Make abort() call sites log first

src/libcmd/repl.cc

@@ -217,7 +217,7 @@ ReplExitStatus NixRepl::mainLoop()
                 case ProcessLineResult::PromptAgain:
                     break;
                 default:
-                    abort();
+                    unreachable();
             }
         } catch (ParseError & e) {
             if (e.msg().find("unexpected end of file") != std::string::npos) {

src/libexpr/attr-path.cc

@@ -134,7 +134,7 @@ std::pair<SourcePath, uint32_t> findPackageFilename(EvalState & state, Value & v
         return {SourcePath{path.accessor, CanonPath(fn.substr(0, colon))}, lineno};
     } catch (std::invalid_argument & e) {
         fail();
-        abort();
+        unreachable();
     }
 }
 

src/libexpr/eval.cc

@@ -149,7 +149,7 @@ std::string_view showType(ValueType type, bool withArticle)
         case nFloat: return WA("a", "float");
         case nThunk: return WA("a", "thunk");
     }
-    abort();
+    unreachable();
 }
 
 
@@ -771,7 +771,7 @@ void EvalState::runDebugRepl(const Error * error, const Env & env, const Expr &
             case ReplExitStatus::Continue:
                 break;
             default:
-                abort();
+                unreachable();
         }
     }
 }
@@ -1140,7 +1140,7 @@ inline void EvalState::evalAttrs(Env & env, Expr * e, Value & v, const PosIdx po
 
 void Expr::eval(EvalState & state, Env & env, Value & v)
 {
-    abort();
+    unreachable();
 }
 
 
@@ -1573,7 +1573,7 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value &
                                 .withFrame(*fun.payload.lambda.env, lambda)
                                 .debugThrow();
                         }
-                    abort(); // can't happen
+                    unreachable();
                 }
             }
 

src/libexpr/nixexpr.cc

@@ -25,7 +25,7 @@ std::ostream & operator <<(std::ostream & str, const SymbolStr & symbol)
 
 void Expr::show(const SymbolTable & symbols, std::ostream & str) const
 {
-    abort();
+    unreachable();
 }
 
 void ExprInt::show(const SymbolTable & symbols, std::ostream & str) const
@@ -271,7 +271,7 @@ std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath)
 
 void Expr::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
-    abort();
+    unreachable();
 }
 
 void ExprInt::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)

src/libexpr/primops.cc

@@ -426,7 +426,7 @@ static void prim_typeOf(EvalState & state, const PosIdx pos, Value * * args, Val
             t = args[0]->external()->typeOf();
             break;
         case nFloat: t = "float"; break;
-        case nThunk: abort();
+        case nThunk: unreachable();
     }
     v.mkString(t);
 }

src/libexpr/print-ambiguous.cc

@@ -94,7 +94,7 @@ void printAmbiguous(
         break;
     default:
         printError("Nix evaluator internal error: printAmbiguous: invalid value type");
-        abort();
+        unreachable();
     }
 }
 

src/libexpr/print.cc

@@ -475,7 +475,7 @@ private:
             else
                 output << "primop";
         } else {
-            abort();
+            unreachable();
         }
 
         output << "»";
@@ -504,7 +504,7 @@ private:
             if (options.ansiColors)
                     output << ANSI_NORMAL;
         } else {
-            abort();
+            unreachable();
         }
     }
 

src/libexpr/symbol-table.hh

@@ -7,6 +7,7 @@
 
 #include "types.hh"
 #include "chunked-vector.hh"
+#include "error.hh"
 
 namespace nix {
 
@@ -113,7 +114,7 @@ public:
     SymbolStr operator[](Symbol s) const
     {
         if (s.id == 0 || s.id > store.size())
-            abort();
+            unreachable();
         return SymbolStr(store[s.id - 1]);
     }
 

src/libexpr/value.hh

@@ -285,7 +285,7 @@ public:
         if (invalidIsThunk)
             return nThunk;
         else
-            abort();
+            unreachable();
     }
 
     inline void finishValue(InternalType newType, Payload newPayload)

src/libfetchers/attrs.cc

@@ -33,7 +33,7 @@ nlohmann::json attrsToJSON(const Attrs & attrs)
             json[attr.first] = *v;
         } else if (auto v = std::get_if<Explicit<bool>>(&attr.second)) {
             json[attr.first] = v->t;
-        } else abort();
+        } else unreachable();
     }
     return json;
 }
@@ -99,7 +99,7 @@ std::map<std::string, std::string> attrsToQuery(const Attrs & attrs)
             query.insert_or_assign(attr.first, *v);
         } else if (auto v = std::get_if<Explicit<bool>>(&attr.second)) {
             query.insert_or_assign(attr.first, v->t ? "1" : "0");
-        } else abort();
+        } else unreachable();
     }
     return query;
 }

src/libmain/loggers.cc

@@ -36,7 +36,7 @@ Logger * makeDefaultLogger() {
         return logger;
     }
     default:
-        abort();
+        unreachable();
     }
 }
 

src/libstore/build/drv-output-substitution-goal.hh

@@ -36,7 +36,7 @@ public:
     Co init() override;
     Co realisationFetched(std::shared_ptr<const Realisation> outputInfo, nix::ref<nix::Store> sub);
 
-    void timedOut(Error && ex) override { abort(); };
+    void timedOut(Error && ex) override { unreachable(); };
 
     std::string key() override;
 

src/libstore/build/goal.hh

@@ -400,12 +400,12 @@ public:
 
     virtual void handleChildOutput(Descriptor fd, std::string_view data)
     {
-        abort();
+        unreachable();
     }
 
     virtual void handleEOF(Descriptor fd)
     {
-        abort();
+        unreachable();
     }
 
     void trace(std::string_view s);

src/libstore/build/substitution-goal.hh

@@ -50,7 +50,7 @@ public:
     PathSubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
     ~PathSubstitutionGoal();
 
-    void timedOut(Error && ex) override { abort(); };
+    void timedOut(Error && ex) override { unreachable(); };
 
     /**
      * We prepend "a$" to the key name to ensure substitution goals

src/libstore/build/worker.cc

@@ -216,7 +216,7 @@ void Worker::childStarted(GoalPtr goal, const std::set<MuxablePipePollState::Com
             nrLocalBuilds++;
             break;
         default:
-            abort();
+            unreachable();
         }
     }
 }
@@ -239,7 +239,7 @@ void Worker::childTerminated(Goal * goal, bool wakeSleepers)
             nrLocalBuilds--;
             break;
         default:
-            abort();
+            unreachable();
         }
     }
 

src/libstore/daemon.cc

@@ -33,7 +33,7 @@ Sink & operator << (Sink & sink, const Logger::Fields & fields)
             sink << f.i;
         else if (f.type == Logger::Field::tString)
             sink << f.s;
-        else abort();
+        else unreachable();
     }
     return sink;
 }

src/libstore/gc.cc

@@ -559,7 +559,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
                        non-blocking flag from the server socket, so
                        explicitly make it blocking. */
                     if (fcntl(fdClient.get(), F_SETFL, fcntl(fdClient.get(), F_GETFL) & ~O_NONBLOCK) == -1)
-                        abort();
+                        panic("Could not set non-blocking flag on client socket");
 
                     while (true) {
                         try {

src/libstore/globals.cc

@@ -297,7 +297,7 @@ template<> std::string BaseSetting<SandboxMode>::to_string() const
     if (value == smEnabled) return "true";
     else if (value == smRelaxed) return "relaxed";
     else if (value == smDisabled) return "false";
-    else abort();
+    else unreachable();
 }
 
 template<> void BaseSetting<SandboxMode>::convertToArg(Args & args, const std::string & category)

src/libstore/nar-info-disk-cache.cc

@@ -164,7 +164,7 @@ public:
     Cache & getCache(State & state, const std::string & uri)
     {
         auto i = state.caches.find(uri);
-        if (i == state.caches.end()) abort();
+        if (i == state.caches.end()) unreachable();
         return i->second;
     }
 
@@ -211,7 +211,7 @@ public:
 
             {
                 auto r(state->insertCache.use()(uri)(time(0))(storeDir)(wantMassQuery)(priority));
-                if (!r.next()) { abort(); }
+                if (!r.next()) { unreachable(); }
                 ret.id = (int) r.getInt(0);
             }
 

src/libstore/unix/build/local-derivation-goal.cc

@@ -165,7 +165,7 @@ void LocalDerivationGoal::killSandbox(bool getStats)
             buildResult.cpuSystem = stats.cpuSystem;
         }
         #else
-        abort();
+        unreachable();
         #endif
     }
 

src/libstore/unix/pathlocks.cc

@@ -45,7 +45,7 @@ bool lockFile(Descriptor desc, LockType lockType, bool wait)
     if (lockType == ltRead) type = LOCK_SH;
     else if (lockType == ltWrite) type = LOCK_EX;
     else if (lockType == ltNone) type = LOCK_UN;
-    else abort();
+    else unreachable();
 
     if (wait) {
         while (flock(desc, type) != 0) {

src/libutil/chunked-vector.hh

@@ -6,6 +6,8 @@
 #include <vector>
 #include <limits>
 
+#include "error.hh"
+
 namespace nix {
 
 /**
@@ -30,7 +32,7 @@ private:
     auto & addChunk()
     {
         if (size_ >= std::numeric_limits<uint32_t>::max() - ChunkSize)
-            abort();
+            unreachable();
         chunks.emplace_back();
         chunks.back().reserve(ChunkSize);
         return chunks.back();

src/libutil/error.cc

@@ -430,4 +430,16 @@ std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool s
     return out;
 }
 
+void panic(std::string_view msg)
+{
+    printError(msg);
+    printError("This was a fatal error, aborting.");
+    abort();
+}
+
+void panic(const char * file, int line, const char * func)
+{
+    panic(std::string("Unexpected condition in ") + func + " at " + file + ":" + std::to_string(line));
+}
+
 }

src/libutil/error.hh

@@ -273,4 +273,28 @@ using NativeSysError =
  */
 void throwExceptionSelfCheck();
 
+/**
+ * Print a message and abort().
+ *
+ * @note: This assumes that the logger is operational
+ */
+[[noreturn]]
+void panic(std::string_view msg);
+
+/**
+ * Print a basic error message with source position and abort().
+ * Use the unreachable macro to call this.
+ *
+ * @note: This assumes that the logger is operational
+ */
+[[noreturn]]
+void panic(const char * file, int line, const char * func);
+
+/**
+ * Print a basic error message with source position and abort().
+ *
+ * @note: This assumes that the logger is operational
+ */
+#define unreachable() (panic(__FILE__, __LINE__, __func__))
+
 }

src/libutil/file-content-address.cc

@@ -63,7 +63,7 @@ std::string_view renderFileIngestionMethod(FileIngestionMethod method)
     case FileIngestionMethod::Git:
         return "git";
     default:
-        abort();
+        unreachable();
     }
 }
 

src/libutil/fs-sink.cc

@@ -53,7 +53,7 @@ void copyRecursive(
         throw Error("file '%1%' has an unsupported type", from);
 
     default:
-        abort();
+        unreachable();
     }
 }
 

src/libutil/git.cc

@@ -201,7 +201,7 @@ std::optional<Mode> convertMode(SourceAccessor::Type type)
     case SourceAccessor::tRegular:   return Mode::Regular;
     case SourceAccessor::tDirectory: return Mode::Directory;
     case SourceAccessor::tMisc:      return std::nullopt;
-    default: abort();
+    default: unreachable();
     }
 }
 

src/libutil/hash.cc

@@ -25,7 +25,7 @@ static size_t regularHashSize(HashAlgorithm type) {
     case HashAlgorithm::SHA256: return sha256HashSize;
     case HashAlgorithm::SHA512: return sha512HashSize;
     }
-    abort();
+    unreachable();
 }
 
 

src/libutil/logging.cc

@@ -189,7 +189,7 @@ struct JSONLogger : Logger {
             else if (f.type == Logger::Field::tString)
                 arr.push_back(f.s);
             else
-                abort();
+                unreachable();
     }
 
     void write(const nlohmann::json & json)

src/libutil/serialise.cc

@@ -260,7 +260,7 @@ std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
                 });
             }
 
-            if (!*coro) { abort(); }
+            if (!*coro) { unreachable(); }
 
             if (!cur.empty()) {
                 CoroutineContext ctx;
@@ -271,12 +271,12 @@ std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
         void finish() override
         {
             if (!coro) return;
-            if (!*coro) abort();
+            if (!*coro) unreachable();
             {
                 CoroutineContext ctx;
                 (*coro)(true);
             }
-            if (*coro) abort();
+            if (*coro) unreachable();
         }
     };
 
@@ -316,7 +316,7 @@ std::unique_ptr<Source> sinkToSource(
                 });
             }
 
-            if (!*coro) { eof(); abort(); }
+            if (!*coro) { eof(); unreachable(); }
 
             if (pos == cur.size()) {
                 if (!cur.empty()) {

src/libutil/sync.hh

@@ -7,6 +7,8 @@
 #include <condition_variable>
 #include <cassert>
 
+#include "error.hh"
+
 namespace nix {
 
 /**
@@ -47,7 +49,7 @@ public:
         friend SyncBase;
         Lock(SyncBase * s) : s(s), lk(s->mutex) { }
     public:
-        Lock(Lock && l) : s(l.s) { abort(); }
+        Lock(Lock && l) : s(l.s) { unreachable(); }
         Lock(const Lock & l) = delete;
         ~Lock() { }
 

src/libutil/unix/monitor-fd.hh

@@ -40,7 +40,9 @@ public:
                     #endif
                     ;
                 auto count = poll(fds, 1, -1);
-                if (count == -1) abort(); // can't happen
+                if (count == -1)
+                    unreachable();
+
                 /* This shouldn't happen, but can on macOS due to a bug.
                    See rdar://37550628.
 

src/libutil/unix/processes.cc

@@ -182,7 +182,7 @@ static pid_t doFork(bool allowVfork, ChildWrapperFunction & fun)
 #endif
     if (pid != 0) return pid;
     fun();
-    abort();
+    unreachable();
 }
 
 

src/nix-env/nix-env.cc

@@ -1159,7 +1159,7 @@ static void opQuery(Globals & globals, Strings opFlags, Strings opArgs)
                     case cvEqual: ch = '='; break;
                     case cvGreater: ch = '<'; break;
                     case cvUnavail: ch = '-'; break;
-                    default: abort();
+                    default: unreachable();
                 }
 
                 if (xmlOutput) {

src/nix-store/nix-store.cc

@@ -480,7 +480,7 @@ static void opQuery(Strings opFlags, Strings opArgs)
         }
 
         default:
-            abort();
+            unreachable();
     }
 }