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merge-tree: fix d/f conflicts

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The previous commit documented two known breakages revolving around
a case where one side flips a tree into a blob (or vice versa),
where the original code simply gets confused and feeds a mixture of
trees and blobs into either the recursive merge-tree (and recursing
into the blob will fail) or three-way merge (and merging tree contents
together with blobs will fail).

Fix it by feeding trees (and only trees) into the recursive
merge-tree machinery and blobs (and only blobs) into the three-way
content level merge machinery separately; when this happens, the
entire merge has to be marked as conflicting at the structure level.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Junio C Hamano 2012-12-13 15:51:29 -08:00
parent 8dd15c6a90
commit 35ffe75831
2 changed files with 42 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

72
builtin/merge-tree.c
View file

@ -25,7 +25,7 @@ static void add_merge_entry(struct merge_list *entry)
merge_result_end = &entry->next;
}
static void merge_trees(struct tree_desc t[3], const char *base);
static void merge_trees_recursive(struct tree_desc t[3], const char *base, int df_conflict);
static const char *explanation(struct merge_list *entry)
{
@ -190,41 +190,35 @@ static void resolve(const struct traverse_info *info, struct name_entry *ours, s
add_merge_entry(final);
}
static int unresolved_directory(const struct traverse_info *info, struct name_entry n[3])
static void unresolved_directory(const struct traverse_info *info, struct name_entry n[3],
int df_conflict)
{
char *newbase;
struct name_entry *p;
struct tree_desc t[3];
void *buf0, *buf1, *buf2;
p = n;
if (!p->mode) {
p++;
if (!p->mode)
p++;
for (p = n; p < n + 3; p++) {
if (p->mode && S_ISDIR(p->mode))
break;
}
if (!S_ISDIR(p->mode))
return 0;
/*
* NEEDSWORK: this is broken. The path can originally be a file
* and then one side may have turned it into a directory, in which
* case we return and let the three-way merge as if the tree were
* a regular file. If the path that was originally a tree is
* now a file in either branch, fill_tree_descriptor() below will
* die when fed a blob sha1.
*/
if (n + 3 <= p)
return; /* there is no tree here */
newbase = traverse_path(info, p);
buf0 = fill_tree_descriptor(t+0, n[0].sha1);
buf1 = fill_tree_descriptor(t+1, n[1].sha1);
buf2 = fill_tree_descriptor(t+2, n[2].sha1);
merge_trees(t, newbase);
#define ENTRY_SHA1(e) (((e)->mode && S_ISDIR((e)->mode)) ? (e)->sha1 : NULL)
buf0 = fill_tree_descriptor(t+0, ENTRY_SHA1(n + 0));
buf1 = fill_tree_descriptor(t+1, ENTRY_SHA1(n + 1));
buf2 = fill_tree_descriptor(t+2, ENTRY_SHA1(n + 2));
#undef ENTRY_SHA1
merge_trees_recursive(t, newbase, df_conflict);
free(buf0);
free(buf1);
free(buf2);
free(newbase);
return 1;
}
@ -247,18 +241,26 @@ static struct merge_list *link_entry(unsigned stage, const struct traverse_info
static void unresolved(const struct traverse_info *info, struct name_entry n[3])
{
struct merge_list *entry = NULL;
int i;
unsigned dirmask = 0, mask = 0;
if (unresolved_directory(info, n))
for (i = 0; i < 3; i++) {
mask |= (1 << 1);
if (n[i].mode && S_ISDIR(n[i].mode))
dirmask |= (1 << i);
}
unresolved_directory(info, n, dirmask && (dirmask != mask));
if (dirmask == mask)
return;
/*
* Do them in reverse order so that the resulting link
* list has the stages in order - link_entry adds new
* links at the front.
*/
entry = link_entry(3, info, n + 2, entry);
entry = link_entry(2, info, n + 1, entry);
entry = link_entry(1, info, n + 0, entry);
if (n[2].mode && !S_ISDIR(n[2].mode))
entry = link_entry(3, info, n + 2, entry);
if (n[1].mode && !S_ISDIR(n[1].mode))
entry = link_entry(2, info, n + 1, entry);
if (n[0].mode && !S_ISDIR(n[0].mode))
entry = link_entry(1, info, n + 0, entry);
add_merge_entry(entry);
}
@ -329,15 +331,21 @@ static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, s
return mask;
}
static void merge_trees(struct tree_desc t[3], const char *base)
static void merge_trees_recursive(struct tree_desc t[3], const char *base, int df_conflict)
{
struct traverse_info info;
setup_traverse_info(&info, base);
info.data = &df_conflict;
info.fn = threeway_callback;
traverse_trees(3, t, &info);
}
static void merge_trees(struct tree_desc t[3], const char *base)
{
merge_trees_recursive(t, base, 0);
}
static void *get_tree_descriptor(struct tree_desc *desc, const char *rev)
{
unsigned char sha1[20];

4
t/t4300-merge-tree.sh
View file

@ -254,7 +254,7 @@ EXPECTED
test_cmp expected actual
'
test_expect_failure 'turn file to tree' '
test_expect_success 'turn file to tree' '
git reset --hard initial &&
rm initial-file &&
mkdir initial-file &&
@ -274,7 +274,7 @@ test_expect_failure 'turn file to tree' '
test_cmp expect actual
'
test_expect_failure 'turn tree to file' '
test_expect_success 'turn tree to file' '
git reset --hard initial &&
mkdir dir &&
test_commit "add-tree" "dir/path" "AAA" &&