Make async stacktraces less verbose (#21091)

* Name iterators something human readable

Remove intermediate async procs from stacktraces

Clean async traceback message from reraises message

* Remove unused import/variable

* Fix failing tests

Don't add {.stackTrace: off.} to anonymous procs (They already don't appear in stacktrace)

* Fix failing tests in pragma category

Now check that the nim is a routine type first so we don't run into any assertion defects

* Hide stack trace pragma in docs and update doc tests

User doesn't need to know if something won't appear so this more becomes verbose noise

If this is a bad idea we can always add a `when defined(nimdoc)` switch so we don't add {.stackTrace: off.} to the Future[T] returning proc for docs

compiler/renderer.nim

@@ -619,7 +619,9 @@ proc isHideable(config: ConfigRef, n: PNode): bool =
   # xxx compare `ident` directly with `getIdent(cache, wRaises)`, but
   # this requires a `cache`.
   case n.kind
-  of nkExprColonExpr: result = n[0].kind == nkIdent and n[0].ident.s in ["raises", "tags", "extern", "deprecated", "forbids"]
+  of nkExprColonExpr:
+    result = n[0].kind == nkIdent and
+             n[0].ident.s.nimIdentNormalize in ["raises", "tags", "extern", "deprecated", "forbids", "stacktrace"]
   of nkIdent: result = n.ident.s in ["gcsafe", "deprecated"]
   else: result = false
 

lib/pure/asyncfutures.nim

@@ -329,29 +329,21 @@ proc `$`*(stackTraceEntries: seq[StackTraceEntry]): string =
     if leftLen > longestLeft:
       longestLeft = leftLen
 
-  var indent = 2
   # Format the entries.
   for entry in entries:
     let (filename, procname) = getFilenameProcname(entry)
 
-    if procname == "":
-      if entry.line == reraisedFromBegin:
-        result.add(spaces(indent) & "#[\n")
-        indent.inc(2)
-      elif entry.line == reraisedFromEnd:
-        indent.dec(2)
-        result.add(spaces(indent) & "]#\n")
-      continue
+    if procname == "" and entry.line == reraisedFromBegin:
+      break
 
     let left = "$#($#)" % [filename, $entry.line]
-    result.add((spaces(indent) & "$#$# $#\n") % [
+    result.add((spaces(2) & "$# $#\n") % [
       left,
-      spaces(longestLeft - left.len + 2),
       procname
     ])
     let hint = getHint(entry)
     if hint.len > 0:
-      result.add(spaces(indent+2) & "## " & hint & "\n")
+      result.add(spaces(4) & "## " & hint & "\n")
 
 proc injectStacktrace[T](future: Future[T]) =
   when not defined(release):

lib/pure/asyncmacro.nim

@@ -20,9 +20,8 @@ proc newCallWithLineInfo(fromNode: NimNode; theProc: NimNode, args: varargs[NimN
 template createCb(retFutureSym, iteratorNameSym,
                   strName, identName, futureVarCompletions: untyped) =
   bind finished
-
   var nameIterVar = iteratorNameSym
-  proc identName {.closure.} =
+  proc identName {.closure, stackTrace: off.} =
     try:
       if not nameIterVar.finished:
         var next = nameIterVar()
@@ -151,6 +150,10 @@ proc asyncSingleProc(prc: NimNode): NimNode =
       result[0][0] = quote do: Future[void]
     return result
 
+  if prc.kind in RoutineNodes and prc.name.kind != nnkEmpty:
+    # Only non anonymous functions need/can have stack trace disabled
+    prc.addPragma(nnkExprColonExpr.newTree(ident"stackTrace", ident"off"))
+
   if prc.kind notin {nnkProcDef, nnkLambda, nnkMethodDef, nnkDo}:
     error("Cannot transform this node kind into an async proc." &
           " proc/method definition or lambda node expected.", prc)
@@ -209,7 +212,7 @@ proc asyncSingleProc(prc: NimNode): NimNode =
   # ->   {.pop.}
   # ->   <proc_body>
   # ->   complete(retFuture, result)
-  var iteratorNameSym = genSym(nskIterator, $prcName & "Iter")
+  var iteratorNameSym = genSym(nskIterator, $prcName & " (Async)")
   var procBody = prc.body.processBody(retFutureSym, futureVarIdents)
   # don't do anything with forward bodies (empty)
   if procBody.kind != nnkEmpty:
@@ -251,9 +254,10 @@ proc asyncSingleProc(prc: NimNode): NimNode =
     # friendlier stack traces:
     var cbName = genSym(nskProc, prcName & NimAsyncContinueSuffix)
     var procCb = getAst createCb(retFutureSym, iteratorNameSym,
-                         newStrLitNode(prcName),
-                         cbName,
-                         createFutureVarCompletions(futureVarIdents, nil))
+                          newStrLitNode(prcName),
+                          cbName,
+                          createFutureVarCompletions(futureVarIdents, nil)
+                        )
     outerProcBody.add procCb
 
     # -> return retFuture

nimdoc/testproject/expected/testproject.html

@@ -503,7 +503,8 @@ <h1><a class="toc-backref" href="#12">Procs</a></h1>
 </div>
 <div id="asyncFun1-procs-all">
   <div id="asyncFun1">
-  <dt><pre><span class="Keyword">proc</span> <a href="#asyncFun1"><span class="Identifier">asyncFun1</span></a><span class="Other">(</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">Future</span><span class="Other">[</span><span class="Identifier">int</span><span class="Other">]</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">Exception</span><span class="Other">,</span> <span class="Identifier">ValueError</span><span class="Other">]</span><span class="Other">,</span>
+  <dt><pre><span class="Keyword">proc</span> <a href="#asyncFun1"><span class="Identifier">asyncFun1</span></a><span class="Other">(</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">Future</span><span class="Other">[</span><span class="Identifier">int</span><span class="Other">]</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">stackTrace</span><span class="Other">:</span> <span class="DecNumber">false</span><span class="Other">,</span>
+                                <span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">Exception</span><span class="Other">,</span> <span class="Identifier">ValueError</span><span class="Other">]</span><span class="Other">,</span>
                                 <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">RootEffect</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
   <dd>
 
@@ -515,8 +516,8 @@ <h1><a class="toc-backref" href="#12">Procs</a></h1>
 </div>
 <div id="asyncFun2-procs-all">
   <div id="asyncFun2">
-  <dt><pre><span class="Keyword">proc</span> <a href="#asyncFun2"><span class="Identifier">asyncFun2</span></a><span class="Other">(</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">owned</span><span class="Other">(</span><span class="Identifier">Future</span><span class="Other">[</span><span class="Identifier">void</span><span class="Other">]</span><span class="Other">)</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">Exception</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">RootEffect</span><span class="Other">]</span><span class="Other">,</span>
-                                        <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
+  <dt><pre><span class="Keyword">proc</span> <a href="#asyncFun2"><span class="Identifier">asyncFun2</span></a><span class="Other">(</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">owned</span><span class="Other">(</span><span class="Identifier">Future</span><span class="Other">[</span><span class="Identifier">void</span><span class="Other">]</span><span class="Other">)</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">stackTrace</span><span class="Other">:</span> <span class="DecNumber">false</span><span class="Other">,</span> <span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">Exception</span><span class="Other">]</span><span class="Other">,</span>
+                                        <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">RootEffect</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
   <dd>
 
 
@@ -527,8 +528,8 @@ <h1><a class="toc-backref" href="#12">Procs</a></h1>
 </div>
 <div id="asyncFun3-procs-all">
   <div id="asyncFun3">
-  <dt><pre><span class="Keyword">proc</span> <a href="#asyncFun3"><span class="Identifier">asyncFun3</span></a><span class="Other">(</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">owned</span><span class="Other">(</span><span class="Identifier">Future</span><span class="Other">[</span><span class="Identifier">void</span><span class="Other">]</span><span class="Other">)</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">Exception</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">RootEffect</span><span class="Other">]</span><span class="Other">,</span>
-                                        <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
+  <dt><pre><span class="Keyword">proc</span> <a href="#asyncFun3"><span class="Identifier">asyncFun3</span></a><span class="Other">(</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">owned</span><span class="Other">(</span><span class="Identifier">Future</span><span class="Other">[</span><span class="Identifier">void</span><span class="Other">]</span><span class="Other">)</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">stackTrace</span><span class="Other">:</span> <span class="DecNumber">false</span><span class="Other">,</span> <span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">Exception</span><span class="Other">]</span><span class="Other">,</span>
+                                        <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">RootEffect</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
   <dd>
 
 

tests/async/tasync_gcunsafe.nim

@@ -1,5 +1,5 @@
 discard """
-  errormsg: "'anotherGCSafeAsyncProcIter' is not GC-safe as it calls 'asyncGCUnsafeProc'"
+  errormsg: "'anotherGCSafeAsyncProc (Async)' is not GC-safe as it calls 'asyncGCUnsafeProc'"
   cmd: "nim c --threads:on $file"
   file: "asyncmacro.nim"
 """

tests/async/tasync_traceback.nim

@@ -67,51 +67,22 @@ import re
 const expected = """
 b failure
 Async traceback:
-  tasync_traceback\.nim\(\d+?\)\s+?tasync_traceback
-  asyncmacro\.nim\(\d+?\)\s+?a
-  asyncmacro\.nim\(\d+?\)\s+?aNimAsyncContinue
-    ## Resumes an async procedure
-  tasync_traceback\.nim\(\d+?\)\s+?aIter
-  asyncmacro\.nim\(\d+?\)\s+?b
-  asyncmacro\.nim\(\d+?\)\s+?bNimAsyncContinue
-    ## Resumes an async procedure
-  tasync_traceback\.nim\(\d+?\)\s+?bIter
-  #\[
-    tasync_traceback\.nim\(\d+?\)\s+?tasync_traceback
-    asyncmacro\.nim\(\d+?\)\s+?a
-    asyncmacro\.nim\(\d+?\)\s+?aNimAsyncContinue
-      ## Resumes an async procedure
-    asyncmacro\.nim\(\d+?\)\s+?aIter
-    asyncfutures\.nim\(\d+?\)\s+?read
-  \]#
+  tasync_traceback\.nim\(\d+?\) tasync_traceback
+  tasync_traceback\.nim\(\d+?\) a \(Async\)
+  tasync_traceback\.nim\(\d+?\) b \(Async\)
 Exception message: b failure
 
 
 bar failure
 Async traceback:
-  tasync_traceback\.nim\(\d+?\)\s+?tasync_traceback
-  asyncdispatch\.nim\(\d+?\)\s+?waitFor
-  asyncdispatch\.nim\(\d+?\)\s+?poll
+  tasync_traceback\.nim\(\d+?\) tasync_traceback
+  asyncdispatch\.nim\(\d+?\) waitFor
+  asyncdispatch\.nim\(\d+?\) poll
     ## Processes asynchronous completion events
-  asyncdispatch\.nim\(\d+?\)\s+?runOnce
-  asyncdispatch\.nim\(\d+?\)\s+?processPendingCallbacks
+  asyncdispatch\.nim\(\d+?\) runOnce
+  asyncdispatch\.nim\(\d+?\) processPendingCallbacks
     ## Executes pending callbacks
-  asyncmacro\.nim\(\d+?\)\s+?barNimAsyncContinue
-    ## Resumes an async procedure
-  tasync_traceback\.nim\(\d+?\)\s+?barIter
-  #\[
-    tasync_traceback\.nim\(\d+?\)\s+?tasync_traceback
-    asyncdispatch\.nim\(\d+?\)\s+?waitFor
-    asyncdispatch\.nim\(\d+?\)\s+?poll
-      ## Processes asynchronous completion events
-    asyncdispatch\.nim\(\d+?\)\s+?runOnce
-    asyncdispatch\.nim\(\d+?\)\s+?processPendingCallbacks
-      ## Executes pending callbacks
-    asyncmacro\.nim\(\d+?\)\s+?fooNimAsyncContinue
-      ## Resumes an async procedure
-    asyncmacro\.nim\(\d+?\)\s+?fooIter
-    asyncfutures\.nim\(\d+?\)\s+?read
-  \]#
+  tasync_traceback\.nim\(\d+?\) bar \(Async\)
 Exception message: bar failure
 
 """