Merge #17696: qt: Force set nPruneSize in QSettings after the intro dialog

af112ab62895b145660f4cd7ff842e9cfea2a530 qt: Rename SetPrune() to InitializePruneSetting() (Hennadii Stepanov)
b0bfbe50282877a1eee87118902901a280d6656d refactor: Drop `bool force' parameter (Hennadii Stepanov)
68c9bbe9bc91f882404556998666b1b5acea60e4 qt: Force set nPruneSize in QSettings after intro (Hennadii Stepanov)
a82bd8fa5708c16d1db3edc4e82d70788eb5af19 util: Replace magics with DEFAULT_PRUNE_TARGET_GB (Hennadii Stepanov)

Pull request description:

  On master (5622d8f3156a293e61d0964c33d4b21d8c9fd5e0), having `QSettings` set already
  ```
  $ grep nPruneSize ~/.config/Bitcoin/Bitcoin-Qt-testnet.conf
  nPruneSize=6
  ```

  enabling prune option in the intro dialog

  ```
  $ ./src/qt/bitcoin-qt -choosedatadir -testnet
  ```
  ![DeepinScreenshot_select-area_20191208120425](https://user-images.githubusercontent.com/32963518/70388183-eed68580-19b6-11ea-9aa1-f9ad9aaa68a6.png)

  has no effect:
  ```
  $ grep Prune ~/.bitcoin/testnet3/debug.log
  2019-12-08T10:04:41Z Prune configured to target 5722 MiB on disk for block and undo files.
  ```

  ---

  With this PR:
  ```
  $ grep Prune ~/.bitcoin/testnet3/debug.log
  2019-12-08T10:20:35Z Prune configured to target 1907 MiB on disk for block and undo files.
  ```

  This PR has been split of #17453 (the first two commits) as it fixes an orthogonal bug.

  Refs:
  - https://github.com/bitcoin/bitcoin/pull/17453#discussion_r345424240
  - https://github.com/bitcoin/bitcoin/pull/17453#discussion_r350960201

ACKs for top commit:
  Sjors:
    Code review re-ACK af112ab62895b145660f4cd7ff842e9cfea2a530
  ryanofsky:
    Code review ACK af112ab62895b145660f4cd7ff842e9cfea2a530. Just suggested changes since last review (thanks!)
  promag:
    Tested ACK af112ab62895b145660f4cd7ff842e9cfea2a530. Latest suggestions and changes look good to me.

Tree-SHA512: 8ddad34b30dcc2cdcad6678ba8a0b36fa176e4e3465862ef6eee9be0f98d8146705138c9c7995dd8c0990af41078ca743fef1a90ed9240081f052f32ddec72b9

1 files changed, 6 insertions, 3 deletions

diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
index 7a838d0848..22a1dacab0 100644
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -281,8 +281,11 @@ void BitcoinApplication::parameterSetup()
     m_node.initParameterInteraction();
 }
 
-void BitcoinApplication::SetPrune(bool prune, bool force) {
-     optionsModel->SetPrune(prune, force);
+void BitcoinApplication::InitializePruneSetting(bool prune)
+{
+    // If prune is set, intentionally override existing prune size with
+    // the default size since this is called when choosing a new datadir.
+    optionsModel->SetPruneTargetGB(prune ? DEFAULT_PRUNE_TARGET_GB : 0, true);
 }
 
 void BitcoinApplication::requestInitialize()
@@ -562,7 +565,7 @@ int GuiMain(int argc, char* argv[])
 
     if (did_show_intro) {
         // Store intro dialog settings other than datadir (network specific)
-        app.SetPrune(prune, true);
+        app.InitializePruneSetting(prune);
     }
 
     if (gArgs.GetBoolArg("-splash", DEFAULT_SPLASHSCREEN) && !gArgs.GetBoolArg("-min", false))