From e8657c7107761fae7a8b5559df3b88165c238a12 Mon Sep 17 00:00:00 2001
From: ee7 <45465154+ee7@users.noreply.github.com>
Date: Fri, 19 Aug 2022 21:40:53 +0200
Subject: make implicit cstring conversions explicit (#19488)

The Nim manual says that an implicit conversion to cstring will
eventually not be allowed [1]:

    A Nim `string` is implicitly convertible to `cstring` for convenience.

    [...]

    Even though the conversion is implicit, it is not *safe*: The garbage collector
    does not consider a `cstring` to be a root and may collect the underlying
    memory. For this reason, the implicit conversion will be removed in future
    releases of the Nim compiler. Certain idioms like conversion of a `const` string
    to `cstring` are safe and will remain to be allowed.

And from Nim 1.6.0, such a conversion triggers a warning [2]:

    A dangerous implicit conversion to `cstring` now triggers a `[CStringConv]` warning.
    This warning will become an error in future versions! Use an explicit conversion
    like `cstring(x)` in order to silence the warning.

However, some files in this repo produced such a warning. For example,
before this commit, compiling `parsejson.nim` would produce:

    /foo/Nim/lib/pure/parsejson.nim(221, 37) Warning: implicit conversion to 'cstring' from a non-const location: my.buf; this will become a compile time error in the future [CStringConv]
    /foo/Nim/lib/pure/parsejson.nim(231, 39) Warning: implicit conversion to 'cstring' from a non-const location: my.buf; this will become a compile time error in the future [CStringConv]

This commit resolves the most visible `CStringConv` warnings, making the
cstring conversions explicit.

[1] https://github.com/nim-lang/Nim/blob/d2318d9ccfe6/doc/manual.md#cstring-type
[2] https://github.com/nim-lang/Nim/blob/d2318d9ccfe6/changelogs/changelog_1_6_0.md#type-system
---
 lib/impure/db_mysql.nim    | 10 +++++-----
 lib/impure/db_odbc.nim     |  2 +-
 lib/impure/db_postgres.nim | 24 ++++++++++++------------
 lib/impure/db_sqlite.nim   |  6 +++---
 lib/nimhcr.nim             | 14 +++++++-------
 lib/pure/logging.nim       |  2 +-
 lib/pure/nativesockets.nim |  6 +++---
 lib/pure/net.nim           |  2 +-
 lib/pure/os.nim            | 20 ++++++++++----------
 lib/pure/osproc.nim        | 10 +++++-----
 lib/pure/parsejson.nim     |  4 ++--
 11 files changed, 50 insertions(+), 50 deletions(-)

(limited to 'lib')

diff --git a/lib/impure/db_mysql.nim b/lib/impure/db_mysql.nim
index 562847e6b..223c5dcf8 100644
--- a/lib/impure/db_mysql.nim
+++ b/lib/impure/db_mysql.nim
@@ -149,17 +149,17 @@ proc tryExec*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): bool {.
   tags: [ReadDbEffect, WriteDbEffect].} =
   ## tries to execute the query and returns true if successful, false otherwise.
   var q = dbFormat(query, args)
-  return mysql.real_query(PMySQL db, q, q.len) == 0'i32
+  return mysql.real_query(PMySQL db, q.cstring, q.len) == 0'i32
 
 proc rawExec(db: DbConn, query: SqlQuery, args: varargs[string, `$`]) =
   var q = dbFormat(query, args)
-  if mysql.real_query(PMySQL db, q, q.len) != 0'i32: dbError(db)
+  if mysql.real_query(PMySQL db, q.cstring, q.len) != 0'i32: dbError(db)
 
 proc exec*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]) {.
   tags: [ReadDbEffect, WriteDbEffect].} =
   ## executes the query and raises EDB if not successful.
   var q = dbFormat(query, args)
-  if mysql.real_query(PMySQL db, q, q.len) != 0'i32: dbError(db)
+  if mysql.real_query(PMySQL db, q.cstring, q.len) != 0'i32: dbError(db)
 
 proc newRow(L: int): Row =
   newSeq(result, L)
@@ -360,7 +360,7 @@ proc tryInsertId*(db: DbConn, query: SqlQuery,
   ## executes the query (typically "INSERT") and returns the
   ## generated ID for the row or -1 in case of an error.
   var q = dbFormat(query, args)
-  if mysql.real_query(PMySQL db, q, q.len) != 0'i32:
+  if mysql.real_query(PMySQL db, q.cstring, q.len) != 0'i32:
     result = -1'i64
   else:
     result = mysql.insertId(PMySQL db)
@@ -409,7 +409,7 @@ proc open*(connection, user, password, database: string): DbConn {.
            else: substr(connection, 0, colonPos-1)
     port: int32 = if colonPos < 0: 0'i32
                   else: substr(connection, colonPos+1).parseInt.int32
-  if mysql.realConnect(res, host, user, password, database,
+  if mysql.realConnect(res, host.cstring, user, password, database,
                        port, nil, 0) == nil:
     var errmsg = $mysql.error(res)
     mysql.close(res)
diff --git a/lib/impure/db_odbc.nim b/lib/impure/db_odbc.nim
index 1e4032b34..0ecd8129f 100644
--- a/lib/impure/db_odbc.nim
+++ b/lib/impure/db_odbc.nim
@@ -334,7 +334,7 @@ proc `[]`*(row: InstantRow, col: int): string {.inline.} =
 
 proc unsafeColumnAt*(row: InstantRow, index: int): cstring {.inline.} =
   ## Return cstring of given column of the row
-  row.row[index]
+  row.row[index].cstring
 
 proc len*(row: InstantRow): int {.inline.} =
   ## Returns number of columns in the row
diff --git a/lib/impure/db_postgres.nim b/lib/impure/db_postgres.nim
index 36e035d3d..82403ab00 100644
--- a/lib/impure/db_postgres.nim
+++ b/lib/impure/db_postgres.nim
@@ -133,7 +133,7 @@ proc dbFormat(formatstr: SqlQuery, args: varargs[string]): string =
 proc tryExec*(db: DbConn, query: SqlQuery,
               args: varargs[string, `$`]): bool {.tags: [ReadDbEffect, WriteDbEffect].} =
   ## tries to execute the query and returns true if successful, false otherwise.
-  var res = pqexecParams(db, dbFormat(query, args), 0, nil, nil,
+  var res = pqexecParams(db, dbFormat(query, args).cstring, 0, nil, nil,
                         nil, nil, 0)
   result = pqresultStatus(res) == PGRES_COMMAND_OK
   pqclear(res)
@@ -143,7 +143,7 @@ proc tryExec*(db: DbConn, stmtName: SqlPrepared,
               ReadDbEffect, WriteDbEffect].} =
   ## tries to execute the query and returns true if successful, false otherwise.
   var arr = allocCStringArray(args)
-  var res = pqexecPrepared(db, stmtName.string, int32(args.len), arr,
+  var res = pqexecPrepared(db, stmtName.cstring, int32(args.len), arr,
                            nil, nil, 0)
   deallocCStringArray(arr)
   result = pqresultStatus(res) == PGRES_COMMAND_OK
@@ -152,7 +152,7 @@ proc tryExec*(db: DbConn, stmtName: SqlPrepared,
 proc exec*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]) {.
   tags: [ReadDbEffect, WriteDbEffect].} =
   ## executes the query and raises EDB if not successful.
-  var res = pqexecParams(db, dbFormat(query, args), 0, nil, nil,
+  var res = pqexecParams(db, dbFormat(query, args).cstring, 0, nil, nil,
                         nil, nil, 0)
   if pqresultStatus(res) != PGRES_COMMAND_OK: dbError(db)
   pqclear(res)
@@ -160,7 +160,7 @@ proc exec*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]) {.
 proc exec*(db: DbConn, stmtName: SqlPrepared,
           args: varargs[string]) {.tags: [ReadDbEffect, WriteDbEffect].} =
   var arr = allocCStringArray(args)
-  var res = pqexecPrepared(db, stmtName.string, int32(args.len), arr,
+  var res = pqexecPrepared(db, stmtName.cstring, int32(args.len), arr,
                            nil, nil, 0)
   deallocCStringArray(arr)
   if pqResultStatus(res) != PGRES_COMMAND_OK: dbError(db)
@@ -172,20 +172,20 @@ proc newRow(L: int): Row =
 
 proc setupQuery(db: DbConn, query: SqlQuery,
                 args: varargs[string]): PPGresult =
-  result = pqexec(db, dbFormat(query, args))
+  result = pqexec(db, dbFormat(query, args).cstring)
   if pqResultStatus(result) != PGRES_TUPLES_OK: dbError(db)
 
 proc setupQuery(db: DbConn, stmtName: SqlPrepared,
                  args: varargs[string]): PPGresult =
   var arr = allocCStringArray(args)
-  result = pqexecPrepared(db, stmtName.string, int32(args.len), arr,
+  result = pqexecPrepared(db, stmtName.cstring, int32(args.len), arr,
                           nil, nil, 0)
   deallocCStringArray(arr)
   if pqResultStatus(result) != PGRES_TUPLES_OK: dbError(db)
 
 proc setupSingeRowQuery(db: DbConn, query: SqlQuery,
                         args: varargs[string]) =
-  if pqsendquery(db, dbFormat(query, args)) != 1:
+  if pqsendquery(db, dbFormat(query, args).cstring) != 1:
     dbError(db)
   if pqSetSingleRowMode(db) != 1:
     dbError(db)
@@ -193,7 +193,7 @@ proc setupSingeRowQuery(db: DbConn, query: SqlQuery,
 proc setupSingeRowQuery(db: DbConn, stmtName: SqlPrepared,
                        args: varargs[string]) =
   var arr = allocCStringArray(args)
-  if pqsendqueryprepared(db, stmtName.string, int32(args.len), arr, nil, nil, 0) != 1:
+  if pqsendqueryprepared(db, stmtName.cstring, int32(args.len), arr, nil, nil, 0) != 1:
     dbError(db)
   if pqSetSingleRowMode(db) != 1:
     dbError(db)
@@ -205,7 +205,7 @@ proc prepare*(db: DbConn; stmtName: string, query: SqlQuery;
   ## via `$1`, `$2`, `$3`, etc.
   if nParams > 0 and not string(query).contains("$1"):
     dbError("parameter substitution expects \"$1\"")
-  var res = pqprepare(db, stmtName, query.string, int32(nParams), nil)
+  var res = pqprepare(db, stmtName, query.cstring, int32(nParams), nil)
   if pqResultStatus(res) != PGRES_COMMAND_OK: dbError(db)
   return SqlPrepared(stmtName)
 
@@ -590,7 +590,7 @@ proc execAffectedRows*(db: DbConn, query: SqlQuery,
   ## executes the query (typically "UPDATE") and returns the
   ## number of affected rows.
   var q = dbFormat(query, args)
-  var res = pqExec(db, q)
+  var res = pqExec(db, q.cstring)
   if pqresultStatus(res) != PGRES_COMMAND_OK: dbError(db)
   result = parseBiggestInt($pqcmdTuples(res))
   pqclear(res)
@@ -601,7 +601,7 @@ proc execAffectedRows*(db: DbConn, stmtName: SqlPrepared,
   ## executes the query (typically "UPDATE") and returns the
   ## number of affected rows.
   var arr = allocCStringArray(args)
-  var res = pqexecPrepared(db, stmtName.string, int32(args.len), arr,
+  var res = pqexecPrepared(db, stmtName.cstring, int32(args.len), arr,
                            nil, nil, 0)
   deallocCStringArray(arr)
   if pqresultStatus(res) != PGRES_COMMAND_OK: dbError(db)
@@ -634,7 +634,7 @@ proc open*(connection, user, password, database: string): DbConn {.
            else: substr(connection, 0, colonPos-1)
     port = if colonPos < 0: ""
            else: substr(connection, colonPos+1)
-  result = pqsetdbLogin(host, port, nil, nil, database, user, password)
+  result = pqsetdbLogin(host.cstring, port.cstring, nil, nil, database, user, password)
   if pqStatus(result) != CONNECTION_OK: dbError(result) # result = nil
 
 proc setEncoding*(connection: DbConn, encoding: string): bool {.
diff --git a/lib/impure/db_sqlite.nim b/lib/impure/db_sqlite.nim
index 1638d38c6..f79e87f1b 100644
--- a/lib/impure/db_sqlite.nim
+++ b/lib/impure/db_sqlite.nim
@@ -235,7 +235,7 @@ proc tryExec*(db: DbConn, query: SqlQuery,
   assert(not db.isNil, "Database not connected.")
   var q = dbFormat(query, args)
   var stmt: sqlite3.PStmt
-  if prepare_v2(db, q, q.len.cint, stmt, nil) == SQLITE_OK:
+  if prepare_v2(db, q.cstring, q.len.cint, stmt, nil) == SQLITE_OK:
     let x = step(stmt)
     if x in {SQLITE_DONE, SQLITE_ROW}:
       result = finalize(stmt) == SQLITE_OK
@@ -278,7 +278,7 @@ proc setupQuery(db: DbConn, query: SqlQuery,
                 args: varargs[string]): PStmt =
   assert(not db.isNil, "Database not connected.")
   var q = dbFormat(query, args)
-  if prepare_v2(db, q, q.len.cint, result, nil) != SQLITE_OK: dbError(db)
+  if prepare_v2(db, q.cstring, q.len.cint, result, nil) != SQLITE_OK: dbError(db)
 
 proc setupQuery(db: DbConn, stmtName: SqlPrepared): SqlPrepared {.since: (1, 3).} =
   assert(not db.isNil, "Database not connected.")
@@ -653,7 +653,7 @@ proc tryInsertID*(db: DbConn, query: SqlQuery,
   var q = dbFormat(query, args)
   var stmt: sqlite3.PStmt
   result = -1
-  if prepare_v2(db, q, q.len.cint, stmt, nil) == SQLITE_OK:
+  if prepare_v2(db, q.cstring, q.len.cint, stmt, nil) == SQLITE_OK:
     if step(stmt) == SQLITE_DONE:
       result = last_insert_rowid(db)
     if finalize(stmt) != SQLITE_OK:
diff --git a/lib/nimhcr.nim b/lib/nimhcr.nim
index 2846f931b..b35ecf8df 100644
--- a/lib/nimhcr.nim
+++ b/lib/nimhcr.nim
@@ -487,7 +487,7 @@ when defined(createNimHcr):
           recursiveDiscovery(modules[curr].imports)
           allModulesOrderedByDFS.add(curr)
           continue
-      loadDll(curr)
+      loadDll(curr.cstring)
       # first load all dependencies of the current module and init it after that
       recursiveDiscovery(modules[curr].imports)
 
@@ -497,20 +497,20 @@ when defined(createNimHcr):
   proc initModules() =
     # first init the pointers to hcr functions and also do the registering of typeinfo globals
     for curr in modulesToInit:
-      initHcrData(curr)
-      initTypeInfoGlobals(curr)
+      initHcrData(curr.cstring)
+      initTypeInfoGlobals(curr.cstring)
     # for now system always gets fully inited before any other module (including when reloading)
-    initPointerData(system)
-    initGlobalScope(system)
+    initPointerData(system.cstring)
+    initGlobalScope(system.cstring)
     # proceed with the DatInit calls - for all modules - including the main one!
     for curr in allModulesOrderedByDFS:
       if curr != system:
-        initPointerData(curr)
+        initPointerData(curr.cstring)
     mainDatInit()
     # execute top-level code (in global scope)
     for curr in modulesToInit:
       if curr != system:
-        initGlobalScope(curr)
+        initGlobalScope(curr.cstring)
     # cleanup old symbols which are gone now
     for curr in modulesToInit:
       cleanupSymbols(curr)
diff --git a/lib/pure/logging.nim b/lib/pure/logging.nim
index 6751a372a..cbe8a827a 100644
--- a/lib/pure/logging.nim
+++ b/lib/pure/logging.nim
@@ -367,7 +367,7 @@ method log*(logger: ConsoleLogger, level: Level, args: varargs[string, `$`]) =
   if level >= logging.level and level >= logger.levelThreshold:
     let ln = substituteLog(logger.fmtStr, level, args)
     when defined(js):
-      let cln: cstring = ln
+      let cln = ln.cstring
       case level
       of lvlDebug: {.emit: "console.debug(`cln`);".}
       of lvlInfo:  {.emit: "console.info(`cln`);".}
diff --git a/lib/pure/nativesockets.nim b/lib/pure/nativesockets.nim
index 39438a04e..ca4e61621 100644
--- a/lib/pure/nativesockets.nim
+++ b/lib/pure/nativesockets.nim
@@ -300,7 +300,7 @@ proc getAddrInfo*(address: string, port: Port, domain: Domain = AF_INET,
     if domain == AF_INET6:
       hints.ai_flags = AI_V4MAPPED
   let socketPort = if sockType == SOCK_RAW: "" else: $port
-  var gaiResult = getaddrinfo(address, socketPort, addr(hints), result)
+  var gaiResult = getaddrinfo(address, socketPort.cstring, addr(hints), result)
   if gaiResult != 0'i32:
     when useWinVersion or defined(freertos):
       raiseOSError(osLastError())
@@ -460,10 +460,10 @@ when not useNimNetLite:
     const size = 256
     result = newString(size)
     when useWinVersion:
-      let success = winlean.gethostname(result, size)
+      let success = winlean.gethostname(result.cstring, size)
     else:
       # Posix
-      let success = posix.gethostname(result, size)
+      let success = posix.gethostname(result.cstring, size)
     if success != 0.cint:
       raiseOSError(osLastError())
     let x = len(cstring(result))
diff --git a/lib/pure/net.nim b/lib/pure/net.nim
index 370b83e54..7b50b8ba6 100644
--- a/lib/pure/net.nim
+++ b/lib/pure/net.nim
@@ -682,7 +682,7 @@ when defineSsl:
           var found = false
           let useEnvVars = (if verifyMode == CVerifyPeerUseEnvVars: true else: false)
           for fn in scanSSLCertificates(useEnvVars = useEnvVars):
-            if newCTX.SSL_CTX_load_verify_locations(fn, nil) == VerifySuccess:
+            if newCTX.SSL_CTX_load_verify_locations(fn.cstring, nil) == VerifySuccess:
               found = true
               break
           if not found:
diff --git a/lib/pure/os.nim b/lib/pure/os.nim
index 79f9950a7..82ccd9051 100644
--- a/lib/pure/os.nim
+++ b/lib/pure/os.nim
@@ -1259,12 +1259,12 @@ proc findExe*(exe: string, followSymlinks: bool = true;
           while followSymlinks: # doubles as if here
             if x.symlinkExists:
               var r = newString(maxSymlinkLen)
-              var len = readlink(x, r, maxSymlinkLen)
+              var len = readlink(x.cstring, r.cstring, maxSymlinkLen)
               if len < 0:
                 raiseOSError(osLastError(), exe)
               if len > maxSymlinkLen:
                 r = newString(len+1)
-                len = readlink(x, r, len)
+                len = readlink(x.cstring, r.cstring, len)
               setLen(r, len)
               if isAbsolute(r):
                 x = r
@@ -1404,8 +1404,8 @@ when not defined(nimscript):
       var bufsize = 1024 # should be enough
       result = newString(bufsize)
       while true:
-        if getcwd(result, bufsize) != nil:
-          setLen(result, c_strlen(result))
+        if getcwd(result.cstring, bufsize) != nil:
+          setLen(result, c_strlen(result.cstring))
           break
         else:
           let err = osLastError()
@@ -1774,12 +1774,12 @@ proc expandSymlink*(symlinkPath: string): string {.noWeirdTarget.} =
     result = symlinkPath
   else:
     result = newString(maxSymlinkLen)
-    var len = readlink(symlinkPath, result, maxSymlinkLen)
+    var len = readlink(symlinkPath, result.cstring, maxSymlinkLen)
     if len < 0:
       raiseOSError(osLastError(), symlinkPath)
     if len > maxSymlinkLen:
       result = newString(len+1)
-      len = readlink(symlinkPath, result, len)
+      len = readlink(symlinkPath, result.cstring, len)
     setLen(result, len)
 
 const hasCCopyfile = defined(osx) and not defined(nimLegacyCopyFile)
@@ -2344,7 +2344,7 @@ iterator walkDir*(dir: string; relative = false, checkDir = false):
             var k = pcFile
 
             template kSetGeneric() =  # pure Posix component `k` resolution
-              if lstat(path, s) < 0'i32: continue  # don't yield
+              if lstat(path.cstring, s) < 0'i32: continue  # don't yield
               elif S_ISDIR(s.st_mode):
                 k = pcDir
               elif S_ISLNK(s.st_mode):
@@ -3041,10 +3041,10 @@ when not weirdTarget and (defined(freebsd) or defined(dragonfly) or defined(netb
 when not weirdTarget and (defined(linux) or defined(solaris) or defined(bsd) or defined(aix)):
   proc getApplAux(procPath: string): string =
     result = newString(maxSymlinkLen)
-    var len = readlink(procPath, result, maxSymlinkLen)
+    var len = readlink(procPath, result.cstring, maxSymlinkLen)
     if len > maxSymlinkLen:
       result = newString(len+1)
-      len = readlink(procPath, result, len)
+      len = readlink(procPath, result.cstring, len)
     setLen(result, len)
 
 when not weirdTarget and defined(openbsd):
@@ -3169,7 +3169,7 @@ proc getAppFilename*(): string {.rtl, extern: "nos$1", tags: [ReadIOEffect], noW
     var size = cuint32(0)
     getExecPath1(nil, size)
     result = newString(int(size))
-    if getExecPath2(result, size):
+    if getExecPath2(result.cstring, size):
       result = "" # error!
     if result.len > 0:
       result = result.expandFilename
diff --git a/lib/pure/osproc.nim b/lib/pure/osproc.nim
index 666ccdda8..a0079cf95 100644
--- a/lib/pure/osproc.nim
+++ b/lib/pure/osproc.nim
@@ -1086,9 +1086,9 @@ elif not defined(useNimRtl):
       var pid: Pid
 
       if (poUsePath in data.options):
-        res = posix_spawnp(pid, data.sysCommand, fops, attr, data.sysArgs, data.sysEnv)
+        res = posix_spawnp(pid, data.sysCommand.cstring, fops, attr, data.sysArgs, data.sysEnv)
       else:
-        res = posix_spawn(pid, data.sysCommand, fops, attr, data.sysArgs, data.sysEnv)
+        res = posix_spawn(pid, data.sysCommand.cstring, fops, attr, data.sysArgs, data.sysEnv)
 
       discard posix_spawn_file_actions_destroy(fops)
       discard posix_spawnattr_destroy(attr)
@@ -1174,14 +1174,14 @@ elif not defined(useNimRtl):
         when defined(uClibc) or defined(linux) or defined(haiku):
           # uClibc environment (OpenWrt included) doesn't have the full execvpe
           let exe = findExe(data.sysCommand)
-          discard execve(exe, data.sysArgs, data.sysEnv)
+          discard execve(exe.cstring, data.sysArgs, data.sysEnv)
         else:
           # MacOSX doesn't have execvpe, so we need workaround.
           # On MacOSX we can arrive here only from fork, so this is safe:
           environ = data.sysEnv
-          discard execvp(data.sysCommand, data.sysArgs)
+          discard execvp(data.sysCommand.cstring, data.sysArgs)
       else:
-        discard execve(data.sysCommand, data.sysArgs, data.sysEnv)
+        discard execve(data.sysCommand.cstring, data.sysArgs, data.sysEnv)
 
       startProcessFail(data)
     {.pop.}
diff --git a/lib/pure/parsejson.nim b/lib/pure/parsejson.nim
index c92eac26e..fcbcf8e36 100644
--- a/lib/pure/parsejson.nim
+++ b/lib/pure/parsejson.nim
@@ -221,7 +221,7 @@ proc parseString(my: var JsonParser): TokKind =
           add(my.a, 'u')
         inc(pos, 2)
         var pos2 = pos
-        var r = parseEscapedUTF16(my.buf, pos)
+        var r = parseEscapedUTF16(cstring(my.buf), pos)
         if r < 0:
           my.err = errInvalidToken
           break
@@ -231,7 +231,7 @@ proc parseString(my: var JsonParser): TokKind =
             my.err = errInvalidToken
             break
           inc(pos, 2)
-          var s = parseEscapedUTF16(my.buf, pos)
+          var s = parseEscapedUTF16(cstring(my.buf), pos)
           if (s and 0xfc00) == 0xdc00 and s > 0:
             r = 0x10000 + (((r - 0xd800) shl 10) or (s - 0xdc00))
           else:
-- 
cgit 1.4.1-2-gfad0