Subject: Re: [PATCH v2] diff-lib.c: adjust position of i-t-a entries in diff

From: Michael J Gruber <[email-masked]>
Date: Mon, 16 Mar 2015 16:15:53 +0100

Nguyễn Thái Ngọc Duy venit, vidit, dixit 16.03.2015 14:56:
> Entries added by "git add -N" are reminder for the user so that they
> don't forget to add them before committing. These entries appear in
> the index even though they are not real. Their presence in the index
> leads to a confusing "git status" like this:
> 
>     On branch master
>     Changes to be committed:
>             new file:   foo
> 
>     Changes not staged for commit:
>             modified:   foo
> 
> If you do a "git commit", "foo" will not be included even though
> "status" reports it as "to be committed". This patch changes the
> output to become
> 
>     On branch master
>     Changes not staged for commit:
>             new file:   foo
> 
>     no changes added to commit
> 
> The two hunks in diff-lib.c adjust "diff-index" and "diff-files" so
> that i-t-a entries appear as new files in diff-files and nothing in
> diff-index.
> 
> Due to this change, diff-files may start to report "new files" for the
> first time. "add -u" needs to be told about this or it will die in
> denial, screaming "new files can't exist! Reality is wrong." Luckily,
> it's the only one among run_diff_files() callers that needs fixing.
> 
> The test "cache-tree invalidates i-t-a paths" is marked failure
> because I don't think removing "--cached" from "git diff" is the right
> fix. This test relies on "diff --cached" behavior but the behavior now
> has changed. We may need to revisit this test at some point in future.

I can't quite follow that reasoning. If the test describes expected
behavior which the patch breaks, then we should not apply the patch. If
the patch changes behavior in an expected way, then we should change the
test to match.

> Helped-by: Michael J Gruber <[email-masked]>
> Helped-by: Junio C Hamano <[email-masked]>
> Signed-off-by: Nguyễn Thái Ngọc Duy <[email-masked]>
> ---
>  builtin/add.c           |  1 +
>  diff-lib.c              | 12 ++++++++++++
>  t/t2203-add-intent.sh   | 21 ++++++++++++++++++---
>  t/t4011-diff-symlink.sh | 10 ++++++----
>  4 files changed, 37 insertions(+), 7 deletions(-)
> 
> diff --git a/builtin/add.c b/builtin/add.c
> index 3390933..ee370b0 100644
> --- a/builtin/add.c
> +++ b/builtin/add.c
> @@ -63,6 +63,7 @@ static void update_callback(struct diff_queue_struct *q,
>  		switch (fix_unmerged_status(p, data)) {
>  		default:
>  			die(_("unexpected diff status %c"), p->status);
> +		case DIFF_STATUS_ADDED:
>  		case DIFF_STATUS_MODIFIED:
>  		case DIFF_STATUS_TYPE_CHANGED:
>  			if (add_file_to_index(&the_index, path, data->flags)) {
> diff --git a/diff-lib.c b/diff-lib.c
> index a85c497..714501a 100644
> --- a/diff-lib.c
> +++ b/diff-lib.c
> @@ -212,6 +212,11 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
>  					       ce->sha1, !is_null_sha1(ce->sha1),
>  					       ce->name, 0);
>  				continue;
> +			} else if (ce->ce_flags & CE_INTENT_TO_ADD) {
> +				diff_addremove(&revs->diffopt, '+', ce->ce_mode,
> +					       EMPTY_BLOB_SHA1_BIN, 0,
> +					       ce->name, 0);
> +				continue;
>  			}
>  
>  			changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
> @@ -376,6 +381,13 @@ static void do_oneway_diff(struct unpack_trees_options *o,
>  	struct rev_info *revs = o->unpack_data;
>  	int match_missing, cached;
>  
> +	/* i-t-a entries do not actually exist in the index */
> +	if (idx && (idx->ce_flags & CE_INTENT_TO_ADD)) {
> +		idx = NULL;
> +		if (!tree)
> +			return;	/* nothing to diff.. */
> +	}
> +
>  	/* if the entry is not checked out, don't examine work tree */
>  	cached = o->index_only ||
>  		(idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
> diff --git a/t/t2203-add-intent.sh b/t/t2203-add-intent.sh
> index 2a4a749..42827b8 100755
> --- a/t/t2203-add-intent.sh
> +++ b/t/t2203-add-intent.sh
> @@ -5,10 +5,24 @@ test_description='Intent to add'
>  . ./test-lib.sh
>  
>  test_expect_success 'intent to add' '
> +	test_commit 1 &&
> +	git rm 1.t &&
> +	echo hello >1.t &&
>  	echo hello >file &&
>  	echo hello >elif &&
>  	git add -N file &&
> -	git add elif
> +	git add elif &&
> +	git add -N 1.t
> +'
> +
> +test_expect_success 'git status' '
> +	git status --porcelain | grep -v actual >actual &&
> +	cat >expect <<-\EOF &&
> +	DA 1.t
> +	A  elif
> +	 A file
> +	EOF
> +	test_cmp expect actual
>  '
>  
>  test_expect_success 'check result of "add -N"' '
> @@ -43,7 +57,8 @@ test_expect_success 'i-t-a entry is simply ignored' '
>  	git add -N nitfol &&
>  	git commit -m second &&
>  	test $(git ls-tree HEAD -- nitfol | wc -l) = 0 &&
> -	test $(git diff --name-only HEAD -- nitfol | wc -l) = 1
> +	test $(git diff --name-only HEAD -- nitfol | wc -l) = 0 &&
> +	test $(git diff --name-only -- nitfol | wc -l) = 1
>  '
>  
>  test_expect_success 'can commit with an unrelated i-t-a entry in index' '
> @@ -62,7 +77,7 @@ test_expect_success 'can "commit -a" with an i-t-a entry' '
>  	git commit -a -m all
>  '
>  
> -test_expect_success 'cache-tree invalidates i-t-a paths' '
> +test_expect_failure 'cache-tree invalidates i-t-a paths' '
>  	git reset --hard &&
>  	mkdir dir &&
>  	: >dir/foo &&
> diff --git a/t/t4011-diff-symlink.sh b/t/t4011-diff-symlink.sh
> index 13e7f62..7452fce 100755
> --- a/t/t4011-diff-symlink.sh
> +++ b/t/t4011-diff-symlink.sh
> @@ -139,11 +139,13 @@ test_expect_success SYMLINKS 'setup symlinks with attributes' '
>  test_expect_success SYMLINKS 'symlinks do not respect userdiff config by path' '
>  	cat >expect <<-\EOF &&
>  	diff --git a/file.bin b/file.bin
> -	index e69de29..d95f3ad 100644
> -	Binary files a/file.bin and b/file.bin differ
> +	new file mode 100644
> +	index 0000000..d95f3ad
> +	Binary files /dev/null and b/file.bin differ
>  	diff --git a/link.bin b/link.bin
> -	index e69de29..dce41ec 120000
> -	--- a/link.bin
> +	new file mode 120000
> +	index 0000000..dce41ec
> +	--- /dev/null
>  	+++ b/link.bin
>  	@@ -0,0 +1 @@
>  	+file.bin
>