Rename core.unreliableHardlinks to core.createObject

"Unreliable hardlinks" is a misleading description for what is happening.
So rename it to something less misleading.

Suggested by Linus Torvalds.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

6 files changed, 30 insertions, 16 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index d31adb671..5dcad94f8 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -429,10 +429,14 @@ relatively high IO latencies.  With this set to 'true', git will do the
 index comparison to the filesystem data in parallel, allowing
 overlapping IO's.
 
-core.unreliableHardlinks::
-	Some filesystem drivers cannot properly handle hardlinking a file
-	and deleting the source right away.  In such a case, you need to
-	set this config variable to 'true'.
+core.createObject::
+	You can set this to 'link', in which case a hardlink followed by
+	a delete of the source are used to make sure that object creation
+	will not overwrite existing objects.
++
+On some file system/operating system combinations, this is unreliable.
+Set this config setting to 'rename' there; However, This will remove the
+check that makes sure that existing object files will not get overwritten.
 
 alias.*::
 	Command aliases for the linkgit:git[1] command wrapper - e.g.
diff --git a/Makefile b/Makefile
index 6b80f81d6..6e216436c 100644
--- a/Makefile
+++ b/Makefile
@@ -172,8 +172,8 @@ all::
 # information on a not yet closed file that lstat would return for the same
 # file after it was closed.
 #
-# Define UNRELIABLE_HARDLINKS if your operating systems has problems when
-# hardlinking a file to another name and unlinking the original file right
+# Define OBJECT_CREATION_USES_RENAMES if your operating systems has problems
+# when hardlinking a file to another name and unlinking the original file right
 # away (some NTFS drivers seem to zero the contents in that scenario).
 
 GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
@@ -837,7 +837,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_NSEC = YesPlease
 	USE_WIN32_MMAP = YesPlease
 	UNRELIABLE_FSTAT = UnfortunatelyYes
-	UNRELIABLE_HARDLINKS = UnfortunatelySometimes
+	OBJECT_CREATION_USES_RENAMES = UnfortunatelyNeedsTo
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/regex -Icompat/fnmatch
 	COMPAT_CFLAGS += -DSNPRINTF_SIZE_CORR=1
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
@@ -1021,8 +1021,8 @@ else
 		COMPAT_OBJS += compat/win32mmap.o
 	endif
 endif
-ifdef UNRELIABLE_HARDLINKS
-	COMPAT_CFLAGS += -DUNRELIABLE_HARDLINKS=1
+ifdef OBJECT_CREATION_USES_RENAMES
+	COMPAT_CFLAGS += -DOBJECT_CREATION_MODE=1
 endif
 ifdef NO_PREAD
 	COMPAT_CFLAGS += -DNO_PREAD
diff --git a/cache.h b/cache.h
index ff9e145be..d0d48b4c8 100644
--- a/cache.h
+++ b/cache.h
@@ -554,7 +554,12 @@ extern enum branch_track git_branch_track;
 extern enum rebase_setup_type autorebase;
 extern enum push_default_type push_default;
 
-extern int unreliable_hardlinks;
+enum object_creation_mode {
+	OBJECT_CREATION_USES_HARDLINKS = 0,
+	OBJECT_CREATION_USES_RENAMES = 1,
+};
+
+extern enum object_creation_mode object_creation_mode;
 
 #define GIT_REPO_VERSION 0
 extern int repository_format_version;
diff --git a/config.c b/config.c
index 1750cfb85..563a91594 100644
--- a/config.c
+++ b/config.c
@@ -495,8 +495,13 @@ static int git_default_core_config(const char *var, const char *value)
 		return 0;
 	}
 
-	if (!strcmp(var, "core.unreliablehardlinks")) {
-		unreliable_hardlinks = git_config_bool(var, value);
+	if (!strcmp(var, "core.createobject")) {
+		if (!strcmp(value, "rename"))
+			object_creation_mode = OBJECT_CREATION_USES_RENAMES;
+		else if (!strcmp(value, "link"))
+			object_creation_mode = OBJECT_CREATION_USES_HARDLINKS;
+		else
+			die("Invalid mode for object creation: %s", value);
 		return 0;
 	}
 
diff --git a/environment.c b/environment.c
index 10578d24d..801a005ef 100644
--- a/environment.c
+++ b/environment.c
@@ -43,10 +43,10 @@ unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
 enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
 enum rebase_setup_type autorebase = AUTOREBASE_NEVER;
 enum push_default_type push_default = PUSH_DEFAULT_UNSPECIFIED;
-#ifndef UNRELIABLE_HARDLINKS
-#define UNRELIABLE_HARDLINKS 0
+#ifndef OBJECT_CREATION_MODE
+#define OBJECT_CREATION_MODE OBJECT_CREATION_USES_HARDLINKS
 #endif
-int unreliable_hardlinks = UNRELIABLE_HARDLINKS;
+enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 
 /* Parallel index stat data preload? */
 int core_preload_index = 0;
diff --git a/sha1_file.c b/sha1_file.c
index 11969fc16..f708cf4f6 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2225,7 +2225,7 @@ int move_temp_to_file(const char *tmpfile, const char *filename)
 {
 	int ret = 0;
 
-	if (unreliable_hardlinks)
+	if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
 		goto try_rename;
 	else if (link(tmpfile, filename))
 		ret = errno;