[v3,1/3] diff-files --raw: handle intent-to-add files correctly

Commit Message

John Passaro via GitGitGadget June 24, 2020, 2:47 p.m. UTC

From: Johannes Schindelin <[e-mail]>

In `run_diff_files()`, files that have been staged with the intention to
add are queued without a valid OID in the `diff_filepair`.

When the output mode is, say, `DIFF_FORMAT_PATCH`, the
`diff_fill_oid_info()` function, called from `run_diff()`, will remedy
that situation by reading the file contents from disk.

However, when the output mode is `DIFF_FORMAT_RAW`, that does not hold
true, and the output will contain a bogus OID (and the flag `M` for
"modified" instead of the correct `A` for "added").

As a consequence, `git difftool -d` (which relies on `git diff-files
--raw`'s output) does not work correctly.

Let's fix this specifically by imitating `diff_fill_oid_info()`.

Note: we can only do that for diff formats that do not actually need the
file contents, such as `DIFF_FORMAT_PATCH`: `run_diff()` would try to
read the blob contents, but that blob might not have been written to
Git's object database.

This fixes https://github.com/git-for-windows/git/issues/2677

This patch _also_ fixes the expectations set by the regression test
introduced in feea6946a5b (diff-files: treat "i-t-a" files as
"not-in-index", 2020-06-20).

Signed-off-by: Johannes Schindelin <[e-mail]>
---
 diff-lib.c             | 14 ++++++++++++++
 t/t2203-add-intent.sh  |  5 ++---
 t/t4000-diff-format.sh | 10 ++++++++++
 3 files changed, 26 insertions(+), 3 deletions(-)

Patch

diff --git a/diff-lib.c b/diff-lib.c
index 61812f48c2..ea23169afa 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -217,6 +217,20 @@  int run_diff_files(struct rev_info *revs, unsigned int option)
 					       !is_null_oid(&ce->oid),
 					       ce->name, 0);
 				continue;
+			} else if (ce_intent_to_add(ce) &&
+				   !(revs->diffopt.output_format &
+				     ~(DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))) {
+				struct object_id oid;
+				int ret = lstat(ce->name, &st);
+
+				if (ret < 0)
+					oidclr(&oid);
+				else
+					ret = index_path(istate, &oid,
+						 ce->name, &st, 0);
+				diff_addremove(&revs->diffopt, '+', ce->ce_mode,
+					       &oid, ret >= 0, ce->name, 0);
+				continue;
 			} else if (revs->diffopt.ita_invisible_in_index &&
 				   ce_intent_to_add(ce)) {
 				diff_addremove(&revs->diffopt, '+', ce->ce_mode,
diff --git a/t/t2203-add-intent.sh b/t/t2203-add-intent.sh
index 8a5d55054f..7d379bdbc6 100755
--- a/t/t2203-add-intent.sh
+++ b/t/t2203-add-intent.sh
@@ -240,7 +240,6 @@  test_expect_success 'i-t-a files shown as new for "diff", "diff-files"; not-new
 
 	hash_e=$(git hash-object empty) &&
 	hash_n=$(git hash-object not-empty) &&
-	hash_t=$(git hash-object -t tree /dev/null) &&
 
 	cat >expect.diff_p <<-EOF &&
 	diff --git a/empty b/empty
@@ -259,8 +258,8 @@  test_expect_success 'i-t-a files shown as new for "diff", "diff-files"; not-new
 	 create mode 100644 not-empty
 	EOF
 	cat >expect.diff_a <<-EOF &&
-	:000000 100644 0000000 $(git rev-parse --short $hash_t) A$(printf "\t")empty
-	:000000 100644 0000000 $(git rev-parse --short $hash_t) A$(printf "\t")not-empty
+	:000000 100644 0000000 $(git rev-parse --short $hash_e) A$(printf "\t")empty
+	:000000 100644 0000000 $(git rev-parse --short $hash_n) A$(printf "\t")not-empty
 	EOF
 
 	git add -N empty not-empty &&
diff --git a/t/t4000-diff-format.sh b/t/t4000-diff-format.sh
index e5116a76a1..48ff4e250b 100755
--- a/t/t4000-diff-format.sh
+++ b/t/t4000-diff-format.sh
@@ -89,4 +89,14 @@  test_expect_success 'git diff-files --patch --no-patch does not show the patch'
 	test_must_be_empty err
 '
 
+test_expect_success 'git diff-files --raw handles intent-to-add files correctly' '
+	echo 123 >ita &&
+	git add -N ita &&
+	printf ":000000 100644 %s %s A\\tita\n" \
+		$ZERO_OID $(git hash-object --stdin <ita) >expect &&
+	git diff-files --raw ita >actual &&
+	test_cmp expect actual
+'
+
+
 test_done