AU: When checking if we've visited a file before, don't follow symlinks.

delta_performer_unittest.cc

 // Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <sys/mount.h>
 #include <inttypes.h>
 
 #include <algorithm>
 #include <string>
 #include <vector>
@@ skipping 242 matching lines @@
                                      b_mnt.c_str()).c_str()));
     EXPECT_TRUE(WriteSparseFile(StringPrintf("%s/fullsparse", b_mnt.c_str()),
                                 1024 * 1024));
     EXPECT_EQ(0, system(StringPrintf("dd if=/dev/zero of=%s/partsparese bs=1 "
                                      "seek=4096 count=1",
                                      b_mnt.c_str()).c_str()));
     EXPECT_EQ(0, system(StringPrintf("cp %s/srchardlink0 %s/tmp && "
                                      "mv %s/tmp %s/srchardlink1",
                                      b_mnt.c_str(), b_mnt.c_str(),
                                      b_mnt.c_str(), b_mnt.c_str()).c_str()));
+    EXPECT_EQ(0, system(StringPrintf("rm %s/boguslink && "
+                                     "echo foobar > %s/boguslink",
+                                     b_mnt.c_str(), b_mnt.c_str()).c_str()));
     EXPECT_TRUE(utils::WriteFile(StringPrintf("%s/hardtocompress",
                                               b_mnt.c_str()).c_str(),
                                  reinterpret_cast<const char*>(kRandomString),
                                  sizeof(kRandomString)));
   }
 
   string old_kernel;
   EXPECT_TRUE(utils::MakeTempFile("/tmp/old_kernel.XXXXXX", &old_kernel, NULL));
   ScopedPathUnlinker old_kernel_unlinker(old_kernel);
 
@@ skipping 257 matching lines @@
   op.clear_src_extents();
   *(op.add_src_extents()) = ExtentForRange(5, 3);
   EXPECT_TRUE(DeltaPerformer::IsIdempotentOperation(op));
   *(op.add_dst_extents()) = ExtentForRange(20, 6);
   EXPECT_TRUE(DeltaPerformer::IsIdempotentOperation(op));
   *(op.add_src_extents()) = ExtentForRange(19, 2);
   EXPECT_FALSE(DeltaPerformer::IsIdempotentOperation(op));
 }
 
 }  // namespace chromeos_update_engine