63,7 +63,6 @@ TEST_CASE("Presidency, two candidates", "[task_3]") {
     REQUIRE(result.name == expected);
 }
 
-
 TEST_CASE("Presidency, several candidates", "[task_3]") {
     ElectionResult option1{"David", 11};
     ElectionResult option2{"Shaw", 12};