[Open Wallet] click freeze system, when in sync node

[Saibato]

Steps to reproduce:
disconnect a full indexed node that has no "wallets" dir, in -datadir. and all node files in -datadir
wait until you missed say 20 or more new blocks.
A fast syncing high bandwide node might need a lag of more than 100
....
start the node with ui.
wait until IBD had set in..
click [Open Wallet] ....

If your whole system or VM ui enters an unresponsive state,
Don;t panic, brew a tee !!!. System should leave dead lock after < 5 min.
Close ui., hmm... 🤷‍♀️
In essence that is an edge case, but new users who first time try to do the right thing and run there full nodes
might run in this ...

refernced bitcoin/bitcoin#19419

EDIT: Note: even that fixed, the other freeze of window refresh, if re-scanning a wallet lag;s behind, is a different gui issue.to be solved in pipeline. ...
Upwards v0.18 ,19. 20 release to master you could get ui also in local temporary freeze, with -reindex or mine more than say 3117 blocks on a different node to an address of your test node and than connect to that mining node.
Unless you have a spared miner or to much btc, the preferred method to test is with regtest.

a="/tmp/test_a"
b="/tmp/test_b"
ca="-regtest -datadir=$a"
cb="-regtest -datadir=$b"
mkdir $a
mkdir $b
bitcoind -daemon $ca -server -datadir=$a
sleep 1
adr=$(bitcoin-cli  $ca getnewaddress) 
echo $adr
bitcoin-cli $ca stop 
sleep 1
bitcoin-qt  $cb  -server -listen  -datadir=$b &
sleep 1
echo "wait for coins ... this could take some while to gen"
gen=$(bitcoin-cli $cb generatetoaddress 3117  $adr) 
# Now start the node, should instant frezze repaint update
bitcoin-qt  $ca -connect=127.0.0.1 -port=1234 -datadir=$a &
echo $gen

////
frezze b ?

  

So far observed in debian and lubuntu VM's

[hebasto]

Steps to reproduce:
disconnect a node that has no "wallets" dir, in -datadir.
wait until you missed say 20 new blocks.
start the node with ui.
click [Open Wallet] ....

If your whole system ui hangs.

Couldn't reproduce it. Using Linux Mint 20, Qt 5.12.8, master (4946400).

UPDATE: having a separated blocks directory

[Saibato]

Steps to reproduce:
disconnect a node that has no "wallets" dir, in -datadir.
wait until you missed say 20 new blocks.
start the node with ui.
click [Open Wallet] ....
If your whole system ui hangs.

Couldn't reproduce it. Using Linux Mint 20, Qt 5.12.8, master (4946400).

̶C̶o̶u̶l̶d̶ ̶o̶b̶v̶i̶o̶u̶s̶l̶y̶ ̶b̶e̶ ̶s̶y̶s̶t̶e̶m̶ ̶d̶e̶p̶e̶n̶d̶e̶n̶t̶,̶ ̶A̶n̶d̶ ̶m̶a̶y̶b̶e̶ ̶y̶o̶u̶ ̶h̶a̶v̶e̶ ̶t̶o̶ ̶s̶t̶a̶y̶ ̶o̶n̶l̶y̶ ̶a̶ ̶b̶i̶t̶ ̶s̶h̶o̶r̶t̶e̶r̶ ̶o̶n̶l̶i̶n̶e̶ ̶again to start sync and get height and then close the connection and restart with a proxy that yield to nowhere.
Important is that the node has some blocks to work on on disk to reach height.
̶I̶ ̶g̶u̶e̶s̶s̶ ̶i̶t̶ ̶a̶l̶s̶o̶ ̶c̶a̶n̶ ̶d̶e̶p̶e̶n̶d̶ ̶o̶n̶ ̶t̶h̶e̶ ̶f̶i̶l̶e̶s̶ ̶d̶r̶i̶v̶e̶r̶ ̶a̶n̶d̶ ̶f̶o̶r̶m̶a̶t̶ ̶a̶s̶ ̶w̶e̶l̶l̶.̶

BTW i use a full indexed node. When we look at #18095 your system where also not able to reproduce,
BTW. i tested #18095 also, but had no effect on my system, ec/eci was not even triggered.

I hesitate a bit to post my exact system config here, ping me for pm if you need it.

[Saibato]

@hebasto
tyi, a node of mine, compiled with no wallet, was free of this issue and synced fine in GUI with 21rc1
Wallets in core ( if hot ) are anyway not that smart to use with hot keys, but as long as we have that build in by default, maybe we should just warn newbe users of this ugly annoying behavior
Because I see not much what we can do, if the wallet support is compiled in?

I still can reproduce this issue with any version above 19 up to 21rc2. lower I had not tried.

[promag]

@Saibato what about bitcoin-cli listwalletdir, does it take too long?

[Saibato]

@promag

what about bitcoin-cli listwalletdir, does it take too long?

I had first thought that was the only reason and did a PR that skipped the dir traversal. btw merged only into knots
But there is a much harder freeze I did try to address here, if you want to sync a node with some dust test funds in it.
My workaround was to have two compiles, I have lingering offline test nodes that I sync to current top from time to time or before i want to do tx,, so i sync with the no wallet compile and
then start the default compile with my private patch that has also the non listwalldir traversal so it hangs not the GUI from that since i use no separate blocksdir.
I probably could do all that with cmdline but i like the gui since it has the convenient debug cmdline interface, so it would be nice if we or u would find a fix for this.