fork std/tasks, stricter exceptions (#34)

benchmarks/bouncing_producer_consumer/taskpool_bpc.nim

@@ -65,7 +65,7 @@ proc bpc_consume_nopoll(usec: int32) =
 
     dummy_cpt()
 
-proc bpc_produce(n, d: int32) {.gcsafe.} =
+proc bpc_produce(n, d: int32) {.gcsafe, raises: [].} =
   if d > 0:
     # Create producer task
     tp.spawn bpc_produce(n, d-1)

benchmarks/dfs/taskpool_dfs.nim

@@ -10,14 +10,14 @@ import
   system/ansi_c, strformat, os, strutils, cpuinfo,
   # Library
   ../../taskpools
-  
+
 when not defined(windows):
   # bench
   import ../wtime
 
 var tp: Taskpool
 
-proc dfs(depth, breadth: int): uint32 {.gcsafe.} =
+proc dfs(depth, breadth: int): uint32 {.gcsafe, raises: [].} =
   if depth == 0:
     return 1
 

benchmarks/heat/taskpool_heat.nim

@@ -5,6 +5,8 @@
 #   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
+{.push raises: [].}
+
 # From fibril
 #
 # Original license
@@ -251,18 +253,22 @@ proc verify() =
 
   me /= nx * ny
 
-  if mae > 1e-12:
-    echo &"Local maximal absolute error {mae:1.3e}"
-    quit 1
-  if mre > 1e-12:
-    echo &"Local maximal relative error {mre:1.3e}"
-    quit 1
-  if me > 1e-12:
-    echo &"Global mean absolute error {me:1.3e}"
-    quit 1
+  try:
+    if mae > 1e-12:
+      echo &"Local maximal absolute error {mae:1.3e}"
+      quit 1
+    if mre > 1e-12:
+      echo &"Local maximal relative error {mre:1.3e}"
+      quit 1
+    if me > 1e-12:
+      echo &"Global mean absolute error {me:1.3e}"
+      quit 1
+  except ValueError: raiseAssert "format strings"
 
   echo "Verification successful"
 
+{.pop.}
+
 proc main() =
   var nthreads: int
   if existsEnv"TASKPOOL_NUM_THREADS":

benchmarks/nqueens/taskpool_nqueens.nim

@@ -88,10 +88,10 @@ func isValid(n: int32, a: CharArray): bool =
   ## Returns true if none of the queens conflict and 0 otherwise.
 
   for i in 0'i32 ..< n:
-    let p = cast[int32](a[i])
+    let p = int32(a[i])
 
     for j in i+1 ..< n:
-      let q = cast[int32](a[j])
+      let q = int32(a[j])
       if q == p or q == p - (j-i) or q == p + (j-i):
         return false
   return true
@@ -111,7 +111,7 @@ proc nqueens_ser(n, j: int32, a: CharArray): int32 =
     if isValid(j+1, a):
       result += nqueens_ser(n, j+1, a)
 
-proc nqueens_par(n, j: int32, a: CharArray): int32 {.gcsafe.} =
+proc nqueens_par(n, j: int32, a: CharArray): int32 {.gcsafe, raises: [].} =
 
   if n == j:
     # Good solution, count it

examples/e01_simple_tasks.nim

@@ -3,8 +3,11 @@ import ../taskpools
 block: # Async without result
 
   proc displayInt(x: int) =
-    stdout.write(x)
-    stdout.write(" - SUCCESS\n")
+    try:
+      stdout.write(x)
+      stdout.write(" - SUCCESS\n")
+    except IOError:
+      quit 1 # can't do anything productive
 
   proc main() =
     echo "\nSanity check 1: Printing 123456 654321 in parallel"
@@ -21,7 +24,7 @@ block: # Async/Await
   var tp: Taskpool
 
 
-  proc asyncFib(n: int): int {.gcsafe.} =
+  proc asyncFib(n: int): int {.gcsafe, raises: [].} =
     if n < 2:
       return n
 

examples/e02_parallel_pi.nim

@@ -1,7 +1,7 @@
 # Demo of API using a very inefficient π approcimation algorithm.
 
 import
-  std/[strutils, math, cpuinfo],
+  std/[strutils, cpuinfo],
   ../taskpools
 
 # From https://github.com/nim-lang/Nim/blob/v1.6.2/tests/parallel/tpi.nim

taskpools/channels_spsc_single.nim

@@ -5,6 +5,8 @@
 #   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
+{.push raises: [].}
+
 import
   std/atomics,
   ./instrumentation/[contracts, loggers]
@@ -28,8 +30,6 @@ type
     itemSize*: uint8
     buffer*{.align: 8.}: UncheckedArray[byte]
 
-{.push raises: [AssertionDefect].} # Ensure no exceptions can happen
-
 proc `=`(
     dest: var ChannelSPSCSingle,
     source: ChannelSPSCSingle
@@ -78,7 +78,7 @@ func trySend*[T](chan: var ChannelSPSCSingle, src: sink T): bool {.inline.} =
   chan.full.store(true, moRelease)
   return true
 
-{.pop.} # raises: [AssertionDefect]
+{.pop.} # raises: []
 
 # Sanity checks
 # ------------------------------------------------------------------------------

taskpools/chase_lev_deques.nim

@@ -35,6 +35,8 @@
 # To reduce contention, stealing is done on the opposite end from push/pop
 # so that there is a race only for the very last task.
 
+{.push raises: [].} # Ensure no exceptions can happen
+
 import
   system/ansi_c,
   std/atomics,
@@ -65,7 +67,6 @@ type
     buf: Atomic[ptr Buf[T]]
     garbage: ptr Buf[T]
 
-{.push raises: [AssertionDefect].} # Ensure no exceptions can happen
 {.push overflowChecks: off.}       # We don't want exceptions (for Defect) in a multithreaded context
                                    # but we don't to deal with underflow of unsigned int either
                                    # say "if a < b - c" with c > b
@@ -192,4 +193,4 @@ proc steal*[T](deque: var ChaseLevDeque[T]): T =
       return default(T)
 
 {.pop.} # overflowChecks
-{.pop.} # raises: [AssertionDefect]
+{.pop.} # raises: []

taskpools/event_notifiers.nim

@@ -22,6 +22,8 @@
 # but requires the threadpool to be message-passing based.
 # https://github.com/mratsim/weave/blob/a230cce98a8524b2680011e496ec17de3c1039f2/weave/cross_thread_com/event_notifiers.nim
 
+{.push raises: [].} # Ensure no exceptions can happen
+
 import
   std/locks,
   ./instrumentation/contracts
@@ -36,7 +38,6 @@ type
     parked: int
     signals: int
 
-{.push raises: [AssertionDefect].} # Ensure no exceptions can happen
 {.push overflowChecks: off.}       # We don't want exceptions (for Defect) in a multithreaded context
                                    # but we don't to deal with underflow of unsigned int either
                                    # say "if a < b - c" with c > b

taskpools/flowvars.nim

@@ -5,8 +5,9 @@
 #   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
+{.push raises: [].}
+
 import
-  std/os,
   ./instrumentation/contracts,
   ./channels_spsc_single,
   ./primitives/allocs

taskpools/taskpools.nim

@@ -35,7 +35,7 @@
 # In case a thread is blocked for IO, other threads can steal pending tasks in that thread.
 # If all threads are pending for IO, the threadpool will not make any progress and be soft-locked.
 
-{.push raises: [AssertionDefect].} # Ensure no exceptions can happen
+{.push raises: [].} # Ensure no exceptions can happen
 
 import
   system/ansi_c,
@@ -47,14 +47,13 @@ import
   ./instrumentation/[contracts, loggers],
   ./sparsesets,
   ./flowvars,
-  ./ast_utils
+  ./ast_utils,
+  ./tasks
 
 export
   # flowvars
-  Flowvar, isSpawned, isReady, sync
+  Flowvar, isSpawned, isReady, sync, tasks
 
-import std/[isolation, tasks]
-export isolation
 
 type
   WorkerID = int32
@@ -182,7 +181,7 @@ proc new(T: type TaskNode, parent: TaskNode, task: sink Task): T =
   tn.task = task
   return tn
 
-proc runTask(tn: var TaskNode) {.raises:[Exception], inline.} =
+proc runTask(tn: var TaskNode) {.raises:[], inline.} =
   ## Run a task and consumes the taskNode
   tn.task.invoke()
   {.gcsafe.}: # Upstream missing tagging `=destroy` as gcsafe
@@ -245,7 +244,7 @@ const RootTask = default(Task) # TODO: sentinel value different from null task
 template isRootTask(task: Task): bool =
   task == RootTask
 
-proc forceFuture*[T](fv: Flowvar[T], parentResult: var T) {.raises:[Exception].} =
+proc forceFuture*[T](fv: Flowvar[T], parentResult: var T) {.raises:[].} =
   ## Eagerly complete an awaited FlowVar
 
   template ctx: untyped = workerContext