fix std.io.InStream for windows

now we handle PIPE_BROKEN as an EOF

also set up framework for debugging unexpected posix/windows errors

6 files changed, 95 insertions, 58 deletions

diff --git a/std/debug.zig b/std/debug.zig
index aef67c315f..24f4be9fe1 100644
--- a/std/debug.zig
+++ b/std/debug.zig
@@ -11,6 +11,7 @@ error MissingDebugInfo;
 error InvalidDebugInfo;
 error UnsupportedDebugInfo;
 
+
 pub fn assert(ok: bool) {
     if (!ok) {
         // In ReleaseFast test mode, we still want assert(false) to crash, so
diff --git a/std/io.zig b/std/io.zig
index 54cefb804c..124e7714da 100644
--- a/std/io.zig
+++ b/std/io.zig
@@ -45,17 +45,12 @@ pub var stderr = OutStream {
 /// bug in the program that called the function.
 error Invalid;
 
-/// When an Unexpected error occurs, code that emitted the error likely needs
-/// a patch to recognize the unexpected case so that it can handle it and emit
-/// a more specific error.
-error Unexpected;
-
 error DiskQuota;
 error FileTooBig;
 error Io;
 error NoSpaceLeft;
 error BadPerm;
-error PipeFail;
+error BrokenPipe;
 error BadFd;
 error IsDir;
 error NotDir;
@@ -207,7 +202,10 @@ pub const OutStream = struct {
         if (self.handle) |handle| return handle;
         if (system.GetStdHandle(self.handle_id)) |handle| {
             if (handle == system.INVALID_HANDLE_VALUE) {
-                return error.Unexpected;
+                const err = system.GetLastError();
+                return switch (err) {
+                    else => os.unexpectedErrorWindows(err),
+                };
             }
             self.handle = handle;
             return handle;
@@ -292,7 +290,7 @@ pub const InStream = struct {
                         system.EFAULT => unreachable,
                         system.EBADF  => return error.BadFd,
                         system.EIO    => return error.Io,
-                        else          => return error.Unexpected,
+                        else          => return os.unexpectedErrorPosix(read_err),
                     }
                 }
                 if (amt_read == 0) return index;
@@ -309,12 +307,12 @@ pub const InStream = struct {
                     const err = system.GetLastError();
                     return switch (err) {
                         system.ERROR.OPERATION_ABORTED => continue,
-                        system.ERROR.BROKEN_PIPE => error.PipeFail,
-                        else => error.Unexpected,
+                        system.ERROR.BROKEN_PIPE => return index,
+                        else => os.unexpectedErrorWindows(err),
                     };
                 }
+                if (amt_read == 0) return index;
                 index += amt_read;
-                if (amt_read < want_read_count) return index;
             }
             return index;
         } else {
@@ -374,7 +372,7 @@ pub const InStream = struct {
                         system.EOVERFLOW => error.Unseekable,
                         system.ESPIPE => error.Unseekable,
                         system.ENXIO => error.Unseekable,
-                        else => error.Unexpected,
+                        else => os.unexpectedErrorPosix(err),
                     };
                 }
             },
@@ -394,7 +392,7 @@ pub const InStream = struct {
                         system.EOVERFLOW => error.Unseekable,
                         system.ESPIPE => error.Unseekable,
                         system.ENXIO => error.Unseekable,
-                        else => error.Unexpected,
+                        else => os.unexpectedErrorPosix(err),
                     };
                 }
             },
@@ -414,7 +412,7 @@ pub const InStream = struct {
                         system.EOVERFLOW => error.Unseekable,
                         system.ESPIPE => error.Unseekable,
                         system.ENXIO => error.Unseekable,
-                        else => error.Unexpected,
+                        else => os.unexpectedErrorPosix(err),
                     };
                 }
                 return result;
@@ -430,7 +428,7 @@ pub const InStream = struct {
             return switch (err) {
                 system.EBADF => error.BadFd,
                 system.ENOMEM => error.OutOfMemory,
-                else => error.Unexpected,
+                else => os.unexpectedErrorPosix(err),
             }
         }
 
@@ -485,7 +483,10 @@ pub const InStream = struct {
         if (self.handle) |handle| return handle;
         if (system.GetStdHandle(self.handle_id)) |handle| {
             if (handle == system.INVALID_HANDLE_VALUE) {
-                return error.Unexpected;
+                const err = system.GetLastError();
+                return switch (err) {
+                    else => os.unexpectedErrorWindows(err),
+                };
             }
             self.handle = handle;
             return handle;
diff --git a/std/net.zig b/std/net.zig
index 1a0bfb6f03..3551499c6b 100644
--- a/std/net.zig
+++ b/std/net.zig
@@ -3,7 +3,6 @@ const assert = @import("debug.zig").assert;
 const endian = @import("endian.zig");
 
 error SigInterrupt;
-error Unexpected;
 error Io;
 error TimedOut;
 error ConnectionReset;
diff --git a/std/os/index.zig b/std/os/index.zig
index 5eb3c1b8ef..498c10f518 100644
--- a/std/os/index.zig
+++ b/std/os/index.zig
@@ -51,7 +51,6 @@ const ArrayList = @import("../array_list.zig").ArrayList;
 const Buffer = @import("../buffer.zig").Buffer;
 const math = @import("../index.zig").math;
 
-error Unexpected;
 error SystemResources;
 error AccessDenied;
 error InvalidExe;
@@ -81,7 +80,7 @@ pub fn getRandomBytes(buf: []u8) -> %void {
                     posix.EINVAL => unreachable,
                     posix.EFAULT => unreachable,
                     posix.EINTR  => continue,
-                    else         => error.Unexpected,
+                    else         => unexpectedErrorPosix(err),
                 }
             }
             return;
@@ -96,12 +95,18 @@ pub fn getRandomBytes(buf: []u8) -> %void {
         Os.windows => {
             var hCryptProv: windows.HCRYPTPROV = undefined;
             if (windows.CryptAcquireContextA(&hCryptProv, null, null, windows.PROV_RSA_FULL, 0) == 0) {
-                return error.Unexpected;
+                const err = windows.GetLastError();
+                return switch (err) {
+                    else => unexpectedErrorWindows(err),
+                };
             }
             defer _ = windows.CryptReleaseContext(hCryptProv, 0);
 
             if (windows.CryptGenRandom(hCryptProv, windows.DWORD(buf.len), buf.ptr) == 0) {
-                return error.Unexpected;
+                const err = windows.GetLastError();
+                return switch (err) {
+                    else => unexpectedErrorWindows(err),
+                };
             }
         },
         else => @compileError("Unsupported OS"),
@@ -187,8 +192,8 @@ pub fn posixRead(fd: i32, buf: []u8) -> %void {
                 posix.EIO => error.InputOutput,
                 posix.EISDIR => error.IsDir,
                 posix.ENOBUFS, posix.ENOMEM => error.SystemResources,
-                else => return error.Unexpected,
-            }
+                else => unexpectedErrorPosix(err),
+            };
         }
         index += amt_written;
     }
@@ -202,7 +207,6 @@ error FileTooBig;
 error InputOutput;
 error NoSpaceLeft;
 error BrokenPipe;
-error Unexpected;
 
 /// Calls POSIX write, and keeps trying if it gets interrupted.
 pub fn posixWrite(fd: i32, bytes: []const u8) -> %void {
@@ -222,8 +226,8 @@ pub fn posixWrite(fd: i32, bytes: []const u8) -> %void {
                 posix.ENOSPC => error.NoSpaceLeft,
                 posix.EPERM  => error.AccessDenied,
                 posix.EPIPE  => error.BrokenPipe,
-                else         => error.Unexpected,
-            }
+                else         => unexpectedErrorPosix(write_err),
+            };
         }
         return;
     }
@@ -277,7 +281,7 @@ pub fn posixOpen(file_path: []const u8, flags: u32, perm: usize, allocator: ?&Al
                 posix.ENOTDIR => error.NotDir,
                 posix.EPERM => error.AccessDenied,
                 posix.EEXIST => error.PathAlreadyExists,
-                else => error.Unexpected,
+                else => unexpectedErrorPosix(err),
             }
         }
         return i32(result);
@@ -292,7 +296,7 @@ pub fn posixDup2(old_fd: i32, new_fd: i32) -> %void {
                 posix.EBUSY, posix.EINTR => continue,
                 posix.EMFILE => error.ProcessFdQuotaExceeded,
                 posix.EINVAL => unreachable,
-                else => error.Unexpected,
+                else => unexpectedErrorPosix(err),
             };
         }
         return;
@@ -404,7 +408,7 @@ fn posixExecveErrnoToErr(err: usize) -> error {
         posix.ENOENT => error.FileNotFound,
         posix.ENOTDIR => error.NotDir,
         posix.ETXTBSY => error.FileBusy,
-        else => error.Unexpected,
+        else => unexpectedErrorPosix(err),
     };
 }
 
@@ -491,7 +495,7 @@ pub fn getEnvVarOwned(allocator: &mem.Allocator, key: []const u8) -> %[]u8 {
                 const err = windows.GetLastError();
                 return switch (err) {
                     windows.ERROR.ENVVAR_NOT_FOUND => error.EnvironmentVariableNotFound,
-                    else => error.Unexpected,
+                    else => unexpectedErrorWindows(err),
                 };
             }
 
@@ -519,7 +523,10 @@ pub fn getCwd(allocator: &Allocator) -> %[]u8 {
                 const result = windows.GetCurrentDirectoryA(windows.WORD(buf.len), buf.ptr);
 
                 if (result == 0) {
-                    return error.Unexpected;
+                    const err = windows.GetLastError();
+                    return switch (err) {
+                        else => unexpectedErrorWindows(err),
+                    };
                 }
 
                 if (result > buf.len) {
@@ -539,7 +546,7 @@ pub fn getCwd(allocator: &Allocator) -> %[]u8 {
                     buf = %return allocator.realloc(u8, buf, buf.len * 2);
                     continue;
                 } else if (err > 0) {
-                    return error.Unexpected;
+                    return unexpectedErrorPosix(err);
                 }
 
                 return allocator.shrink(u8, buf, cstr.len(buf.ptr));
@@ -570,7 +577,7 @@ pub fn symLinkWindows(allocator: &Allocator, existing_path: []const u8, new_path
     if (windows.CreateSymbolicLinkA(existing_with_null.ptr, new_with_null.ptr, 0) == 0) {
         const err = windows.GetLastError();
         return switch (err) {
-            else => error.Unexpected,
+            else => unexpectedErrorWindows(err),
         };
     }
 }
@@ -602,7 +609,7 @@ pub fn symLinkPosix(allocator: &Allocator, existing_path: []const u8, new_path:
             posix.ENOMEM => error.SystemResources,
             posix.ENOSPC => error.NoSpaceLeft,
             posix.EROFS => error.ReadOnlyFileSystem,
-            else => error.Unexpected,
+            else => unexpectedErrorPosix(err),
         };
     }
 }
@@ -663,7 +670,7 @@ pub fn deleteFileWindows(allocator: &Allocator, file_path: []const u8) -> %void
             windows.ERROR.FILE_NOT_FOUND => error.FileNotFound,
             windows.ERROR.ACCESS_DENIED => error.AccessDenied,
             windows.ERROR.FILENAME_EXCED_RANGE, windows.ERROR.INVALID_PARAMETER => error.NameTooLong,
-            else => error.Unexpected,
+            else => unexpectedErrorWindows(err),
         }
     }
 }
@@ -689,7 +696,7 @@ pub fn deleteFilePosix(allocator: &Allocator, file_path: []const u8) -> %void {
             posix.ENOTDIR => error.NotDir,
             posix.ENOMEM => error.SystemResources,
             posix.EROFS => error.ReadOnlyFileSystem,
-            else => error.Unexpected,
+            else => unexpectedErrorPosix(err),
         };
     }
 }
@@ -743,7 +750,7 @@ pub fn rename(allocator: &Allocator, old_path: []const u8, new_path: []const u8)
         if (windows.MoveFileExA(old_buf.ptr, new_buf.ptr, flags) == 0) {
             const err = windows.GetLastError();
             return switch (err) {
-                else => return error.Unexpected,
+                else => unexpectedErrorWindows(err),
             };
         }
     } else {
@@ -765,7 +772,7 @@ pub fn rename(allocator: &Allocator, old_path: []const u8, new_path: []const u8)
                 posix.EEXIST, posix.ENOTEMPTY => error.PathAlreadyExists,
                 posix.EROFS => error.ReadOnlyFileSystem,
                 posix.EXDEV => error.RenameAcrossMountPoints,
-                else => error.Unexpected,
+                else => unexpectedErrorPosix(err),
             };
         }
     }
@@ -788,7 +795,7 @@ pub fn makeDirWindows(allocator: &Allocator, dir_path: []const u8) -> %void {
         return switch (err) {
             windows.ERROR.ALREADY_EXISTS => error.PathAlreadyExists,
             windows.ERROR.PATH_NOT_FOUND => error.FileNotFound,
-            else => error.Unexpected,
+            else => unexpectedErrorWindows(err),
         };
     }
 }
@@ -812,7 +819,7 @@ pub fn makeDirPosix(allocator: &Allocator, dir_path: []const u8) -> %void {
             posix.ENOSPC => error.NoSpaceLeft,
             posix.ENOTDIR => error.NotDir,
             posix.EROFS => error.ReadOnlyFileSystem,
-            else => error.Unexpected,
+            else => unexpectedErrorPosix(err),
         };
     }
 }
@@ -877,7 +884,7 @@ pub fn deleteDir(allocator: &Allocator, dir_path: []const u8) -> %void {
             posix.ENOTDIR => error.NotDir,
             posix.EEXIST, posix.ENOTEMPTY => error.DirNotEmpty,
             posix.EROFS => error.ReadOnlyFileSystem,
-            else => error.Unexpected,
+            else => unexpectedErrorPosix(err),
         };
     }
 }
@@ -988,7 +995,7 @@ pub const Dir = struct {
                             self.buf = %return self.allocator.realloc(u8, self.buf, self.buf.len * 2);
                             continue;
                         },
-                        else => return error.Unexpected,
+                        else => return unexpectedErrorPosix(err),
                     };
                 }
                 if (result == 0)
@@ -1045,7 +1052,7 @@ pub fn changeCurDir(allocator: &Allocator, dir_path: []const u8) -> %void {
             posix.ENOENT => error.FileNotFound,
             posix.ENOMEM => error.SystemResources,
             posix.ENOTDIR => error.NotDir,
-            else => error.Unexpected,
+            else => unexpectedErrorPosix(err),
         };
     }
 }
@@ -1073,7 +1080,7 @@ pub fn readLink(allocator: &Allocator, pathname: []const u8) -> %[]u8 {
                 posix.ENOENT => error.FileNotFound,
                 posix.ENOMEM => error.SystemResources,
                 posix.ENOTDIR => error.NotDir,
-                else => error.Unexpected,
+                else => unexpectedErrorPosix(err),
             };
         }
         if (ret_val == result_buf.len) {
@@ -1132,7 +1139,6 @@ test "os.sleep" {
 error ResourceLimitReached;
 error InvalidUserId;
 error PermissionDenied;
-error Unexpected;
 
 pub fn posix_setuid(uid: u32) -> %void {
     const err = posix.getErrno(posix.setuid(uid));
@@ -1141,7 +1147,7 @@ pub fn posix_setuid(uid: u32) -> %void {
         posix.EAGAIN => error.ResourceLimitReached,
         posix.EINVAL => error.InvalidUserId,
         posix.EPERM => error.PermissionDenied,
-        else => error.Unexpected,
+        else => unexpectedErrorPosix(err),
     };
 }
 
@@ -1152,7 +1158,7 @@ pub fn posix_setreuid(ruid: u32, euid: u32) -> %void {
         posix.EAGAIN => error.ResourceLimitReached,
         posix.EINVAL => error.InvalidUserId,
         posix.EPERM => error.PermissionDenied,
-        else => error.Unexpected,
+        else => unexpectedErrorPosix(err),
     };
 }
 
@@ -1163,7 +1169,7 @@ pub fn posix_setgid(gid: u32) -> %void {
         posix.EAGAIN => error.ResourceLimitReached,
         posix.EINVAL => error.InvalidUserId,
         posix.EPERM => error.PermissionDenied,
-        else => error.Unexpected,
+        else => unexpectedErrorPosix(err),
     };
 }
 
@@ -1174,7 +1180,7 @@ pub fn posix_setregid(rgid: u32, egid: u32) -> %void {
         posix.EAGAIN => error.ResourceLimitReached,
         posix.EINVAL => error.InvalidUserId,
         posix.EPERM => error.PermissionDenied,
-        else => error.Unexpected,
+        else => unexpectedErrorPosix(err),
     };
 }
 
@@ -1417,3 +1423,29 @@ test "std.os" {
     _ = @import("path.zig");
     _ = @import("windows/index.zig");
 }
+
+
+error Unexpected;
+
+// TODO make this a build variable that you can set
+const unexpected_error_tracing = false;
+
+/// Call this when you made a syscall or something that sets errno
+/// and you get an unexpected error.
+pub fn unexpectedErrorPosix(errno: c_int) -> error {
+    if (unexpected_error_tracing) {
+        io.stderr.printf("unexpected errno: {}\n", errno) %% return;
+        debug.printStackTrace() %% return;
+    }
+    return error.Unexpected;
+}
+
+/// Call this when you made a windows DLL call or something that does SetLastError
+/// and you get an unexpected error.
+pub fn unexpectedErrorWindows(err: windows.DWORD) -> error {
+    if (unexpected_error_tracing) {
+        io.stderr.printf("unexpected GetLastError(): {}\n", err) %% return;
+        debug.printStackTrace() %% return;
+    }
+    return error.Unexpected;
+}
diff --git a/std/os/path.zig b/std/os/path.zig
index 93b7bc017c..beaabc38d6 100644
--- a/std/os/path.zig
+++ b/std/os/path.zig
@@ -915,7 +915,6 @@ error NotDir;
 error NameTooLong;
 error SymLinkLoop;
 error InputOutput;
-error Unexpected;
 /// Return the canonicalized absolute pathname.
 /// Expands all symbolic links and resolves references to `.`, `..`, and
 /// extra `/` characters in ::pathname.
@@ -938,7 +937,7 @@ pub fn real(allocator: &Allocator, pathname: []const u8) -> %[]u8 {
                     windows.ERROR.FILE_NOT_FOUND => error.FileNotFound,
                     windows.ERROR.ACCESS_DENIED => error.AccessDenied,
                     windows.ERROR.FILENAME_EXCED_RANGE => error.NameTooLong,
-                    else => error.Unexpected,
+                    else => os.unexpectedErrorWindows(err),
                 };
             }
             defer os.windowsClose(h_file);
@@ -954,7 +953,7 @@ pub fn real(allocator: &Allocator, pathname: []const u8) -> %[]u8 {
                         windows.ERROR.PATH_NOT_FOUND => error.FileNotFound,
                         windows.ERROR.NOT_ENOUGH_MEMORY => error.OutOfMemory,
                         windows.ERROR.INVALID_PARAMETER => unreachable,
-                        else => error.Unexpected,
+                        else => os.unexpectedErrorWindows(err),
                     };
                 }
 
@@ -1003,7 +1002,7 @@ pub fn real(allocator: &Allocator, pathname: []const u8) -> %[]u8 {
                     posix.ENAMETOOLONG => error.NameTooLong,
                     posix.ELOOP => error.SymLinkLoop,
                     posix.EIO => error.InputOutput,
-                    else => error.Unexpected,
+                    else => os.unexpectedErrorPosix(err),
                 };
             }
             return allocator.shrink(u8, result_buf, cstr.len(result_buf.ptr));
diff --git a/std/os/windows/util.zig b/std/os/windows/util.zig
index 84eceb81af..de2babe8d7 100644
--- a/std/os/windows/util.zig
+++ b/std/os/windows/util.zig
@@ -7,6 +7,7 @@ const BufMap = std.BufMap;
 
 error WaitAbandoned;
 error WaitTimeOut;
+error Unexpected;
 
 pub fn windowsWaitSingle(handle: windows.HANDLE, milliseconds: windows.DWORD) -> %void {
     const result = windows.WaitForSingleObject(handle, milliseconds);
@@ -14,8 +15,11 @@ pub fn windowsWaitSingle(handle: windows.HANDLE, milliseconds: windows.DWORD) ->
         windows.WAIT_ABANDONED => error.WaitAbandoned,
         windows.WAIT_OBJECT_0 => {},
         windows.WAIT_TIMEOUT => error.WaitTimeOut,
-        windows.WAIT_FAILED => switch (windows.GetLastError()) {
-            else => error.Unexpected,
+        windows.WAIT_FAILED => {
+            const err = windows.GetLastError();
+            switch (err) {
+                else => os.unexpectedErrorWindows(err),
+            }
         },
         else => error.Unexpected,
     };
@@ -32,14 +36,15 @@ error BrokenPipe;
 
 pub fn windowsWrite(handle: windows.HANDLE, bytes: []const u8) -> %void {
     if (windows.WriteFile(handle, @ptrCast(&const c_void, bytes.ptr), u32(bytes.len), null, null) == 0) {
-        return switch (windows.GetLastError()) {
+        const err = windows.GetLastError();
+        return switch (err) {
             windows.ERROR.INVALID_USER_BUFFER => error.SystemResources,
             windows.ERROR.NOT_ENOUGH_MEMORY => error.SystemResources,
             windows.ERROR.OPERATION_ABORTED => error.OperationAborted,
             windows.ERROR.NOT_ENOUGH_QUOTA => error.SystemResources,
             windows.ERROR.IO_PENDING => error.IoPending,
             windows.ERROR.BROKEN_PIPE => error.BrokenPipe,
-            else => error.Unexpected,
+            else => os.unexpectedErrorWindows(err),
         };
     }
 }
@@ -106,7 +111,7 @@ pub fn windowsOpen(file_path: []const u8, desired_access: windows.DWORD, share_m
             windows.ERROR.FILE_NOT_FOUND => error.FileNotFound,
             windows.ERROR.ACCESS_DENIED => error.AccessDenied,
             windows.ERROR.PIPE_BUSY => error.PipeBusy,
-            else => error.Unexpected,
+            else => os.unexpectedErrorWindows(err),
         };
     }