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Paramless then catch #71

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6e58731
Better context param mismatch handling
TwitchBronBron Dec 19, 2025
4d90ca5
Merge branch 'master' of https://github.com/rokucommunity/promises in…
TwitchBronBron Dec 19, 2025
970eb1f
Refactor processPromiseListener to be a loop that tries combinations …
TwitchBronBron Dec 19, 2025
8eee30b
Merge branch 'master' of https://github.com/rokucommunity/promises in…
TwitchBronBron Dec 19, 2025
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199 changes: 104 additions & 95 deletions src/source/promises.bs
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Original file line number Diff line number Diff line change
Expand Up @@ -542,6 +542,12 @@ namespace promises.internal
promiseResultLowerCase = "promiseresult"
end enum

enum ListenerType
then = "then"
catch = "catch"
finally = "finally"
end enum

' Clear storage for a given promise
sub clearPromiseStorage(promise as object, nodeEvent = invalid as dynamic)
if nodeEvent <> invalid then
Expand Down Expand Up @@ -641,6 +647,7 @@ namespace promises.internal
print errorMessage
#end if
throw errorMessage
'bs:disable-next-line
return invalid
end function

Expand Down Expand Up @@ -668,17 +675,17 @@ namespace promises.internal

'handle .then() listeners
for each listener in promiseStorage.thenListeners
promises.internal.processPromiseListener(originalPromise, promiseState, listener, promiseState = promises.PromiseState.resolved, true, promiseResult)
promises.internal.processPromiseListener(originalPromise, promiseState, listener, promises.internal.ListenerType.then, promiseResult)
end for

'handle .catch() listeners
for each listener in promiseStorage.catchListeners
promises.internal.processPromiseListener(originalPromise, promiseState, listener, promiseState = promises.PromiseState.rejected, true, promiseResult)
promises.internal.processPromiseListener(originalPromise, promiseState, listener, promises.internal.ListenerType.catch, promiseResult)
end for

'handle .finally() listeners
for each listener in promiseStorage.finallyListeners
promises.internal.processPromiseListener(originalPromise, promiseState, listener, true, false, promiseResult)
promises.internal.processPromiseListener(originalPromise, promiseState, listener, promises.internal.ListenerType.finally, promiseResult)
end for
#if PROMISES_DEBUG
if m.__promises__debug = invalid then
Expand Down Expand Up @@ -715,121 +722,124 @@ namespace promises.internal
return (type(value) = "String" or type(value) = "roString") and value <> ""
end function

enum ArgCombination
none = 0
resultOnly = 1
resultAndContext = 2
contextOnly = 3
end enum

syntax error to prevent roku from running the code, cuz this is broken!

' Handle an individual promise listener
sub processPromiseListener(originalPromise as object, originalPromiseState as string, storageItem as object, callCallback as boolean, isThenOrCatch as boolean, promiseValue = invalid as dynamic)
sub processPromiseListener(originalPromise as object, originalPromiseState as string, storageItem as object, listenerType as promises.internal.ListenerType, promiseValue = invalid as dynamic)

newPromise = storageItem.promise
#if PROMISES_DEBUG
print "[promises.notify]", originalPromise.id, "notifying", newPromise.id
#end if
callback = storageItem.callback
context = storageItem.context
hasContext = promises.internal.isSet(context)
'only call the callback if configured to do so
'if we don't have a context, set it to a default value that might be used for recovery
if hasContext = false then
context = 0 ' 0 works for numbers, boolean, object, dynamic. (does not work for string or function, but those are uncommon)
end if

if listenerType = promises.internal.ListenerType.then then
callCallback = originalPromiseState = promises.PromiseState.resolved
if hasContext then
argFlows = [ArgCombination.resultAndContext, ArgCombination.resultOnly, ArgCombination.none]
else
argFlows = [ArgCombination.resultOnly, ArgCombination.resultAndContext, ArgCombination.none]
end if
else if listenerType = promises.internal.ListenerType.catch then
callCallback = originalPromiseState = promises.PromiseState.rejected
if hasContext then
argFlows = [ArgCombination.resultAndContext, ArgCombination.resultOnly, ArgCombination.none]
else
argFlows = [ArgCombination.resultOnly, ArgCombination.resultAndContext, ArgCombination.none]
end if
else 'listenerType === promises.internal.ListenerType.finally
callCallback = true
if hasContext then
argFlows = [ArgCombination.contextOnly, ArgCombination.none]
else
argFlows = [ArgCombination.none, ArgCombination.contextOnly]
end if
end if

callbackResult = invalid

if callCallback then
#if PROMISES_DEBUG
print "[promises.notify]", originalPromise.id, "calling callback for", newPromise.id
#end if
try
'.then and .catch take one or two parameters (`promiseValue` and optional `context`)
if isThenOrCatch then
if hasContext then
lineNumber = -1
try
lineNumber = LINE_NUM + 1
callbackResult = callback(promiseValue, context)
catch error
file = error.backtrace.peek()
if error.number = 241 and file.filename = promises.internal.getLibPath() and file.line_number = lineNumber then
#if PROMISES_SAVE_LISTENER_REGISTRATION_LOCATION
print "[promises.error]: " promises.internal.formatStackTrace(storageItem.registrationLocation, promises.internal.wrongNumberOfParametersMessage)
#else
print "[promises.error]: " promises.internal.formatStackTrace(error, promises.internal.wrongNumberOfParametersMessage)
#end if
callbackResult = callback(promiseValue)
else
promises.internal.logCrashIfEnabled(error)
callbackResult = promises.reject(error)
end if
end try
else
try
lineNumber = LINE_NUM + 1
callbackResult = callback(promiseValue)
catch error
file = error.backtrace.peek()
if error.number = 241 and file.filename = promises.internal.getLibPath() and file.line_number = lineNumber then
#if PROMISES_SAVE_LISTENER_REGISTRATION_LOCATION
print "[promises.error]: " promises.internal.formatStackTrace(storageItem.registrationLocation, promises.internal.wrongNumberOfParametersMessage)
#else
print "[promises.error]: " promises.internal.formatStackTrace(error, promises.internal.wrongNumberOfParametersMessage)
#end if
callbackResult = callback(promiseValue, 0) ' 0 works for numbers, boolean, object, dynamic. (does not work for string or function, but those are uncommon)
else
promises.internal.logCrashIfEnabled(error)
callbackResult = promises.reject(error)
end if
end try
end if

'.finally callback takes 1 optional parameter (`context`)
else
if hasContext then
lineNumber = -1
try
lineNumber = LINE_NUM + 1
callbackResult = callback(context)
catch error
file = error.backtrace.peek()
if error.number = 241 and file.filename = promises.internal.getLibPath() and file.line_number = lineNumber then
#if PROMISES_SAVE_LISTENER_REGISTRATION_LOCATION
print "[promises.error]: " promises.internal.formatStackTrace(storageItem.registrationLocation, promises.internal.wrongNumberOfParametersMessage)
#else
print "[promises.error]: " promises.internal.formatStackTrace(error, promises.internal.wrongNumberOfParametersMessage)
#end if
callbackResult = callback()
else
promises.internal.logCrashIfEnabled(error)
callbackResult = promises.reject(error)
end if
end try
lastSeenError = invalid
' try different arg combinations until one works. We'll try the most likely combinations first. These are defined above based on
' whether context is provided and which type of listener this is. Sometimes callbacks might accidentally define a param when they shouldn't,
' other times they forgot to define a param but it's required.
for each argFlow in argFlows
lineNumber = -1
try
if argFlow = ArgCombination.resultAndContext then
lineNumber = LINE_NUM + 1
callbackResult = callback(promiseValue, context)

else if argFlow = ArgCombination.resultOnly then
lineNumber = LINE_NUM + 1
callbackResult = callback(promiseValue)

else if argFlow = ArgCombination.contextOnly then
lineNumber = LINE_NUM + 1
callbackResult = callback(context)

else ' if argFlow = ArgCombination.none then
lineNumber = LINE_NUM + 1
callbackResult = callback()
end if
'we got a result. clear the error
lastSeenError = invalid
exit for
catch error
file = error.backtrace.peek()
lastSeenError = error
if error.number = 241 and file.filename = promises.internal.getLibPath() and file.line_number = lineNumber then
wrongNumberOfParametersMessage = "Wrong number of parameters defined for promise '" + listenerType + "' callback. We will attempt to recover, but performance will suffer if you don't fix the problem."
#if PROMISES_SAVE_LISTENER_REGISTRATION_LOCATION
print "[promises.error]: " promises.internal.formatStackTrace(storageItem.registrationLocation, wrongNumberOfParametersMessage)
#else
print "[promises.error]: " promises.internal.formatStackTrace(error, wrongNumberOfParametersMessage)
#end if
else
try
lineNumber = LINE_NUM + 1
callbackResult = callback()
catch error
file = error.backtrace.peek()
if error.number = 241 and file.filename = promises.internal.getLibPath() and file.line_number = lineNumber then
#if PROMISES_SAVE_LISTENER_REGISTRATION_LOCATION
print "[promises.error]: " promises.internal.formatStackTrace(storageItem.registrationLocation, promises.internal.wrongNumberOfParametersMessage)
#else
print "[promises.error]: " promises.internal.formatStackTrace(error, promises.internal.wrongNumberOfParametersMessage)
#end if
callbackResult = callback(0) ' 0 works for numbers, boolean, object, dynamic. (does not work for string or function, but those are uncommon)
else
promises.internal.logCrashIfEnabled(error)
callbackResult = promises.reject(error)
end if
end try
exit for ' some other error occurred, exit the loop and reject below
end if
end if
catch e
end try
end for

if lastSeenError <> invalid then
'if we get here and we still have an error, it means none of the arg combinations worked. Reject the error and let's move on.
#if PROMISES_DEBUG
print "[promises.notify]", originalPromise.id, "callback for", newPromise.id, "threw exception", e
#end if
promises.internal.logCrashIfEnabled(e)
promises.internal.logCrashIfEnabled(lastSeenError)
'the result is a rejected promise
callbackResult = promises.reject(e)
end try
else
'use the current promise value to pass to the next promise (this is a .catch handler)
callbackResult = promises.reject(lastSeenError)
end if


else 'if callCallback = false
'pass the promise value to the next promise (this is a .catch handler)
if originalPromiseState = promises.PromiseState.rejected then
callbackResult = promises.reject(promiseValue)
else
callbackResult = promiseValue
end if
end if

if isThenOrCatch then
'is `then` or `catch` listener
if not listenerType <> promises.internal.ListenerType.then then
'if the .then() callback returned a promise. wait for it to resolve and THEN resolve the newPromise
if promises.isPromise(callbackResult) then
callbackPromise = callbackResult
Expand Down Expand Up @@ -857,7 +867,8 @@ namespace promises.internal
else
promises.resolve(callbackResult, newPromise)
end if
else

else ' if listenerType = promises.internal.ListenerType.finally then
' This is a .finally() block
if promises.isPromise(callbackResult) then
callbackPromise = callbackResult
Expand Down Expand Up @@ -1119,8 +1130,6 @@ namespace promises.internal
return result
end function

const wrongNumberOfParametersMessage = "Wrong number of parameters in promise callback. We have recovered, but this should be fixed as performance will suffer."

' Returns a string representation of the stack trace
' example:
' Error: some error
Expand Down
3 changes: 0 additions & 3 deletions src/source/promises.spec.bs
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Original file line number Diff line number Diff line change
Expand Up @@ -1290,7 +1290,6 @@ namespace tests
end sub

@async
@only()
@it("recovers when did NOT send context, but DID define the parameter (testing multiple param types")
sub _()
getGlobalAA().myCount = 0
Expand Down Expand Up @@ -1370,7 +1369,6 @@ namespace tests
end sub

@async
@only()
@it("recovers when did NOT send context, but DID define the parameter (testing multiple param types")
sub _()
getGlobalAA().myCount = 0
Expand Down Expand Up @@ -1454,7 +1452,6 @@ namespace tests
end sub

@async
@only()
@it("recovers when did NOT send context, but DID define the parameter (testing multiple param types")
sub _()
getGlobalAA().myCount = 0
Expand Down
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