new feature: ability to turn specific warnings to errors

Author: Araq

changelog.md

@@ -10,6 +10,7 @@
 
 ## Compiler changes
 
+- Specific warnings can now be turned into errors via `--warningAsError[X]:on|off`.
 
 ## Tool changes
 

compiler/commands.nim

@@ -209,12 +209,18 @@ proc processSpecificNote*(arg: string, state: TSpecialWord, pass: TCmdLinePass,
     incl(conf.modifiedyNotes, n)
     case val
     of "on":
-      incl(conf.notes, n)
-      incl(conf.mainPackageNotes, n)
+      if state == wWarningAsError:
+        incl(conf.warningAsErrors, n)
+      else:
+        incl(conf.notes, n)
+        incl(conf.mainPackageNotes, n)
     of "off":
-      excl(conf.notes, n)
-      excl(conf.mainPackageNotes, n)
-      excl(conf.foreignPackageNotes, n)
+      if state == wWarningAsError:
+        excl(conf.warningAsErrors, n)
+      else:
+        excl(conf.notes, n)
+        excl(conf.mainPackageNotes, n)
+        excl(conf.foreignPackageNotes, n)
 
 proc processCompile(conf: ConfigRef; filename: string) =
   var found = findFile(conf, filename)
@@ -528,6 +534,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     if processOnOffSwitchOrList(conf, {optWarns}, arg, pass, info): listWarnings(conf)
   of "warning": processSpecificNote(arg, wWarning, pass, info, switch, conf)
   of "hint": processSpecificNote(arg, wHint, pass, info, switch, conf)
+  of "warningaserror": processSpecificNote(arg, wWarningAsError, pass, info, switch, conf)
   of "hints":
     if processOnOffSwitchOrList(conf, {optHints}, arg, pass, info): listHints(conf)
   of "threadanalysis": processOnOffSwitchG(conf, {optThreadAnalysis}, arg, pass, info)

compiler/msgs.nim

@@ -354,7 +354,8 @@ proc handleError(conf: ConfigRef; msg: TMsgKind, eh: TErrorHandling, s: string)
   if msg >= fatalMin and msg <= fatalMax:
     if conf.cmd == cmdIdeTools: log(s)
     quit(conf, msg)
-  if msg >= errMin and msg <= errMax:
+  if msg >= errMin and msg <= errMax or
+      (msg in warnMin..warnMax and msg in conf.warningAsErrors):
     inc(conf.errorCounter)
     conf.exitcode = 1'i8
     if conf.errorCounter >= conf.errorMax:
@@ -412,7 +413,7 @@ proc rawMessage*(conf: ConfigRef; msg: TMsgKind, args: openArray[string]) =
     sev = Severity.Warning
     if not conf.hasWarn(msg): return
     writeContext(conf, unknownLineInfo)
-    title = WarningTitle
+    title = if msg in conf.warningAsErrors: ErrorTitle else: WarningTitle
     color = WarningColor
     kind = WarningsToStr[ord(msg) - ord(warnMin)]
     inc(conf.warnCounter)
@@ -500,7 +501,7 @@ proc liMessage(conf: ConfigRef; info: TLineInfo, msg: TMsgKind, arg: string,
     sev = Severity.Warning
     ignoreMsg = not conf.hasWarn(msg)
     if not ignoreMsg: writeContext(conf, info)
-    title = WarningTitle
+    title = if msg in conf.warningAsErrors: ErrorTitle else: WarningTitle
     color = WarningColor
     kind = WarningsToStr[ord(msg) - ord(warnMin)]
     inc(conf.warnCounter)

compiler/options.nim

@@ -237,6 +237,7 @@ type
     cmdlineNotes*: TNoteKinds # notes that have been set/unset from cmdline
     foreignPackageNotes*: TNoteKinds
     notes*: TNoteKinds # notes after resolving all logic(defaults, verbosity)/cmdline/configs
+    warningAsErrors*: TNoteKinds
     mainPackageNotes*: TNoteKinds
     mainPackageId*: int
     errorCounter*: int

compiler/pragmas.nim

@@ -330,31 +330,28 @@ proc processDynLib(c: PContext, n: PNode, sym: PSym) =
       sym.typ.callConv = ccCDecl
 
 proc processNote(c: PContext, n: PNode) =
+  template handleNote(toStrArray, msgMin, notes) =
+    let x = findStr(toStrArray, n[0][1].ident.s)
+    if x >= 0:
+      nk = TNoteKind(x + ord(msgMin))
+      let x = c.semConstBoolExpr(c, n[1])
+      n[1] = x
+      if x.kind == nkIntLit and x.intVal != 0: incl(notes, nk)
+      else: excl(notes, nk)
+    else:
+      invalidPragma(c, n)
+
   if n.kind in nkPragmaCallKinds and n.len == 2 and
       n[0].kind == nkBracketExpr and
       n[0].len == 2 and
       n[0][1].kind == nkIdent and n[0][0].kind == nkIdent:
     var nk: TNoteKind
     case whichKeyword(n[0][0].ident)
-    of wHint:
-      var x = findStr(HintsToStr, n[0][1].ident.s)
-      if x >= 0: nk = TNoteKind(x + ord(hintMin))
-      else: invalidPragma(c, n); return
-    of wWarning:
-      var x = findStr(WarningsToStr, n[0][1].ident.s)
-      if x >= 0: nk = TNoteKind(x + ord(warnMin))
-      else: invalidPragma(c, n); return
-    else:
-      invalidPragma(c, n)
-      return
-
-    let x = c.semConstBoolExpr(c, n[1])
-    n[1] = x
-    if x.kind == nkIntLit and x.intVal != 0: incl(c.config.notes, nk)
-    else: excl(c.config.notes, nk)
-    # checkme: honor cmdlineNotes with: c.setNote(nk, x.kind == nkIntLit and x.intVal != 0)
-  else:
-    invalidPragma(c, n)
+    of wHint: handleNote(HintsToStr, hintMin, c.config.notes)
+    of wWarning: handleNote(WarningsToStr, warnMin, c.config.notes)
+    of wWarningAsError: handleNote(WarningsToStr, warnMin, c.config.warningAsErrors)
+    else: invalidPragma(c, n)
+  else: invalidPragma(c, n)
 
 proc pragmaToOptions(w: TSpecialWord): TOptions {.inline.} =
   case w

compiler/semdata.nim

@@ -21,6 +21,7 @@ type
     notes*: TNoteKinds
     features*: set[Feature]
     otherPragmas*: PNode      # every pragma can be pushed
+    warningAsErrors*: TNoteKinds
 
   POptionEntry* = ref TOptionEntry
   PProcCon* = ref TProcCon
@@ -213,6 +214,7 @@ proc newOptionEntry*(conf: ConfigRef): POptionEntry =
   result.defaultCC = ccDefault
   result.dynlib = nil
   result.notes = conf.notes
+  result.warningAsErrors = conf.warningAsErrors
 
 proc pushOptionEntry*(c: PContext): POptionEntry =
   new(result)
@@ -221,12 +223,14 @@ proc pushOptionEntry*(c: PContext): POptionEntry =
   result.defaultCC = prev.defaultCC
   result.dynlib = prev.dynlib
   result.notes = c.config.notes
+  result.warningAsErrors = c.config.warningAsErrors
   result.features = c.features
   c.optionStack.add(result)
 
 proc popOptionEntry*(c: PContext) =
   c.config.options = c.optionStack[^1].options
   c.config.notes = c.optionStack[^1].notes
+  c.config.warningAsErrors = c.optionStack[^1].warningAsErrors
   c.features = c.optionStack[^1].features
   c.optionStack.setLen(c.optionStack.len - 1)
 

compiler/wordrecg.nim

@@ -44,7 +44,7 @@ type
     wAlign, wNodecl, wPure, wSideEffect, wHeader,
     wNoSideEffect, wGcSafe, wNoreturn, wNosinks, wMerge, wLib, wDynlib,
     wCompilerProc, wCore, wProcVar, wBase, wUsed,
-    wFatal, wError, wWarning, wHint, wLine, wPush, wPop, wDefine, wUndef,
+    wFatal, wError, wWarning, wHint, wWarningAsError, wLine, wPush, wPop, wDefine, wUndef,
     wLineDir, wStackTrace, wLineTrace, wLink, wCompile,
     wLinksys, wDeprecated, wVarargs, wCallconv, wDebugger,
     wNimcall, wStdcall, wCdecl, wSafecall, wSyscall, wInline, wNoInline,
@@ -131,7 +131,7 @@ const
     "requiresinit", "align", "nodecl", "pure", "sideeffect",
     "header", "nosideeffect", "gcsafe", "noreturn", "nosinks", "merge", "lib", "dynlib",
     "compilerproc", "core", "procvar", "base", "used",
-    "fatal", "error", "warning", "hint", "line",
+    "fatal", "error", "warning", "hint", "warningaserror", "line",
     "push", "pop", "define", "undef", "linedir", "stacktrace", "linetrace",
     "link", "compile", "linksys", "deprecated", "varargs",
     "callconv", "debugger", "nimcall", "stdcall",
@@ -212,4 +212,5 @@ proc canonPragmaSpelling*(w: TSpecialWord): string =
   of wCodegenDecl: "codegenDecl"
   of wLiftLocals: "liftLocals"
   of wLocalPassc: "localPassc"
+  of wWarningAsError: "warningAsError"
   else: specialWords[w]

doc/advopt.txt

@@ -38,6 +38,8 @@ Advanced options:
   --warning[X]:on|off       turn specific warning X on|off
   --hints:on|off|list       turn all hints on|off or list all available
   --hint[X]:on|off          turn specific hint X on|off
+  --warningAsError[X]:on|off
+                            turn specific warning X into an error on|off
   --styleCheck:off|hint|error
                             produce hints or errors for Nim identifiers that
                             do not adhere to Nim's official style guide