prompt: reduce false positives + add pre-push hook

.pre-commit-hooks.yaml

@@ -0,0 +1,19 @@
+# Pre-commit hook for code-reviewer.
+# See: https://pre-commit.com
+# Usage in .pre-commit-config.yaml:
+#
+#   - repo: https://github.com/OpticDiff/code-reviewer
+#     rev: v0.6.0
+#     hooks:
+#       - id: code-review
+#         stages: [pre-push]
+#         args: [--min-severity, high]
+#
+- id: code-review
+  name: code-review
+  description: AI-powered code review before push
+  entry: code-reviewer --diff
+  language: golang
+  pass_filenames: false
+  stages: [pre-push]
+  always_run: true

cmd/code-reviewer/main.go

@@ -12,6 +12,7 @@ import (
 	"github.com/OpticDiff/code-reviewer/internal/config"
 	ctxpkg "github.com/OpticDiff/code-reviewer/internal/context"
 	"github.com/OpticDiff/code-reviewer/internal/gitlab"
+	"github.com/OpticDiff/code-reviewer/internal/hook"
 	"github.com/OpticDiff/code-reviewer/internal/model"
 	"github.com/OpticDiff/code-reviewer/internal/reviewer"
 )
@@ -28,6 +29,15 @@ func main() {
 		}
 	}
 
+	// Handle "hook" subcommand before config.Load() since it doesn't need model config.
+	if len(os.Args) >= 2 && os.Args[1] == "hook" {
+		if err := runHook(os.Args[2:]); err != nil {
+			fmt.Fprintf(os.Stderr, "error: %v\n", err)
+			os.Exit(1)
+		}
+		os.Exit(0)
+	}
+
 	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
 		Level: slog.LevelInfo,
 	})))
@@ -152,3 +162,18 @@ func wrapProviderError(err error) error {
 	}
 	return fmt.Errorf("initializing model provider: %w", err)
 }
+
+// runHook dispatches hook subcommands.
+func runHook(args []string) error {
+	if len(args) == 0 {
+		return fmt.Errorf("usage: code-reviewer hook <install|uninstall>")
+	}
+	switch args[0] {
+	case "install":
+		return hook.Install()
+	case "uninstall":
+		return hook.Uninstall()
+	default:
+		return fmt.Errorf("unknown hook command: %q (valid: install, uninstall)", args[0])
+	}
+}

internal/hook/hook.go

@@ -0,0 +1,127 @@
+// Package hook provides git hook installation for code-reviewer.
+package hook
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// managedSentinel is the exact marker that identifies hooks managed by code-reviewer.
+// Ownership checks match this sentinel, not a loose substring, so a foreign hook
+// that happens to mention "code-reviewer" in a comment is never overwritten.
+const managedSentinel = "# managed-by: code-reviewer"
+
+const preCommitHookContent = `#!/bin/sh
+` + managedSentinel + `
+# code-reviewer pre-push hook
+# Installed by: code-reviewer hook install
+# Remove with:  code-reviewer hook uninstall
+#
+# This hook reviews your changes before pushing.
+# To skip: git push --no-verify
+
+set -e
+
+# Only run if there are commits to push.
+if ! git diff --quiet @{push} 2>/dev/null; then
+    echo "🔍 code-reviewer: reviewing changes before push..."
+    code-reviewer --diff --min-severity high --no-color
+fi
+`
+
+// Install writes the pre-push hook to the repository's hooks directory.
+// If a hook already exists and wasn't installed by code-reviewer, it returns an error.
+func Install() error {
+	hooksDir, err := resolveHooksDir()
+	if err != nil {
+		return err
+	}
+
+	hookPath := filepath.Join(hooksDir, "pre-push")
+
+	// Check for existing hook.
+	if data, err := os.ReadFile(hookPath); err == nil {
+		if !strings.Contains(string(data), managedSentinel) {
+			return fmt.Errorf("pre-push hook already exists at %s\n\nTo overwrite, remove it first:\n  rm %s", hookPath, hookPath)
+		}
+		// Our hook — safe to overwrite.
+	}
+
+	// Ensure hooks directory exists.
+	if err := os.MkdirAll(hooksDir, 0o755); err != nil {
+		return fmt.Errorf("creating hooks directory: %w", err)
+	}
+
+	if err := os.WriteFile(hookPath, []byte(preCommitHookContent), 0o755); err != nil {
+		return fmt.Errorf("writing pre-push hook: %w", err)
+	}
+
+	fmt.Printf("✅ Installed pre-push hook at %s\n", hookPath)
+	fmt.Println("   Reviews will run automatically on git push.")
+	fmt.Println("   Skip with: git push --no-verify")
+	return nil
+}
+
+// Uninstall removes the pre-push hook if it was installed by code-reviewer.
+func Uninstall() error {
+	hooksDir, err := resolveHooksDir()
+	if err != nil {
+		return err
+	}
+
+	hookPath := filepath.Join(hooksDir, "pre-push")
+
+	data, err := os.ReadFile(hookPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			fmt.Println("No pre-push hook found.")
+			return nil
+		}
+		return fmt.Errorf("reading hook: %w", err)
+	}
+
+	if !strings.Contains(string(data), managedSentinel) {
+		return fmt.Errorf("pre-push hook at %s was not installed by code-reviewer; refusing to remove", hookPath)
+	}
+
+	if err := os.Remove(hookPath); err != nil {
+		return fmt.Errorf("removing hook: %w", err)
+	}
+
+	fmt.Printf("✅ Removed pre-push hook from %s\n", hookPath)
+	return nil
+}
+
+// resolveHooksDir returns the hooks directory for the current repository,
+// honoring Git's core.hooksPath configuration if set.
+func resolveHooksDir() (string, error) {
+	// Try core.hooksPath first.
+	cmd := exec.Command("git", "rev-parse", "--git-path", "hooks")
+	out, err := cmd.Output()
+	if err == nil {
+		resolved := strings.TrimSpace(string(out))
+		if resolved != "" {
+			return resolved, nil
+		}
+	}
+
+	// Fallback: <gitdir>/hooks.
+	gitDir, err := findGitDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(gitDir, "hooks"), nil
+}
+
+// findGitDir locates the .git directory by running git rev-parse.
+func findGitDir() (string, error) {
+	cmd := exec.Command("git", "rev-parse", "--git-dir")
+	out, err := cmd.Output()
+	if err != nil {
+		return "", fmt.Errorf("not a git repository (run this from inside a git repo): %w", err)
+	}
+	return strings.TrimSpace(string(out)), nil
+}