From: Daniel Colascione <dancol@dancol.org>
Date: Mon, 26 Feb 2018 06:22:40 +0000 (-0800)
Subject: Improve error message when attempting to load failed dump file
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=aacc1390f21ddb003c9d6a786597e89284bafec3;p=emacs.git

Improve error message when attempting to load failed dump file
---

diff --git a/src/emacs.c b/src/emacs.c
index 415981096c3..0ed3f905bbe 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -714,6 +714,8 @@ dump_error_to_string (enum pdumper_load_result result)
       return "could not open file";
     case PDUMPER_LOAD_BAD_FILE_TYPE:
       return "not a dump file";
+    case PDUMPER_LOAD_FAILED_DUMP:
+      return "dump file is result of failed dump attempt";
     case PDUMPER_LOAD_VERSION_MISMATCH:
       return "not built for this Emacs executable";
     default:
diff --git a/src/pdumper.c b/src/pdumper.c
index 80ed9a8183f..400177223a4 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -5145,9 +5145,18 @@ pdumper_load (const char *dump_filename)
                      sizeof (*header)) < sizeof (*header))
     goto out;
 
-  err = PDUMPER_LOAD_BAD_FILE_TYPE;
   if (memcmp (header->magic, dump_magic, sizeof (dump_magic)) != 0)
-    goto out;
+    {
+      if (header->magic[0] == '!' &&
+          ((header->magic[0] = dump_magic[0]),
+           memcmp (header->magic, dump_magic, sizeof (dump_magic)) == 0))
+        {
+          err = PDUMPER_LOAD_FAILED_DUMP;
+          goto out;
+        }
+      err = PDUMPER_LOAD_BAD_FILE_TYPE;
+      goto out;
+    }
 
   err = PDUMPER_LOAD_VERSION_MISMATCH;
   verify (sizeof (header->fingerprint) == sizeof (fingerprint));
diff --git a/src/pdumper.h b/src/pdumper.h
index c40761944d8..48d34dc0bf1 100644
--- a/src/pdumper.h
+++ b/src/pdumper.h
@@ -125,6 +125,7 @@ enum pdumper_load_result
     PDUMPER_NOT_LOADED /* Not returned: useful for callers */,
     PDUMPER_LOAD_FILE_NOT_FOUND,
     PDUMPER_LOAD_BAD_FILE_TYPE,
+    PDUMPER_LOAD_FAILED_DUMP,
     PDUMPER_LOAD_OOM,
     PDUMPER_LOAD_VERSION_MISMATCH,
     PDUMPER_LOAD_ERROR,