From ac8f6c57a1eb915e9b25ea52bf868c8b89b30c04 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oscar=20Nihlg=C3=A5rd?= <oscarnihlgard@gmail.com>
Date: Mon, 28 Jan 2019 17:18:07 +0100
Subject: [PATCH] Improve exception tracking in the streams module (#10453)

---
 changelog.md         |  2 ++
 lib/pure/streams.nim | 37 ++++++++++++++++---------------------
 2 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/changelog.md b/changelog.md
index eb97ac9a6f..85e06112bb 100644
--- a/changelog.md
+++ b/changelog.md
@@ -38,6 +38,8 @@
 
 - The procs `parseutils.parseBiggsetInt`, `parseutils.parseInt`, `parseutils.parseBiggestUInt` and `parseutils.parseUInt` now raise a `ValueError` when the parsed integer is outside of the valid range. Previously they sometimes raised a `OverflowError` and sometimes returned `0`.
 
+- `streams.StreamObject` now restricts its fields to only raise `system.Defect`, `system.IOError` and `system.OSError`. This change only affects custom stream implementations.
+
 - nre's `RegexMatch.{captureBounds,captures}[]`  no longer return `Option` or
   `nil`/`""`, respectivly. Use the newly added `n in p.captures` method to
   check if a group is captured, otherwise you'll recieve an exception.
diff --git a/lib/pure/streams.nim b/lib/pure/streams.nim
index 10de86e9f3..b6e77bbc02 100644
--- a/lib/pure/streams.nim
+++ b/lib/pure/streams.nim
@@ -45,17 +45,22 @@ type
                                  ## here shouldn't be used directly. They are
                                  ## accessible so that a stream implementation
                                  ## can override them.
-    closeImpl*: proc (s: Stream) {.nimcall, tags: [], gcsafe.}
-    atEndImpl*: proc (s: Stream): bool {.nimcall, tags: [], gcsafe.}
-    setPositionImpl*: proc (s: Stream, pos: int) {.nimcall, tags: [], gcsafe.}
-    getPositionImpl*: proc (s: Stream): int {.nimcall, tags: [], gcsafe.}
-    readDataImpl*: proc (s: Stream, buffer: pointer,
-                         bufLen: int): int {.nimcall, tags: [ReadIOEffect], gcsafe.}
-    peekDataImpl*: proc (s: Stream, buffer: pointer,
-                         bufLen: int): int {.nimcall, tags: [ReadIOEffect], gcsafe.}
-    writeDataImpl*: proc (s: Stream, buffer: pointer, bufLen: int) {.nimcall,
-      tags: [WriteIOEffect], gcsafe.}
-    flushImpl*: proc (s: Stream) {.nimcall, tags: [WriteIOEffect], gcsafe.}
+    closeImpl*: proc (s: Stream)
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [], gcsafe.}
+    atEndImpl*: proc (s: Stream): bool
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [], gcsafe.}
+    setPositionImpl*: proc (s: Stream, pos: int)
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [], gcsafe.}
+    getPositionImpl*: proc (s: Stream): int
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [], gcsafe.}
+    readDataImpl*: proc (s: Stream, buffer: pointer, bufLen: int): int
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [ReadIOEffect], gcsafe.}
+    peekDataImpl*: proc (s: Stream, buffer: pointer, bufLen: int): int
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [ReadIOEffect], gcsafe.}
+    writeDataImpl*: proc (s: Stream, buffer: pointer, bufLen: int)
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [WriteIOEffect], gcsafe.}
+    flushImpl*: proc (s: Stream)
+      {.nimcall, raises: [Defect, IOError, OSError], tags: [WriteIOEffect], gcsafe.}
 
 proc flush*(s: Stream) =
   ## flushes the buffers that the stream `s` might use.
@@ -65,10 +70,6 @@ proc close*(s: Stream) =
   ## closes the stream `s`.
   if not isNil(s.closeImpl): s.closeImpl(s)
 
-proc close*(s, unused: Stream) {.deprecated.} =
-  ## closes the stream `s`.
-  s.closeImpl(s)
-
 proc atEnd*(s: Stream): bool =
   ## checks if more data can be read from `f`. Returns true if all data has
   ## been read.
@@ -111,12 +112,6 @@ proc writeData*(s: Stream, buffer: pointer, bufLen: int) =
   ## to the stream `s`.
   s.writeDataImpl(s, buffer, bufLen)
 
-proc writeData*(s, unused: Stream, buffer: pointer,
-                bufLen: int) {.deprecated.} =
-  ## low level proc that writes an untyped `buffer` of `bufLen` size
-  ## to the stream `s`.
-  s.writeDataImpl(s, buffer, bufLen)
-
 proc write*[T](s: Stream, x: T) =
   ## generic write procedure. Writes `x` to the stream `s`. Implementation:
   ##