📦 deps(thirdparty): update snapshots

2026-07-01 16:02:41 +00:00
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+# Advanced Debugging Techniques
+
+## When the Program Hangs
+
+When a program runs but never returns, that *is* information — something is stuck. Don't guess; interrupt
+and observe.
+
+```
+Bug: program hangs (infinite loop or deadlock)
+
+→ dap pause                         ← interrupt wherever it is (returns OK immediately)
+  [the already-blocking debug/continue/step call returns auto-context: location + locals]
+  Stopped at process() · worker.py:55, locals: i=99999
+→ dap threads                       ← are other threads blocked too?
+→ dap eval "lock.locked()"          ← test deadlock hypothesis
+Root cause: lock never released. Fix → dap stop.
+```
+
+Check: is it one thread stuck (infinite loop, blocking I/O), or are multiple threads waiting on each
+other (deadlock)? The location where `pause` stops is your first clue.
+
+## Digging Into Complex State
+
+When a variable is opaque or deeply nested, expand it: `dap inspect data --depth 2`.
+
+## Concurrency Bugs
+
+If state is wrong but the code path looks correct, consider: is another thread modifying state
+concurrently?
+
+**First move at any concurrent crash or hang:** run `dap threads`, then inspect every thread's stack with
+`dap thread <id>` — the thread causing the problem is often not the one currently stopped.
+
+- **Deadlock pattern**: two or more threads each waiting for a resource the other holds. Check thread
+  states to confirm.
+- **Race condition**: unexpected values that change between stops. Look for shared mutable state
+  accessed without synchronization.
+
+## Bisecting Loops (Wolf Fence)
+
+A loop goes wrong at an unknown iteration. Binary search it:
+
+```
+dap debug app.py --break "app.py:45:i == 500"   # midpoint of 1000
+→ dap eval "is_valid(result)"                    # True → bug is after 500
+→ dap break add "app.py:45:i == 750"             # update the condition
+→ dap restart                                    # restart preserving new breakpoint
+```
+
+~10 iterations to find the bug in 1000. Not 1000 step commands.