Merge pull request #9798 from edolstra/remote-store-eof

Print a more helpful message if the daemon crashes

(cherry picked from commit 32706b14a7531c2c21b9f96da083a540a0031ec4)
Change-Id: Ief7c465bca7666e2b7e7c9d1dd0c01c5f9014146

2 files changed, 4 insertions, 3 deletions

diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 910a760a9..6b0d87b03 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -128,7 +128,7 @@ size_t FdSource::readUnbuffered(char * data, size_t len)
         n = ::read(fd, data, len);
     } while (n == -1 && errno == EINTR);
     if (n == -1) { _good = false; throw SysError("reading from file"); }
-    if (n == 0) { _good = false; throw EndOfFile("unexpected end-of-file"); }
+    if (n == 0) { _good = false; throw EndOfFile(std::string(*endOfFileError)); }
     read += n;
     return n;
 }
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 333c254ea..d1c791823 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -151,12 +151,13 @@ struct FdSource : BufferedSource
 {
     int fd;
     size_t read = 0;
+    BackedStringView endOfFileError{"unexpected end-of-file"};
 
     FdSource() : fd(-1) { }
     FdSource(int fd) : fd(fd) { }
-    FdSource(FdSource&&) = default;
+    FdSource(FdSource &&) = default;
 
-    FdSource& operator=(FdSource && s)
+    FdSource & operator=(FdSource && s)
     {
         fd = s.fd;
         s.fd = -1;