Fix crash when calling absPath with empty input (#620)

Signed-off-by: Zhilei Ren <[email protected]>
Co-authored-by: Ian Chen <[email protected]>

Author: zhileiren

src/Filesystem.cc

@@ -135,7 +135,14 @@ std::string common::copyToUnixPath(const std::string &_path)
 /////////////////////////////////////////////////
 std::string common::absPath(const std::string &_path)
 {
-  return fs::absolute(_path).string();
+  std::error_code ec;
+  auto path = fs::absolute(_path, ec);
+  if (!fsWarn("absPath", ec))
+  {
+    path = "";
+  }
+
+  return path.string();
 }
 
 /////////////////////////////////////////////////

src/Filesystem_TEST.cc

@@ -636,3 +636,13 @@ TEST_F(FilesystemTest, separator)
   EXPECT_EQ("\\", gz::common::separator(""));
 #endif
 }
+
+/////////////////////////////////////////////////
+TEST_F(FilesystemTest, empty)
+{
+#ifdef __APPLE__
+  EXPECT_EQ(common::absPath(""), gz::common::cwd() + "/");
+#else
+  EXPECT_EQ(common::absPath(""), "");
+#endif
+}