PsySH can automatically reload modified files during your session. When you edit a file externally and return to PsySH, changes are picked up without restarting.

Code reloading requires one of these extensions:

When supported, reloading is enabled automatically; no configuration needed.

Each time you enter input, PsySH checks timestamps of included files. Modified files are parsed and reloaded using uopz functions to update definitions in place.

• ✅ Method bodies (including private/protected)
• ✅ Function implementations (and new functions!)
• ✅ Class constants
• ✅ Global constants

• ❌ New class methods
• ❌ Class properties (adding/removing)
• ❌ Class inheritance or interfaces
• ❌ Method signatures (parameter types/counts)

For structural changes, you'll need to restart PsySH.

By default, PsySH skips reloading "risky" code patterns:

• Conditional definitions — Functions or constants defined inside if, while, for, etc. These may not match the conditions that existed when the file was first loaded.
• Static variables — Will reset to their initial values on reload (a warning is shown).
• Top-level side effects — Expressions, echo statements, etc. are not re-executed.

When code is skipped, you'll see a warning:

>>> my_helper()
Warning: Skipped conditional: if (...) { function my_helper() ... }

Use yolo to bypass safety checks and force-reload skipped code:

>>> yolo my_helper()
YOLO: Force-reloading ~/src/helpers.php
=> "result"

The !! shortcut repeats your last command:

>>> my_helper()
Warning: Skipped conditional: if (...) { function my_helper() ... }

>>> yolo !!
=> "result"

• Edit and test — Keep your editor and PsySH side by side for a tight feedback loop
• Watch for warnings — They indicate code that couldn't be fully reloaded
• Restart for big changes — Structural changes (new properties, inheritance) require a restart