Merge bitcoin/bitcoin#24306: util: Make ArgsManager::GetPathArg more widely usable

60aa179d8f9a675efa2d78eaadc09e3ba450f50f Use GetPathArg where possible (Pavol Rusnak)
5b946edd73640c6ecdfb4cbac1d4351e634678dc util, refactor: Use GetPathArg to read "-settings" value (Ryan Ofsky)
687e655ae2970f2f13aca0267c7de86dc69be763 util: Add GetPathArg default path argument (Ryan Ofsky)

Pull request description:

  Improve `ArgsManager::GetPathArg` method added in recent PR #24265, so it is usable more places. This PR starts to use it for the `-settings` option. This can also be helpful for #24274 which is parsing more path options.

  - Add `GetPathArg` default argument so it is less awkward to use to parse options that have default values.
  - Fix `GetPathArg` negated argument handling. Return path{} not path{"0"} when path argument is negated.
  - Add unit tests for default and negated cases
  - Move `GetPathArg` method declaration next to `GetArg` declaration. The two methods are close substitutes for each, so this should help keep them consistent and make them more discoverable.

ACKs for top commit:
  w0xlt:
    Tested ACK 60aa179 on Ubuntu 21.10
  hebasto:
    re-ACK 60aa179d8f9a675efa2d78eaadc09e3ba450f50f

Tree-SHA512: 3d24b885d8bbeef39ea5d0556e2f09b9e5f4a21179cef11cbbbc1b84da29c8fb66ba698889054ce28d80bc25926687654c8532ed46054bf5b2dd1837866bd1cd

1 files changed, 2 insertions, 5 deletions

diff --git a/src/init.cpp b/src/init.cpp
index a3d53c3fae..3110797194 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -135,7 +135,7 @@ static const char* BITCOIN_PID_FILENAME = "bitcoind.pid";
 
 static fs::path GetPidFile(const ArgsManager& args)
 {
-    return AbsPathForConfigVal(fs::PathFromString(args.GetArg("-pid", BITCOIN_PID_FILENAME)));
+    return AbsPathForConfigVal(args.GetPathArg("-pid", BITCOIN_PID_FILENAME));
 }
 
 [[nodiscard]] static bool CreatePidFile(const ArgsManager& args)
@@ -1229,10 +1229,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         // Read asmap file if configured
         std::vector<bool> asmap;
         if (args.IsArgSet("-asmap")) {
-            fs::path asmap_path = fs::PathFromString(args.GetArg("-asmap", ""));
-            if (asmap_path.empty()) {
-                asmap_path = fs::PathFromString(DEFAULT_ASMAP_FILENAME);
-            }
+            fs::path asmap_path = args.GetPathArg("-asmap", DEFAULT_ASMAP_FILENAME);
             if (!asmap_path.is_absolute()) {
                 asmap_path = gArgs.GetDataDirNet() / asmap_path;
             }