Add package manager parsers (npm, pip, go, cargo)

src/depcheck/parsers/go.py

@@ -0,0 +1,59 @@
+"""Go go.mod parser."""
+
+import re
+from pathlib import Path
+
+from depcheck.models import Dependency, PackageManager
+from depcheck.parsers import Parser
+from depcheck.utils import parse_version_string
+
+
+class GoParser(Parser):
+    """Parser for Go go.mod files."""
+
+    package_manager = PackageManager.GO
+
+    def supports_file(self, file_path: Path) -> bool:
+        return file_path.name == "go.mod"
+
+    def get_file_patterns(self) -> list[str]:
+        return ["go.mod"]
+
+    def parse(self, file_path: Path) -> list[Dependency]:
+        dependencies: list[Dependency] = []
+
+        try:
+            content = file_path.read_text()
+        except OSError:
+            return dependencies
+
+        in_require_block = False
+        for line in content.splitlines():
+            line = line.strip()
+
+            if line.startswith("require ("):
+                in_require_block = True
+                continue
+            elif line == ")":
+                in_require_block = False
+                continue
+
+            if in_require_block or line.startswith("require "):
+                match = re.match(r"^(?:require\s+)?([^\s]+)\s+(.+)$", line)
+                if match:
+                    name = match.group(1)
+                    version = match.group(2).strip()
+
+                    version = parse_version_string(version)
+                    if version and not name.startswith("="):
+                        dependencies.append(
+                            Dependency(
+                                name=name,
+                                current_version=version,
+                                package_manager=self.package_manager,
+                                category="dependencies",
+                                source_file=str(file_path),
+                            )
+                        )
+
+        return dependencies