[WIP] fix #13790

compiler/lexer.nim

@@ -863,7 +863,7 @@ proc getSymbol(L: var Lexer, tok: var Token) =
     else: break
   tokenEnd(tok, pos-1)
   h = !$h
-  tok.ident = L.cache.getIdent(addr(L.buf[L.bufpos]), pos - L.bufpos, h)
+  tok.ident = L.cache.getIdent(L.buf[L.bufpos].addr.toCstring, pos - L.bufpos, h)
   if (tok.ident.id < ord(tokKeywordLow) - ord(tkSymbol)) or
       (tok.ident.id > ord(tokKeywordHigh) - ord(tkSymbol)):
     tok.tokType = tkSymbol
@@ -877,7 +877,7 @@ proc getSymbol(L: var Lexer, tok: var Token) =
 proc endOperator(L: var Lexer, tok: var Token, pos: int,
                  hash: Hash) {.inline.} =
   var h = !$hash
-  tok.ident = L.cache.getIdent(addr(L.buf[L.bufpos]), pos - L.bufpos, h)
+  tok.ident = L.cache.getIdent(L.buf[L.bufpos].addr.toCstring, pos - L.bufpos, h)
   if (tok.ident.id < oprLow) or (tok.ident.id > oprHigh): tok.tokType = tkOpr
   else: tok.tokType = TokType(tok.ident.id - oprLow + ord(tkColon))
   L.bufpos = pos

compiler/options.nim

@@ -172,7 +172,10 @@ type
     ideNone, ideSug, ideCon, ideDef, ideUse, ideDus, ideChk, ideMod,
     ideHighlight, ideOutline, ideKnown, ideMsg, ideProject
 
-  Feature* = enum  ## experimental features; DO NOT RENAME THESE!
+  Feature* = enum
+    ## experimental featuress
+    ## do not rename these since they're exposed to users via `--experimental:foo`
+    ## deprecated features start with `legacy`.
     implicitDeref,
     dotOperators,
     callOperator,
@@ -190,7 +193,8 @@ type
     vmopsDanger,
     strictFuncs,
     views,
-    strictNotNil
+    strictNotNil,
+    legacyImplicitCstringConv,
 
   LegacyFeature* = enum
     allowSemcheckedAstModification,
@@ -369,6 +373,14 @@ template setErrorMaxHighMaybe*(conf: ConfigRef) =
   ## do not stop after first error (but honor --errorMax if provided)
   assignIfDefault(conf.errorMax, high(int))
 
+template toSet(a: typedesc[enum]): untyped = {a.low..a.high}
+
+const
+  FeatureDepr* = {legacyImplicitCstringConv}
+    # can't use `LegacyFeature` because we want to be able to localize
+    # to a context, eg {.push experimental: "legacyImplicitCstringConv".} .. {.pop.}
+  FeatureExp* = Feature.toSet - FeatureDepr
+
 proc setNoteDefaults*(conf: ConfigRef, note: TNoteKind, enabled = true) =
   template fun(op) =
     conf.notes.op note

compiler/sighashes.nim

@@ -14,7 +14,7 @@ from hashes import Hash
 import types
 
 proc `&=`(c: var MD5Context, s: string) = md5Update(c, s, s.len)
-proc `&=`(c: var MD5Context, ch: char) = md5Update(c, unsafeAddr ch, 1)
+proc `&=`(c: var MD5Context, ch: char) = md5Update(c, unsafeAddr(ch).toCstring, 1)
 proc `&=`(c: var MD5Context, r: Rope) =
   for l in leaves(r): md5Update(c, l, l.len)
 proc `&=`(c: var MD5Context, i: BiggestInt) =

compiler/sigmatch.nim

@@ -1405,16 +1405,24 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
     of tyNil: result = f.allowsNil
     of tyString: result = isConvertible
     of tyPtr:
-      # ptr[Tag, char] is not convertible to 'cstring' for now:
-      if a.len == 1:
-        let pointsTo = a[0].skipTypes(abstractInst)
-        if pointsTo.kind == tyChar: result = isConvertible
-        elif pointsTo.kind == tyUncheckedArray and pointsTo[0].kind == tyChar:
-          result = isConvertible
-        elif pointsTo.kind == tyArray and firstOrd(nil, pointsTo[0]) == 0 and
-            skipTypes(pointsTo[0], {tyRange}).kind in {tyInt..tyInt64} and
-            pointsTo[1].kind == tyChar:
-          result = isConvertible
+      if legacyImplicitCstringConv in c.c.features:
+        # issue #13790
+        # ptr[Tag, char] is not convertible to 'cstring' for now:
+        # xxx: aren't memory regions not used anymore?
+        if a.len == 1:
+          let pointsTo = a[0].skipTypes(abstractInst)
+          if pointsTo.kind == tyChar: result = isConvertible
+          elif pointsTo.kind == tyUncheckedArray and pointsTo[0].kind == tyChar:
+            result = isConvertible
+          elif pointsTo.kind == tyArray and firstOrd(nil, pointsTo[0]) == 0 and
+              skipTypes(pointsTo[0], {tyRange}).kind in {tyInt..tyInt64} and
+              pointsTo[1].kind == tyChar:
+            result = isConvertible
+          # if result == isConvertible:
+            # message(c.config, a.info, warnOldImplicitCstringConv)
+            # warnProveInit
+      else:
+        result = isNone
     else: discard
 
   of tyEmpty, tyVoid:

lib/impure/db_odbc.nim

@@ -91,8 +91,8 @@
 import strutils, odbcsql
 import db_common
 export db_common
-
 import std/private/since
+from system/dollars import toString0
 
 type
   OdbcConnTyp = tuple[hDb: SqlHDBC, env: SqlHEnv, stmt: SqlHStmt]
@@ -133,7 +133,7 @@ proc getErrInfo(db: var DbConn): tuple[res: int, ss, ne, msg: string] {.
               511.TSqlSmallInt, retSz.addr)
   except:
     discard
-  return (res.int, $(addr sqlState), $(addr nativeErr), $(addr errMsg))
+  return (res.int, sqlState.toString0, nativeErr.toString0, errMsg.toString0)
 
 proc dbError*(db: var DbConn) {.
           tags: [ReadDbEffect, WriteDbEffect], raises: [DbError] .} =
@@ -183,7 +183,7 @@ proc sqlGetDBMS(db: var DbConn): string {.
     db.sqlCheck(SQLGetInfo(db.hDb, SQL_DBMS_NAME, cast[SqlPointer](buf.addr),
                         4095.TSqlSmallInt, sz.addr))
   except: discard
-  return $(addr buf)
+  result = toString0(buf)
 
 proc dbQuote*(s: string): string {.noSideEffect.} =
   ## DB quotes the string.
@@ -294,7 +294,7 @@ iterator fastRows*(db: var DbConn, query: SqlQuery,
         buf[0] = '\0'
         db.sqlCheck(SQLGetData(db.stmt, colId.SqlUSmallInt, SQL_C_CHAR,
                                  cast[cstring](buf.addr), 4095, sz.addr))
-        rowRes[colId-1] = $(addr buf)
+        rowRes[colId-1] = toString0(buf)
       yield rowRes
       res = SQLFetch(db.stmt)
   properFreeResult(SQL_HANDLE_STMT, db.stmt)
@@ -322,7 +322,7 @@ iterator instantRows*(db: var DbConn, query: SqlQuery,
         buf[0] = '\0'
         db.sqlCheck(SQLGetData(db.stmt, colId.SqlUSmallInt, SQL_C_CHAR,
                                  cast[cstring](buf.addr), 4095, sz.addr))
-        rowRes[colId-1] = $(addr buf)
+        rowRes[colId-1] = toString0(buf)
       yield (row: rowRes, len: cCnt.int)
       res = SQLFetch(db.stmt)
   properFreeResult(SQL_HANDLE_STMT, db.stmt)
@@ -361,7 +361,7 @@ proc getRow*(db: var DbConn, query: SqlQuery,
       buf[0] = '\0'
       db.sqlCheck(SQLGetData(db.stmt, colId.SqlUSmallInt, SQL_C_CHAR,
                                cast[cstring](buf.addr), 4095, sz.addr))
-      rowRes[colId-1] = $(addr buf)
+      rowRes[colId-1] = toString0(buf)
     res = SQLFetch(db.stmt)
     result = rowRes
   properFreeResult(SQL_HANDLE_STMT, db.stmt)
@@ -389,7 +389,7 @@ proc getAllRows*(db: var DbConn, query: SqlQuery,
         buf[0] = '\0'
         db.sqlCheck(SQLGetData(db.stmt, colId.SqlUSmallInt, SQL_C_CHAR,
                                  cast[cstring](buf.addr), 4095, sz.addr))
-        rowRes[colId-1] = $(addr buf)
+        rowRes[colId-1] = toString0(buf)
       rows.add(rowRes)
       res = SQLFetch(db.stmt)
     result = rows

lib/posix/posix_utils.nim

@@ -13,13 +13,11 @@
 
 import posix, parsecfg, os
 import std/private/since
+from system/dollars import toString0
 
 type Uname* = object
   sysname*, nodename*, release*, version*, machine*: string
 
-template charArrayToString(input: typed): string =
-  $cstring(addr input)
-
 proc uname*(): Uname =
   ## Provides system information in a `Uname` struct with sysname, nodename,
   ## release, version and machine attributes.
@@ -33,11 +31,11 @@ proc uname*(): Uname =
   if uname(u) != 0:
     raise newException(OSError, $strerror(errno))
 
-  result.sysname = charArrayToString u.sysname
-  result.nodename = charArrayToString u.nodename
-  result.release = charArrayToString u.release
-  result.version = charArrayToString u.version
-  result.machine = charArrayToString u.machine
+  result.sysname = toString0 u.sysname
+  result.nodename = toString0 u.nodename
+  result.release = toString0 u.release
+  result.version = toString0 u.version
+  result.machine = toString0 u.machine
 
 proc fsync*(fd: int) =
  ## synchronize a file's buffer cache to the storage device

lib/pure/asyncnet.nim

@@ -224,7 +224,7 @@ when defineSsl:
     let len = bioCtrlPending(socket.bioOut)
     if len > 0:
       var data = newString(len)
-      let read = bioRead(socket.bioOut, addr data[0], len)
+      let read = bioRead(socket.bioOut, data.toCstring, len)
       assert read != 0
       if read < 0:
         raiseSSLError()
@@ -242,7 +242,7 @@ when defineSsl:
       var data = await recv(socket.fd.AsyncFD, BufferSize, flags)
       let length = len(data)
       if length > 0:
-        let ret = bioWrite(socket.bioIn, addr data[0], length.cint)
+        let ret = bioWrite(socket.bioIn, data.toCstring, length.cint)
         if ret < 0:
           raiseSSLError()
       elif length == 0:
@@ -453,7 +453,7 @@ proc send*(socket: AsyncSocket, data: string,
     when defineSsl:
       var copy = data
       sslLoop(socket, flags,
-        sslWrite(socket.sslHandle, addr copy[0], copy.len.cint))
+        sslWrite(socket.sslHandle, copy.toCstring, copy.len.cint))
       await sendPendingSslData(socket, flags)
   else:
     await send(socket.fd.AsyncFD, data, flags)

lib/pure/nativesockets.nim

@@ -473,13 +473,13 @@ proc getAddrString*(sockAddr: ptr SockAddr): string =
     result = newString(addrLen)
     let addr6 = addr cast[ptr Sockaddr_in6](sockAddr).sin6_addr
     when not useWinVersion:
-      if posix.inet_ntop(posix.AF_INET6, addr6, addr result[0],
+      if posix.inet_ntop(posix.AF_INET6, addr6, result.toCstring,
                          result.len.int32) == nil:
         raiseOSError(osLastError())
       if posix.IN6_IS_ADDR_V4MAPPED(addr6) != 0:
         result = result.substr("::ffff:".len)
     else:
-      if winlean.inet_ntop(winlean.AF_INET6, addr6, addr result[0],
+      if winlean.inet_ntop(winlean.AF_INET6, addr6, result.toCstring,
                            result.len.int32) == nil:
         raiseOSError(osLastError())
     setLen(result, len(cstring(result)))
@@ -500,23 +500,23 @@ proc getAddrString*(sockAddr: ptr SockAddr, strAddress: var string) =
   if sockAddr.sa_family.cint == nativeAfInet:
     let addr4 = addr cast[ptr Sockaddr_in](sockAddr).sin_addr
     when not useWinVersion:
-      if posix.inet_ntop(posix.AF_INET, addr4, addr strAddress[0],
+      if posix.inet_ntop(posix.AF_INET, addr4, strAddress.cstring,
                          strAddress.len.int32) == nil:
         raiseOSError(osLastError())
     else:
-      if winlean.inet_ntop(winlean.AF_INET, addr4, addr strAddress[0],
+      if winlean.inet_ntop(winlean.AF_INET, addr4, strAddress.cstring,
                            strAddress.len.int32) == nil:
         raiseOSError(osLastError())
   elif sockAddr.sa_family.cint == nativeAfInet6:
     let addr6 = addr cast[ptr Sockaddr_in6](sockAddr).sin6_addr
     when not useWinVersion:
-      if posix.inet_ntop(posix.AF_INET6, addr6, addr strAddress[0],
+      if posix.inet_ntop(posix.AF_INET6, addr6, strAddress.cstring,
                          strAddress.len.int32) == nil:
         raiseOSError(osLastError())
       if posix.IN6_IS_ADDR_V4MAPPED(addr6) != 0:
         strAddress = strAddress.substr("::ffff:".len)
     else:
-      if winlean.inet_ntop(winlean.AF_INET6, addr6, addr strAddress[0],
+      if winlean.inet_ntop(winlean.AF_INET6, addr6, strAddress.cstring,
                            strAddress.len.int32) == nil:
         raiseOSError(osLastError())
   else:
@@ -575,7 +575,7 @@ proc getLocalAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
     # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
     result[0] = newString(64)
     if inet_ntop(name.sin6_family.cint,
-        addr name.sin6_addr, addr result[0][0], (result[0].len+1).int32).isNil:
+        addr name.sin6_addr, result[0].toCstring, (result[0].len+1).int32).isNil:
       raiseOSError(osLastError())
     setLen(result[0], result[0].cstring.len)
     result[1] = Port(nativesockets.ntohs(name.sin6_port))
@@ -612,7 +612,7 @@ proc getPeerAddr*(socket: SocketHandle, domain: Domain): (string, Port) =
     # Cannot use INET6_ADDRSTRLEN here, because it's a C define.
     result[0] = newString(64)
     if inet_ntop(name.sin6_family.cint,
-        addr name.sin6_addr, addr result[0][0], (result[0].len+1).int32).isNil:
+        addr name.sin6_addr, result[0].toCstring, (result[0].len+1).int32).isNil:
       raiseOSError(osLastError())
     setLen(result[0], result[0].cstring.len)
     result[1] = Port(nativesockets.ntohs(name.sin6_port))

lib/pure/os.nim

@@ -2314,11 +2314,14 @@ iterator walkDir*(dir: string; relative = false, checkDir = false):
         if checkDir:
           raiseOSError(osLastError(), dir)
       else:
+        # var y: string
         defer: discard closedir(d)
         while true:
           var x = readdir(d)
           if x == nil: break
-          var y = $cstring(addr x.d_name)
+          # y.setLen 0
+          # y.strAppend x.d_name.toCstring
+          var y = $x.d_name.toCstring
           if y != "." and y != "..":
             var s: Stat
             let path = dir / y

lib/pure/strutils.nim

@@ -1906,7 +1906,7 @@ func find*(s, sub: string, start: Natural = 0, last = 0): int {.rtl,
     else:
       when hasCStringBuiltin:
         if last == 0 and s.len > start:
-          let found = c_strstr(s[start].unsafeAddr, sub)
+          let found = c_strstr(s[start].unsafeAddr.toCstring, sub)
           if not found.isNil:
             result = cast[ByteAddress](found) -% cast[ByteAddress](s.cstring)
           else:
@@ -2372,11 +2372,11 @@ func formatBiggestFloat*(f: BiggestFloat, format: FloatFormatMode = ffDefault,
       frmtstr[3] = '*'
       frmtstr[4] = floatFormatToChar[format]
       frmtstr[5] = '\0'
-      L = c_sprintf(addr buf, addr frmtstr, precision, f)
+      L = c_sprintf(buf.toCstring, frmtstr.toCstring, precision, f)
     else:
       frmtstr[1] = floatFormatToChar[format]
       frmtstr[2] = '\0'
-      L = c_sprintf(addr buf, addr frmtstr, f)
+      L = c_sprintf(buf.toCstring, frmtstr.toCstring, f)
     result = newString(L)
     for i in 0 ..< L:
       # Depending on the locale either dot or comma is produced,

lib/system.nim

@@ -307,6 +307,16 @@ type
   UncheckedArray*[T]{.magic: "UncheckedArray".}
   ## Array with no bounds checking.
 
+template toCstring*(a: ptr char): cstring = cast[cstring](a)
+  ## `toCstring` is more typesafe than `cast`
+template toCstring*[N](a: ptr array[N, char]): cstring = cast[cstring](a)
+template toCstring*[N](a: array[N, char]): cstring = cast[cstring](a.addr)
+template toCstring*(a: ptr UncheckedArray[char]): cstring = cast[cstring](a)
+template toCstring*(a: UncheckedArray[char]): cstring = cast[cstring](a.addr)
+template toCstring*(a: string): cstring = a.cstring
+  # we already have implicit conversion for string=>cstring but seems cleaner
+  # to require explicit conversion here too
+
 type sink*[T]{.magic: "BuiltinType".}
 type lent*[T]{.magic: "BuiltinType".}
 
@@ -1017,9 +1027,12 @@ proc setLen*[T](s: var seq[T], newlen: Natural) {.
   ##   x.setLen(1)
   ##   assert x == @[10]
 
-proc setLen*(s: var string, newlen: Natural) {.
+proc setLen*(s: var string, newlen: Natural, isInit = true) {.
   magic: "SetLengthStr", noSideEffect.}
-  ## Sets the length of string `s` to `newlen`.
+  ## Sets the length of string `s` to `newlen`. If `isInit == true` and
+  ## If `newlen > s.len`, when `isInit == true`, new entries are '\0' including
+  ## the unreachable terminator n[s.len]. when `isInit == false`, only the
+  ## terminator is '\0' (for optimization). TODO: implement this.
   ##
   ## If the current length is greater than the new length,
   ## `s` will be truncated.
@@ -2078,7 +2091,7 @@ template newException*(exceptn: typedesc, message: string;
 when hostOS == "standalone" and defined(nogc):
   proc nimToCStringConv(s: NimString): cstring {.compilerproc, inline.} =
     if s == nil or s.len == 0: result = cstring""
-    else: result = cstring(addr s.data)
+    else: result = s.data.toCstring
 
 proc getTypeInfo*[T](x: T): pointer {.magic: "GetTypeInfo", benign.}
   ## Get type information for `x`.