Merge pull request #14998 from NixOS/fix-remote-store-nar-from-path

libstore: Do not mark connections as bad when RemoteStore::narFromPath is called as a coroutine

src/libstore/remote-store.cc

@@ -58,8 +58,13 @@ RemoteStore::RemoteStore(const Config & config)
 
 ref<RemoteStore::Connection> RemoteStore::openConnectionWrapper()
 {
-    if (failed)
+    if (failed) {
+        checkInterrupt();
+        /* Throw Interrupted instead of the following error to silence pesky
+           warning messages that ThreadPool prints on shutdown if other threads
+           failed. */
         throw Error("opening a connection to remote store '%s' previously failed", config.getHumanReadableURI());
+    }
     try {
         return openConnection();
     } catch (...) {

src/libutil/include/nix/util/processes.hh

@@ -44,8 +44,8 @@ public:
     void operator=(AutoCloseFD pid);
 #endif
     ~Pid();
-    int kill();
-    int wait();
+    int kill(bool allowInterrupts = true);
+    int wait(bool allowInterrupts = true);
 
     // TODO: Implement for Windows
 #ifndef _WIN32

src/libutil/serialise.cc

@@ -412,7 +412,7 @@ std::unique_ptr<Source> sinkToSource(std::function<void(Sink &)> fun, std::funct
             }
 
             if (cur.empty()) {
-                if (hasCoro) {
+                if (hasCoro && *coro) {
                     (*coro)();
                 }
                 if (*coro) {
@@ -427,6 +427,16 @@ std::unique_ptr<Source> sinkToSource(std::function<void(Sink &)> fun, std::funct
             size_t n = cur.copy(data, len);
             cur.remove_prefix(n);
 
+            /* This is necessary to ensure that the coroutine gets resumed
+               after the consumer has finished reading the Source. Otherwise the
+               coroutine is always abandoned (i.e. it is always destroyed when
+               suspended). */
+            if (cur.empty() && coro && *coro) {
+                (*coro)();
+                if (*coro)
+                    cur = coro->get();
+            }
+
             return n;
         }
     };

src/libutil/unix/processes.cc

@@ -41,9 +41,11 @@ Pid::Pid(pid_t pid)
 }
 
 Pid::~Pid()
-{
+try {
     if (pid != -1)
-        kill();
+        kill(/*allowInterrupts=*/false);
+} catch (...) {
+    ignoreExceptionInDestructor();
 }
 
 void Pid::operator=(pid_t pid)
@@ -59,7 +61,7 @@ Pid::operator pid_t()
     return pid;
 }
 
-int Pid::kill()
+int Pid::kill(bool allowInterrupts)
 {
     assert(pid != -1);
 
@@ -78,10 +80,10 @@ int Pid::kill()
             logError(SysError("killing process %d", pid).info());
     }
 
-    return wait();
+    return wait(allowInterrupts);
 }
 
-int Pid::wait()
+int Pid::wait(bool allowInterrupts)
 {
     assert(pid != -1);
     while (1) {
@@ -93,7 +95,8 @@ int Pid::wait()
         }
         if (errno != EINTR)
             throw SysError("cannot get exit status of PID %d", pid);
-        checkInterrupt();
+        if (allowInterrupts)
+            checkInterrupt();
     }
 }