feat: outputting in GitHub Actions error format

Author: DeveloperC286

src/linting_results/github_actions.rs

@@ -0,0 +1,49 @@
+use std::fmt::Write;
+
+use super::{CommitError, CommitsError, LintingResults};
+
+pub(crate) fn print_all(results: &LintingResults) -> String {
+    let mut output = String::new();
+
+    if let Some(commit_errors) = &results.commit_errors {
+        for commit in &commit_errors.order {
+            if let Some(errors) = commit_errors.errors.get(commit) {
+                let short_hash = &commit.hash[..7.min(commit.hash.len())];
+                let message = commit.message.lines().next().unwrap_or_default();
+
+                let _ = writeln!(output, "::group::{short_hash} - {message}");
+
+                for error in errors {
+                    match error {
+                        CommitError::MergeCommit => {
+                            let _ = writeln!(
+                                output,
+                                "::error title=Merge Commit::Commit {short_hash} is a merge commit."
+                            );
+                        }
+                    }
+                }
+
+                let _ = writeln!(output, "::endgroup::");
+            }
+        }
+    }
+
+    if let Some(commits_errors) = &results.commits_errors {
+        for commits_error in &commits_errors.errors {
+            match commits_error {
+                CommitsError::MaxCommitsExceeded {
+                    max_commits,
+                    actual_commits,
+                } => {
+                    let _ = writeln!(
+                        output,
+                        "::error title=Max Commits Exceeded::Maximum commits exceeded: found {actual_commits} commits, but maximum allowed is {max_commits}."
+                    );
+                }
+            }
+        }
+    }
+
+    output
+}

src/linting_results/mod.rs

@@ -2,19 +2,18 @@ use std::collections::{HashMap, VecDeque};
 
 use crate::commits::commit::Commit;
 
+mod github_actions;
 mod pretty;
 
 /// The representation of an error that an individual commit can have.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub enum CommitError {
-    /// Commit is a merge commit (has multiple parents).
     MergeCommit,
 }
 
 /// The representation of an error for the collection of commits as a whole.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum CommitsError {
-    /// The number of commits exceeds the maximum allowed.
     MaxCommitsExceeded {
         max_commits: usize,
         actual_commits: usize,
@@ -51,8 +50,11 @@ pub struct LintingResults {
 }
 
 impl LintingResults {
-    /// Get a pretty representation of the linting results as a string, suitable as output for a user.
     pub fn pretty(&self) -> String {
         pretty::print_all(self)
     }
+
+    pub fn github_actions(&self) -> String {
+        github_actions::print_all(self)
+    }
 }

src/main.rs

@@ -33,7 +33,7 @@ pub(crate) struct Arguments {
     #[arg(
         long,
         default_value = "default",
-        help = "Specifies the format for outputting results, acceptable values are quiet, default, and pretty."
+        help = "Specifies the format for outputting results, acceptable values are quiet, default, pretty, and github."
     )]
     pub(crate) output: Output,
 
@@ -79,6 +79,9 @@ fn run(arguments: Arguments) -> Result<i32> {
             Output::Pretty => {
                 println!("{}", linting_results.pretty());
             }
+            Output::GitHub => {
+                println!("{}", linting_results.github_actions());
+            }
         }
 
         // As we don't want an error printed but linting failed so want to exit unsuccessfully.

src/output.rs

@@ -5,4 +5,6 @@ pub enum Output {
     Quiet,
     Default,
     Pretty,
+    #[value(name = "github")]
+    GitHub,
 }