The documentation mentions "git-diff --cached" to see what is staged for
the next commit. But this failes if you haven't done any commits yet.
So lets fix it.
Signed-off-by: Peter Baumann <siprbaum@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
---
I was bitten by this during explaining a total git newbie the index and
the several ways to diff index <-> wd, index <-> commit, commit <-> commit.
I posted this example
mkdir testrepo && cd testrepo
git init
echo foo > test.txt
git add test.txt
git diff --cached
usage: git-diff <options> <rev>{0,2} -- <path>*
and was totaly shocked to see the above error message.
I am not sure if this is the right fix and/or if git-diff-index
should also be fixed. I decided against it and let the core cmd git-diff-index
stay as it is now.
builtin-diff.c | 22 +++++++++++++++++++---
t/t4017-diff-cached.sh | 21 +++++++++++++++++++++
2 files changed, 40 insertions(+), 3 deletions(-)
create mode 100755 t/t4017-diff-cached.sh
diff --git a/builtin-diff.c b/builtin-diff.c
index c387ebb..aace507 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -203,11 +203,27 @@ void add_head(struct rev_info *revs)
{
unsigned char sha1[20];
struct object *obj;
- if (get_sha1("HEAD", sha1))
+ int ret = get_sha1("HEAD", sha1);
+ if (ret > 0)
return;
- obj = parse_object(sha1);
- if (!obj)
+
+ if (ret == 0)
+ obj = parse_object(sha1);
+ else {
+ /* HEAD exists but the branch it points to does not;
+ * we haven't done any commit yet => create an empty tree
+ * to make git diff --cached work
+ */
+ obj = xcalloc(1, sizeof(struct object));
+ obj->parsed = 1;
+ obj->type = OBJ_TREE;
+
+ pretend_sha1_file(NULL, 0, tree_type, obj->sha1);
+ }
+
+ if (!obj) {
return;
+ }
add_pending_object(revs, obj, "HEAD");
}
diff --git a/t/t4017-diff-cached.sh b/t/t4017-diff-cached.sh
new file mode 100755
index 0000000..39fc32f
--- /dev/null
+++ b/t/t4017-diff-cached.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Copyright (c) 2007 Peter Baumann
+#
+
+test_description='Test diff --cached without inital commit.
+
+'
+. ./test-lib.sh
+
+test_expect_success \
+ 'setup' \
+ 'echo frotz >rezrov &&
+ git-update-index --add rezrov'
+
+test_expect_success \
+ 'git-diff --cached' \
+ 'git-diff --cached'
+
+test_done
+
--
1.5.0.1.213.g509b-dirty
-
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