Make abort() call sites log first

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();
 }