From f07749e1592ea93ec73137c7d2c306de0405ac79 Mon Sep 17 00:00:00 2001 From: Simon Michael Date: Wed, 1 May 2024 17:39:33 -1000 Subject: [PATCH] ;doc: DEVFAQ: updates --- doc/DEVFAQ.md | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/doc/DEVFAQ.md b/doc/DEVFAQ.md index 50a8be5be..9d131c501 100644 --- a/doc/DEVFAQ.md +++ b/doc/DEVFAQ.md @@ -71,19 +71,18 @@ $ stack exec -- hledger --version And when you run at debug level -1, -2 or -3 the output should mention ghc-debug: ```cli $ hledger CMD --debug=-1 # run normally, and listen for ghc-debug commands -$ hledger CMD --debug=-2 # pause for ghc-debug commands at program start -$ hledger CMD --debug=-3 # pause for ghc-debug commands at program end +$ hledger CMD --debug=-2 # pause for ghc-debug commands at program start (doesn't work) +$ hledger CMD --debug=-3 # pause for ghc-debug commands at program end (doesn't work) Starting ghc-debug on socket: ... ``` -Now in another window, you can run [ghc-debug-brick](https://hackage.haskell.org/package/ghc-debug-brick) and it will show the hledger process (until it ends). Press enter to connect. This is not robust. Tips: +Now in another window, you can run [ghc-debug-brick](https://hackage.haskell.org/package/ghc-debug-brick) and it will show the hledger process (until it ends). Press enter to connect. If it fails, - you might need to clear out stale sockets: `rm -f ~/.local/share/ghc-debug/debuggee/sockets/*` - you might need to kill stale hledger processes: `pkill -fl hledger` -- with --debug=-2 or -3 it might fail with this error, reasons unclear:\ - `rts_resume: called from a different OS thread than rts_pause`.\ - To work around, use --debug=-1. - (This works best with hledger-ui or hledger-web; with hledger, you'll need to give it a big enough data file so that you can connect and pause it before it finishes.) -- once connected, if the program is running, press `p` to pause it +- with --debug=-2 or -3 it fails with `rts_resume: called from a different OS thread than rts_pause`, + so use --debug=-1 instead. This works best with the long-running hledger-ui or hledger-web; + with hledger, you'll need a big enough data file so that you have time to connect before it finishes. + Once connected, press `p` to pause the program. At this point, you can explore memory/profile information, save snapshots, resume execution, etc.