Fix BytesIO.seek overloads

Src/IronPython.Modules/_bytesio.cs

@@ -253,14 +253,7 @@ public override List readlines([DefaultParameterValue(null)]object hint) {
                 return lines;
             }
 
-            [Documentation("seek(pos, whence=0) -> int.  Change stream position.\n\n"
-                + "Seek to byte offset pos relative to position indicated by whence:\n"
-                + "     0  Start of stream (the default).  pos should be >= 0;\n"
-                + "     1  Current position - pos may be negative;\n"
-                + "     2  End of stream - pos usually negative.\n"
-                + "Returns the new absolute position."
-                )]
-            public BigInteger seek(int pos, int whence = 0) {
+            private BigInteger seek(int pos, int whence) {
                 _checkClosed();
 
                 switch (whence) {
@@ -281,13 +274,16 @@ public BigInteger seek(int pos, int whence = 0) {
                 }
             }
 
-            public BigInteger seek(int pos, BigInteger whence) => seek(pos, (int)whence);
-
-            public BigInteger seek(int pos, double whence) => throw PythonOps.TypeError("integer argument expected, got float");
-
-            public BigInteger seek(double pos, [DefaultParameterValue(0)]object whence) => throw PythonOps.TypeError("'float' object cannot be interpreted as an index");
+            public BigInteger seek(double pos, [Optional]object whence) => throw PythonOps.TypeError("'float' object cannot be interpreted as an index");
 
-            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [DefaultParameterValue(0)]object whence) {
+            [Documentation("seek(pos, whence=0) -> int.  Change stream position.\n\n"
+                + "Seek to byte offset pos relative to position indicated by whence:\n"
+                + "     0  Start of stream (the default).  pos should be >= 0;\n"
+                + "     1  Current position - pos may be negative;\n"
+                + "     2  End of stream - pos usually negative.\n"
+                + "Returns the new absolute position."
+                )]
+            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [Optional]object whence) {
                 _checkClosed();
 
                 int posInt = (int)pos;
@@ -297,9 +293,9 @@ public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [Defau
                     case Extensible<int> v:
                         return seek(posInt, v);
                     case BigInteger v:
-                        return seek(posInt, v);
+                        return seek(posInt, (int)v);
                     case Extensible<BigInteger> v:
-                        return seek(posInt, v);
+                        return seek(posInt, (int)v.Value);
                     case double _:
                     case Extensible<double> _:
                         throw PythonOps.TypeError("integer argument expected, got float");

Src/IronPython.Modules/_fileio.cs

@@ -361,13 +361,13 @@ public override BigInteger readinto(CodeContext/*!*/ context, object buf) {
                 + "seeking beyond the end of a file).\n"
                 + "Note that not all file objects are seekable."
                 )]
-            public override BigInteger seek(CodeContext/*!*/ context, BigInteger offset, [DefaultParameterValue(0)]object whence) {
+            public override BigInteger seek(CodeContext/*!*/ context, BigInteger offset, [Optional]object whence) {
                 _checkClosed();
 
                 return _readStream.Seek((long)offset, (SeekOrigin)GetInt(whence));
             }
 
-            public BigInteger seek(double offset, [DefaultParameterValue(0)]object whence) {
+            public BigInteger seek(double offset, [Optional]object whence) {
                 _checkClosed();
 
                 throw PythonOps.TypeError("an integer is required");

Src/IronPython.Modules/_io.cs

@@ -1,21 +1,20 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information.
-using System.Linq.Expressions;
-
-using System.Numerics;
 
 using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Dynamic;
 using System.IO;
+using System.Linq.Expressions;
+using System.Numerics;
+using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
 
-using Microsoft.Scripting;
 using Microsoft.Scripting.Runtime;
 using Microsoft.Scripting.Utils;
 
@@ -241,7 +240,7 @@ public virtual List readlines([DefaultParameterValue(null)]object hint) {
                 return res;
             }
 
-            public virtual BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [DefaultParameterValue(0)]object whence) {
+            public virtual BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [Optional]object whence) {
                 throw UnsupportedOperation(context, "seek");
             }
 
@@ -911,13 +910,13 @@ public override BigInteger tell(CodeContext/*!*/ context) {
                 return res - _readBuf.Count + _readBufPos;
             }
 
-            public BigInteger seek(double offset, [DefaultParameterValue(0)]object whence) {
+            public BigInteger seek(double offset, [Optional]object whence) {
                 _checkClosed();
 
                 throw PythonOps.TypeError("an integer is required");
             }
 
-            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [DefaultParameterValue(0)]object whence) {
+            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [Optional]object whence) {
                 int whenceInt = GetInt(whence);
                 if (whenceInt < 0 || whenceInt > 2) {
                     throw PythonOps.ValueError("invalid whence ({0}, should be 0, 1, or 2)", whenceInt);
@@ -1251,13 +1250,13 @@ public override BigInteger tell(CodeContext/*!*/ context) {
                 return res + _writeBuf.Count;
             }
 
-            public BigInteger seek(double offset, [DefaultParameterValue(0)]object whence) {
+            public BigInteger seek(double offset, [Optional]object whence) {
                 _checkClosed();
 
                 throw PythonOps.TypeError("an integer is required");
             }
 
-            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [DefaultParameterValue(0)]object whence) {
+            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [Optional]object whence) {
                 int whenceInt = GetInt(whence);
                 if (whenceInt < 0 || whenceInt > 2) {
                     throw PythonOps.ValueError("invalid whence ({0}, should be 0, 1, or 2)", whenceInt);
@@ -1646,13 +1645,13 @@ public override BigInteger readinto(CodeContext/*!*/ context, object buf) {
                 return base.readinto(context, buf);
             }
 
-            public BigInteger seek(double offset, [DefaultParameterValue(0)]object whence) {
+            public BigInteger seek(double offset, [Optional]object whence) {
                 _checkClosed();
 
                 throw PythonOps.TypeError("an integer is required");
             }
 
-            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [DefaultParameterValue(0)]object whence) {
+            public override BigInteger seek(CodeContext/*!*/ context, BigInteger pos, [Optional]object whence) {
                 int whenceInt = GetInt(whence);
                 if (whenceInt < 0 || whenceInt > 2) {
                     throw PythonOps.ValueError("invalid whence ({0}, should be 0, 1, or 2)", whenceInt);
@@ -2289,13 +2288,13 @@ public override object detach(CodeContext/*!*/ context) {
                 return res;
             }
 
-            public BigInteger seek(double offset, [DefaultParameterValue(0)]object whence) {
+            public BigInteger seek(double offset, [Optional]object whence) {
                 _checkClosed();
 
                 throw PythonOps.TypeError("an integer is required");
             }
 
-            public override BigInteger seek(CodeContext/*!*/ context, BigInteger cookie, [DefaultParameterValue(0)]object whence) {
+            public override BigInteger seek(CodeContext/*!*/ context, BigInteger cookie, [Optional]object whence) {
                 int whenceInt = GetInt(whence);
                 if (closed) {
                     throw PythonOps.ValueError("tell on closed file");
@@ -3116,6 +3115,8 @@ private static int GetInt(object i, int defaultValue) {
         }
 
         private static int GetInt(object i, string msg, params object[] args) {
+            if (i == Missing.Value) return 0;
+
             int res;
             if (TryGetInt(i, out res)) {
                 return res;

Tests/test_regressions.py

@@ -1352,4 +1352,14 @@ class test(object):
 
         self.assertIs(test().defaultValue, noValue)
 
+    def test_ipy2_gh546(self):
+        """https://github.com/IronLanguages/ironpython2/issues/546"""
+        from io import StringIO
+        class Test(StringIO): pass
+        Test().seek(0)
+
+        from io import BytesIO
+        class Test(BytesIO): pass
+        Test().seek(0)
+
 run_test(__name__)