Debug a contract

Inside the console, you can use these debugging commands:

$ 
::trace (contract-call? .my-contract my-function)
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$ 
::debug (contract-call? .my-contract my-function)
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$ 
break my-functionCopy

Debug navigation commands:

• step or s - Step into
• finish or f - Step out
• next or n - Step over
• continue or c - Continue execution

Let's take the clarity_counter_ contract as an example:

(define-map Counters principal uint)

(define-read-only (get-count (who principal))
  (default-to u0 (map-get? Counters who))
)

(define-public (count-up)
  (ok (map-set Counters tx-sender (+ (get-count tx-sender) u1)))
)

Trace

The ::trace command expects an expression, so make a contract-call? with our count-up function and see what happens.

$ 
::trace (contract-call? .counter count-up)
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[show output]

Breakpoints

You can also set a breakpoint at a specific line to better understand what's happening in your contract.

With ::debug, you can add breakpoints at a specific line of a contract or function to better understand what's happening in your contracts.

(define-map Counters principal uint)

(define-read-only (get-count (who principal))
  (default-to u0 (map-get? Counters who))
)

(define-public (count-up)
  (ok (map-set Counters tx-sender (+ (get-count tx-sender) u1)))
)

(define-public (count-twice)
  (double)
)

(define-private (double)
  (begin
    (unwrap-panic (count-up))
    (count-up)
  )
)

$ 
::debug (contract-call? .counter count-twice)
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$ 
break count-upCopy

Using the continue command, the breakpoint you set in the double function will trigger twice due to two count-up calls, which enables you to do variable and map analysis.

Next steps