Handle detached HEAD and initial commit (#25)

* Handle detached head and initial commit
* Add end-to-end test for detached head
* Update comments in the main file

Author: artem-y

cmd/commit/main.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/artem-y/commit/internal/config"
@@ -13,7 +14,6 @@ import (
 	"github.com/artem-y/commit/internal/user"
 
 	"github.com/go-git/go-git/v5"
-	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/object"
 )
 
@@ -47,36 +47,44 @@ func main() {
 		)
 	}
 
-	headRef := getCurrentHead(repo)
+	headFilePath := filepath.Join(
+		worktree.Filesystem.Root(),
+		".git",
+		"HEAD",
+	)
+
+	fileReader := config.FileReader{}
 
-	// Read branch name or HEAD
-	if headRef.Name().IsBranch() {
+	// Read current HEAD from file
+	headFile, _ := fileReader.ReadFile(headFilePath)
+	headFileText := string(headFile)
+
+	// If there is a branch name in the HEAD file, modify the commit message
+	if strings.HasPrefix(headFileText, helpers.HEAD_REF_PREFIX) {
+		branchName := strings.TrimPrefix(
+			headFileText,
+			helpers.HEAD_REF_PREFIX,
+		)
 
-		fileReader := config.FileReader{}
 		cfg, err := config.ReadCommitConfig(fileReader, configFilePath)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, helpers.Red("Failed to read config: %v\n"), err)
 			os.Exit(1)
 		}
 
 		messageGenerator := message_generator.MessageGenerator{
-			BranchName:  headRef.Name().Short(),
+			BranchName:  branchName,
 			UserMessage: commitMessage,
 			Config:      cfg,
 		}
 		commitMessage = messageGenerator.GenerateMessage()
+	}
 
-		if !dryRun {
-			commitChanges(repo, worktree, commitMessage)
-		}
-
-		fmt.Println(commitMessage)
-
-	} else if headRef.Name().IsTag() {
-		fmt.Printf("HEAD is a tag: %v\n", headRef.Name().Short())
-	} else {
-		fmt.Printf("Detached HEAD at %v\n", headRef.Hash())
+	if !dryRun {
+		commitChanges(repo, worktree, commitMessage)
 	}
+
+	fmt.Println(commitMessage)
 }
 
 // Reads commit message from command line arguments
@@ -104,16 +112,6 @@ func openRepo() *git.Repository {
 	return repo
 }
 
-// Reads the current HEAD reference
-func getCurrentHead(repo *git.Repository) *plumbing.Reference {
-	headRef, err := repo.Head()
-	if err != nil {
-		fmt.Fprintf(os.Stderr, helpers.Red("Failed to read current HEAD: %v\n"), err)
-		os.Exit(1)
-	}
-	return headRef
-}
-
 // Opens worktree
 func openWorktree(repo *git.Repository) *git.Worktree {
 	worktree, err := repo.Worktree()

e2e.sh

@@ -32,8 +32,7 @@ setup_test_repository() {
     git init && \
     # Set up local git config inside the new directory
     git config --local user.name "GitHub Actions CI Runner" && \
-    git config --local user.email "--" && \
-    touch file && git add file && git commit -m "Initial commit"
+    git config --local user.email "--"
 }
 
 start_test() {
@@ -251,6 +250,56 @@ test_use_config_with_empty_regex() {
 
 }
 
+test_commit_with_detached_head() {
+    TESTNAME="test_commit_with_detached_head"
+    start_test $TESTNAME
+
+    setup_test_repository &&\
+    git config --local advice.detachedHead false && \
+    git checkout -b feature/DEV-21-validation && \
+
+    # Write a config file
+    echo '
+    { 
+        "issueRegex": "DEV-[0-9]+",
+        "outputIssuePrefix": "",
+        "outputIssueSuffix": "",
+        "outputStringPrefix": "[",
+        "outputStringSuffix": "] "
+    }
+    ' > .commit.json && \
+
+    # Create the initial commit
+    echo "Hello, World!" > hello1 && \
+    git add hello1 && \
+    ../bin/commit "Initial commit" && \
+
+    # Create the second commit
+    touch hello2 && \
+    git add hello2 && \
+    ../bin/commit "Second commit" && \
+
+    # Checkout the previous commit
+    git checkout 'HEAD^' && \
+    
+    # Create commit with alternative changes
+    touch hello3 && \
+    git add hello3 && \
+    ../bin/commit "Alternative commit"
+
+    # Check if the commit was successful
+    if [ $? -ne 0 ]; then
+        fail_test $TESTNAME
+    fi
+
+    # Check if the commit message is correct
+    if [ "$(git log -1 --pretty=%B)" != 'Alternative commit' ]; then
+        fail_test $TESTNAME
+    fi
+
+    pass_test $TESTNAME
+}
+
 # MARK: - Run Tests
 
 build_if_needed
@@ -260,3 +309,4 @@ test_use_config_from_current_directory
 test_commit_from_subdirectory
 test_set_correct_author
 test_use_config_with_empty_regex
+test_commit_with_detached_head

internal/helpers/constants.go

@@ -7,4 +7,5 @@ const (
 	DEFAULT_OUTPUT_ISSUE_SUFFIX  = ""
 	DEFAULT_OUTPUT_STRING_PREFIX = ""
 	DEFAULT_OUTPUT_STRING_SUFFIX = ": "
+	HEAD_REF_PREFIX              = "ref: refs/heads/"
 )