Merge pull request #3655 from ethomson/nanosecond_defaults

Enable nanosecond resolution by default

CMakeLists.txt

@@ -109,7 +109,7 @@ ELSE ()
 ENDIF()
 
 IF (HAVE_STRUCT_STAT_NSEC OR WIN32)
-	OPTION( USE_NSEC		"Care about sub-second file mtimes and ctimes"	OFF )
+	OPTION( USE_NSEC		"Care about sub-second file mtimes and ctimes"	ON  )
 ENDIF()
 
 # This variable will contain the libraries we need to put into

tests/index/nsec.c

@@ -24,6 +24,43 @@ void test_index_nsec__cleanup(void)
 	cl_git_sandbox_cleanup();
 }
 
+static bool try_create_file_with_nsec_timestamp(const char *path)
+{
+	struct stat st;
+	int try;
+
+	/* retry a few times to avoid nanos *actually* equal 0 race condition */
+	for (try = 0; try < 3; try++) {
+		cl_git_mkfile(path, "This is hopefully a file with nanoseconds!");
+
+		cl_must_pass(p_stat(path, &st));
+
+		if (st.st_ctime_nsec && st.st_mtime_nsec)
+			return true;
+	}
+
+	return false;
+}
+
+/* try to determine if the underlying filesystem supports a resolution
+ * higher than a single second.  (i'm looking at you, hfs+)
+ */
+static bool should_expect_nsecs(void)
+{
+	git_buf nsec_path = GIT_BUF_INIT;
+	bool expect;
+
+	git_buf_joinpath(&nsec_path, clar_sandbox_path(), "nsec_test");
+
+	expect = try_create_file_with_nsec_timestamp(nsec_path.ptr);
+
+	p_unlink(nsec_path.ptr);
+
+	git_buf_clear(&nsec_path);
+
+	return expect;
+}
+
 static bool has_nsecs(void)
 {
 	const git_index_entry *entry;
@@ -50,8 +87,13 @@ void test_index_nsec__has_nanos(void)
 void test_index_nsec__staging_maintains_other_nanos(void)
 {
 	const git_index_entry *entry;
+	bool expect_nsec, test_file_has_nsec;
+
+    expect_nsec = should_expect_nsecs();
+	test_file_has_nsec = try_create_file_with_nsec_timestamp("nsecs/a.txt");
+
+	cl_assert_equal_b(expect_nsec, test_file_has_nsec);
 
-	cl_git_rewritefile("nsecs/a.txt", "This is file A");
 	cl_git_pass(git_index_add_bypath(repo_index, "a.txt"));
 	cl_git_pass(git_index_write(repo_index));
 
@@ -63,15 +105,15 @@ void test_index_nsec__staging_maintains_other_nanos(void)
 	cl_assert((entry = git_index_get_bypath(repo_index, "a.txt", 0)));
 
 	/* if we are writing nanoseconds to the index, expect them to be
-	 * nonzero.  if we are *not*, expect that we truncated the entry.
+	 * nonzero.
 	 */
-#ifdef GIT_USE_NSEC
+	if (expect_nsec) {
 		cl_assert(entry->ctime.nanoseconds != 0);
 		cl_assert(entry->mtime.nanoseconds != 0);
-#else
+	} else {
 		cl_assert_equal_i(0, entry->ctime.nanoseconds);
 		cl_assert_equal_i(0, entry->mtime.nanoseconds);
-#endif
+	}
 }
 
 void test_index_nsec__status_doesnt_clear_nsecs(void)

tests/index/racy.c

@@ -105,8 +105,8 @@ static void setup_race(void)
 {
 	git_buf path = GIT_BUF_INIT;
 	git_index *index;
-	const git_index_entry *entry;
-	int i, found_race = 0;
+	git_index_entry *entry;
+	struct stat st;
 
 	/* Make sure we do have a timestamp */
 	cl_git_pass(git_repository_index__weakptr(&index, g_repo));
@@ -114,27 +114,20 @@ static void setup_race(void)
 
 	cl_git_pass(git_buf_joinpath(&path, git_repository_workdir(g_repo), "A"));
 
-	/* Make sure writing the file, adding and rewriting happen in the same second */
-	for (i = 0; i < 10; i++) {
-		struct stat st;
 	cl_git_mkfile(path.ptr, "A");
-
 	cl_git_pass(git_index_add_bypath(index, "A"));
+
 	cl_git_mkfile(path.ptr, "B");
 	cl_git_pass(git_index_write(index));
 
 	cl_git_mkfile(path.ptr, "");
 
 	cl_git_pass(p_stat(path.ptr, &st));
-		cl_assert(entry = git_index_get_bypath(index, "A", 0));
-		if (entry->mtime.seconds == (int32_t) st.st_mtime) {
-			found_race = 1;
-			break;
-		}
-	}
-
-	if (!found_race)
-		cl_fail("failed to find race after 10 attempts");
+	cl_assert(entry = (git_index_entry *)git_index_get_bypath(index, "A", 0));
+
+	/* force a race */
+	entry->mtime.seconds = st.st_mtime;
+	entry->mtime.nanoseconds = st.st_mtime_nsec;
 
 	git_buf_free(&path);
 }

tests/merge/workdir/dirty.c

@@ -165,8 +165,8 @@ static void hack_index(char *files[])
 		entry->ctime.seconds = (int32_t)statbuf.st_ctime;
 		entry->mtime.seconds = (int32_t)statbuf.st_mtime;
 #if defined(GIT_USE_NSEC)
-		entry->ctime.nanoseconds = statbuf.st_ctim.tv_nsec;
-		entry->mtime.nanoseconds = statbuf.st_mtim.tv_nsec;
+		entry->ctime.nanoseconds = statbuf.st_ctime_nsec;
+		entry->mtime.nanoseconds = statbuf.st_mtime_nsec;
 #else
 		entry->ctime.nanoseconds = 0;
 		entry->mtime.nanoseconds = 0;