Merge #20080: Strip any trailing `/` in -datadir and -blocksdir paths

ad5cef5dfdd5802fc187a52e74d940a52f420a51 doc: Update data directory path comments (Hennadii Stepanov)
b19e88230f0e93e95e883e65376963cb9c36f606 util: Add StripRedundantLastElementsOfPath function (Hennadii Stepanov)

Pull request description:

  Wallet names in `listwalletdir` RPC are correct now, even if the `-datadir` path has any number of trailing `/`.

  This PR is an alternative to #19933.

  Fixes #19928.

ACKs for top commit:
  MarcoFalke:
    review ACK ad5cef5dfd 🔙
  promag:
    Code review ACK ad5cef5dfdd5802fc187a52e74d940a52f420a51.
  meshcollider:
    Code review + test run ACK ad5cef5dfdd5802fc187a52e74d940a52f420a51

Tree-SHA512: bccabbd6c18243d48d15b2b27201cc0f5984623dcbc635c8740cf74523f359844c36eadd40391142874fcf452a43880bb6afbf89815ae736e499f9a98143a661

2 files changed, 43 insertions, 6 deletions

diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 241c56934e..010b6adf1f 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -42,6 +42,28 @@ namespace BCLog {
 
 BOOST_FIXTURE_TEST_SUITE(util_tests, BasicTestingSetup)
 
+BOOST_AUTO_TEST_CASE(util_datadir)
+{
+    ClearDatadirCache();
+    const fs::path dd_norm = GetDataDir();
+
+    gArgs.ForceSetArg("-datadir", dd_norm.string() + "/");
+    ClearDatadirCache();
+    BOOST_CHECK_EQUAL(dd_norm, GetDataDir());
+
+    gArgs.ForceSetArg("-datadir", dd_norm.string() + "/.");
+    ClearDatadirCache();
+    BOOST_CHECK_EQUAL(dd_norm, GetDataDir());
+
+    gArgs.ForceSetArg("-datadir", dd_norm.string() + "/./");
+    ClearDatadirCache();
+    BOOST_CHECK_EQUAL(dd_norm, GetDataDir());
+
+    gArgs.ForceSetArg("-datadir", dd_norm.string() + "/.//");
+    ClearDatadirCache();
+    BOOST_CHECK_EQUAL(dd_norm, GetDataDir());
+}
+
 BOOST_AUTO_TEST_CASE(util_check)
 {
     // Check that Assert can forward
diff --git a/src/util/system.cpp b/src/util/system.cpp
index 9f8035948b..5f30136fa2 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -34,6 +34,7 @@
 #endif // __linux__
 
 #include <algorithm>
+#include <cassert>
 #include <fcntl.h>
 #include <sched.h>
 #include <sys/resource.h>
@@ -649,10 +650,9 @@ void PrintExceptionContinue(const std::exception* pex, const char* pszThread)
 
 fs::path GetDefaultDataDir()
 {
-    // Windows < Vista: C:\Documents and Settings\Username\Application Data\Bitcoin
-    // Windows >= Vista: C:\Users\Username\AppData\Roaming\Bitcoin
-    // Mac: ~/Library/Application Support/Bitcoin
-    // Unix: ~/.bitcoin
+    // Windows: C:\Users\Username\AppData\Roaming\Bitcoin
+    // macOS: ~/Library/Application Support/Bitcoin
+    // Unix-like: ~/.bitcoin
 #ifdef WIN32
     // Windows
     return GetSpecialFolderPath(CSIDL_APPDATA) / "Bitcoin";
@@ -664,15 +664,28 @@ fs::path GetDefaultDataDir()
     else
         pathRet = fs::path(pszHome);
 #ifdef MAC_OSX
-    // Mac
+    // macOS
     return pathRet / "Library/Application Support/Bitcoin";
 #else
-    // Unix
+    // Unix-like
     return pathRet / ".bitcoin";
 #endif
 #endif
 }
 
+namespace {
+fs::path StripRedundantLastElementsOfPath(const fs::path& path)
+{
+    auto result = path;
+    while (result.filename().string() == ".") {
+        result = result.parent_path();
+    }
+
+    assert(fs::equivalent(result, path));
+    return result;
+}
+} // namespace
+
 static fs::path g_blocks_path_cache_net_specific;
 static fs::path pathCached;
 static fs::path pathCachedNetSpecific;
@@ -700,6 +713,7 @@ const fs::path &GetBlocksDir()
     path /= BaseParams().DataDir();
     path /= "blocks";
     fs::create_directories(path);
+    path = StripRedundantLastElementsOfPath(path);
     return path;
 }
 
@@ -730,6 +744,7 @@ const fs::path &GetDataDir(bool fNetSpecific)
         fs::create_directories(path / "wallets");
     }
 
+    path = StripRedundantLastElementsOfPath(path);
     return path;
 }