[PATCH] Rewrite read-tree
Adds support for multiple ancestors, removes --emu23, much simplification.
Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/read-tree.c b/read-tree.c
index ce2bb88..0241c9c 100644
--- a/read-tree.c
+++ b/read-tree.c
@@ -5,431 +5,225 @@
*/
#include "cache.h"
-static int stage = 0;
+#include "object.h"
+#include "tree.h"
+
+static int merge = 0;
static int update = 0;
-static int unpack_tree(unsigned char *sha1)
-{
- void *buffer;
- unsigned long size;
- int ret;
+static int head_idx = -1;
+static int merge_size = 0;
- buffer = read_object_with_reference(sha1, "tree", &size, NULL);
- if (!buffer)
- return -1;
- ret = read_tree(buffer, size, stage, NULL);
- free(buffer);
+static struct object_list *trees = NULL;
+
+static struct cache_entry df_conflict_entry = {
+};
+
+static struct tree_entry_list df_conflict_list = {
+ .name = NULL,
+ .next = &df_conflict_list
+};
+
+typedef int (*merge_fn_t)(struct cache_entry **src);
+
+static int entcmp(char *name1, int dir1, char *name2, int dir2)
+{
+ int len1 = strlen(name1);
+ int len2 = strlen(name2);
+ int len = len1 < len2 ? len1 : len2;
+ int ret = memcmp(name1, name2, len);
+ unsigned char c1, c2;
+ if (ret)
+ return ret;
+ c1 = name1[len];
+ c2 = name2[len];
+ if (!c1 && dir1)
+ c1 = '/';
+ if (!c2 && dir2)
+ c2 = '/';
+ ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
+ if (c1 && c2 && !ret)
+ ret = len1 - len2;
return ret;
}
-static int path_matches(struct cache_entry *a, struct cache_entry *b)
+static int unpack_trees_rec(struct tree_entry_list **posns, int len,
+ const char *base, merge_fn_t fn, int *indpos)
{
- int len = ce_namelen(a);
- return ce_namelen(b) == len &&
- !memcmp(a->name, b->name, len);
+ int baselen = strlen(base);
+ int src_size = len + 1;
+ do {
+ int i;
+ char *first;
+ int firstdir = 0;
+ int pathlen;
+ unsigned ce_size;
+ struct tree_entry_list **subposns;
+ struct cache_entry **src;
+ int any_files = 0;
+ int any_dirs = 0;
+ char *cache_name;
+ int ce_stage;
+
+ /* Find the first name in the input. */
+
+ first = NULL;
+ cache_name = NULL;
+
+ /* Check the cache */
+ if (merge && *indpos < active_nr) {
+ /* This is a bit tricky: */
+ /* If the index has a subdirectory (with
+ * contents) as the first name, it'll get a
+ * filename like "foo/bar". But that's after
+ * "foo", so the entry in trees will get
+ * handled first, at which point we'll go into
+ * "foo", and deal with "bar" from the index,
+ * because the base will be "foo/". The only
+ * way we can actually have "foo/bar" first of
+ * all the things is if the trees don't
+ * contain "foo" at all, in which case we'll
+ * handle "foo/bar" without going into the
+ * directory, but that's fine (and will return
+ * an error anyway, with the added unknown
+ * file case.
+ */
+
+ cache_name = active_cache[*indpos]->name;
+ if (strlen(cache_name) > baselen &&
+ !memcmp(cache_name, base, baselen)) {
+ cache_name += baselen;
+ first = cache_name;
+ } else {
+ cache_name = NULL;
+ }
+ }
+
+ if (first)
+ printf("index %s\n", first);
+
+ for (i = 0; i < len; i++) {
+ if (!posns[i] || posns[i] == &df_conflict_list)
+ continue;
+ printf("%d %s\n", i + 1, posns[i]->name);
+ if (!first || entcmp(first, firstdir,
+ posns[i]->name,
+ posns[i]->directory) > 0) {
+ first = posns[i]->name;
+ firstdir = posns[i]->directory;
+ }
+ }
+ /* No name means we're done */
+ if (!first)
+ return 0;
+
+ pathlen = strlen(first);
+ ce_size = cache_entry_size(baselen + pathlen);
+
+ src = xmalloc(sizeof(struct cache_entry *) * src_size);
+ memset(src, 0, sizeof(struct cache_entry *) * src_size);
+
+ subposns = xmalloc(sizeof(struct tree_list_entry *) * len);
+ memset(subposns, 0, sizeof(struct tree_list_entry *) * len);
+
+ if (cache_name && !strcmp(cache_name, first)) {
+ any_files = 1;
+ src[0] = active_cache[*indpos];
+ remove_cache_entry_at(*indpos);
+ }
+
+ for (i = 0; i < len; i++) {
+ struct cache_entry *ce;
+
+ if (!posns[i] ||
+ (posns[i] != &df_conflict_list &&
+ strcmp(first, posns[i]->name))) {
+ continue;
+ }
+
+ if (posns[i] == &df_conflict_list) {
+ src[i + merge] = &df_conflict_entry;
+ continue;
+ }
+
+ if (posns[i]->directory) {
+ any_dirs = 1;
+ parse_tree(posns[i]->item.tree);
+ subposns[i] = posns[i]->item.tree->entries;
+ posns[i] = posns[i]->next;
+ src[i + merge] = &df_conflict_entry;
+ continue;
+ }
+
+ if (!merge)
+ ce_stage = 0;
+ else if (i + 1 < head_idx)
+ ce_stage = 1;
+ else if (i + 1 > head_idx)
+ ce_stage = 3;
+ else
+ ce_stage = 2;
+
+ ce = xmalloc(ce_size);
+ memset(ce, 0, ce_size);
+ ce->ce_mode = create_ce_mode(posns[i]->mode);
+ ce->ce_flags = create_ce_flags(baselen + pathlen,
+ ce_stage);
+ memcpy(ce->name, base, baselen);
+ memcpy(ce->name + baselen, first, pathlen + 1);
+
+ any_files = 1;
+
+ memcpy(ce->sha1, posns[i]->item.any->sha1, 20);
+ src[i + merge] = ce;
+ subposns[i] = &df_conflict_list;
+ posns[i] = posns[i]->next;
+ }
+ if (any_files) {
+ if (merge) {
+ int ret;
+
+ printf("%s:\n", first);
+ for (i = 0; i < src_size; i++) {
+ printf(" %d ", i);
+ if (src[i])
+ printf("%s\n", sha1_to_hex(src[i]->sha1));
+ else
+ printf("\n");
+ }
+
+ ret = fn(src);
+
+ printf("Added %d entries\n", ret);
+
+ *indpos += ret;
+ } else {
+ for (i = 0; i < src_size; i++) {
+ if (src[i]) {
+ add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
+ }
+ }
+ }
+ }
+ if (any_dirs) {
+ char *newbase = xmalloc(baselen + 2 + pathlen);
+ memcpy(newbase, base, baselen);
+ memcpy(newbase + baselen, first, pathlen);
+ newbase[baselen + pathlen] = '/';
+ newbase[baselen + pathlen + 1] = '\0';
+ if (unpack_trees_rec(subposns, len, newbase, fn,
+ indpos))
+ return -1;
+ }
+ free(subposns);
+ free(src);
+ } while (1);
}
-static int same(struct cache_entry *a, struct cache_entry *b)
-{
- return a->ce_mode == b->ce_mode &&
- !memcmp(a->sha1, b->sha1, 20);
-}
-
-
-/*
- * This removes all trivial merges that don't change the tree
- * and collapses them to state 0.
- */
-static struct cache_entry *merge_entries(struct cache_entry *a,
- struct cache_entry *b,
- struct cache_entry *c)
-{
- /*
- * Ok, all three entries describe the same
- * filename, but maybe the contents or file
- * mode have changed?
- *
- * The trivial cases end up being the ones where two
- * out of three files are the same:
- * - both destinations the same, trivially take either
- * - one of the destination versions hasn't changed,
- * take the other.
- *
- * The "all entries exactly the same" case falls out as
- * a special case of any of the "two same" cases.
- *
- * Here "a" is "original", and "b" and "c" are the two
- * trees we are merging.
- */
- if (a && b && c) {
- if (same(b,c))
- return c;
- if (same(a,b))
- return c;
- if (same(a,c))
- return b;
- }
- return NULL;
-}
-
-/*
- * When a CE gets turned into an unmerged entry, we
- * want it to be up-to-date
- */
-static void verify_uptodate(struct cache_entry *ce)
-{
- struct stat st;
-
- if (!lstat(ce->name, &st)) {
- unsigned changed = ce_match_stat(ce, &st);
- if (!changed)
- return;
- errno = 0;
- }
- if (errno == ENOENT)
- return;
- die("Entry '%s' not uptodate. Cannot merge.", ce->name);
-}
-
-/*
- * If the old tree contained a CE that isn't even in the
- * result, that's always a problem, regardless of whether
- * it's up-to-date or not (ie it can be a file that we
- * have updated but not committed yet).
- */
static void reject_merge(struct cache_entry *ce)
{
- die("Entry '%s' would be overwritten by merge. Cannot merge.", ce->name);
-}
-
-static int merged_entry_internal(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst, int allow_dirty)
-{
- merge->ce_flags |= htons(CE_UPDATE);
- if (old) {
- /*
- * See if we can re-use the old CE directly?
- * That way we get the uptodate stat info.
- *
- * This also removes the UPDATE flag on
- * a match.
- */
- if (same(old, merge)) {
- *merge = *old;
- } else if (!allow_dirty) {
- verify_uptodate(old);
- }
- }
- merge->ce_flags &= ~htons(CE_STAGEMASK);
- *dst++ = merge;
- return 1;
-}
-
-static int merged_entry_allow_dirty(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
-{
- return merged_entry_internal(merge, old, dst, 1);
-}
-
-static int merged_entry(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
-{
- return merged_entry_internal(merge, old, dst, 0);
-}
-
-static int deleted_entry(struct cache_entry *ce, struct cache_entry *old, struct cache_entry **dst)
-{
- if (old)
- verify_uptodate(old);
- ce->ce_mode = 0;
- *dst++ = ce;
- return 1;
-}
-
-static int causes_df_conflict(struct cache_entry *ce, int stage,
- struct cache_entry **dst_,
- struct cache_entry **next_,
- int tail)
-{
- /* This is called during the merge operation and walking
- * the active_cache[] array is messy, because it is in the
- * middle of overlapping copy operation. The invariants
- * are:
- * (1) active_cache points at the first (zeroth) entry.
- * (2) up to dst pointer are resolved entries.
- * (3) from the next pointer (head-inclusive) to the tail
- * of the active_cache array have the remaining paths
- * to be processed. There can be a gap between dst
- * and next. Note that next is called "src" in the
- * merge_cache() function, and tail is the original
- * end of active_cache array when merge_cache() started.
- * (4) the path corresponding to *ce is not found in (2)
- * or (3). It is in the gap.
- *
- * active_cache -----......+++++++++++++.
- * ^dst ^next ^tail
- */
- int i, next, dst;
- const char *path = ce->name;
- int namelen = ce_namelen(ce);
-
- next = next_ - active_cache;
- dst = dst_ - active_cache;
-
- for (i = 0; i < tail; i++) {
- int entlen, len;
- const char *one, *two;
- if (dst <= i && i < next)
- continue;
- ce = active_cache[i];
- if (ce_stage(ce) != stage)
- continue;
- /* If ce->name is a prefix of path, then path is a file
- * that hangs underneath ce->name, which is bad.
- * If path is a prefix of ce->name, then it is the
- * other way around which also is bad.
- */
- entlen = ce_namelen(ce);
- if (namelen == entlen)
- continue;
- if (namelen < entlen) {
- len = namelen;
- one = path;
- two = ce->name;
- } else {
- len = entlen;
- one = ce->name;
- two = path;
- }
- if (memcmp(one, two, len))
- continue;
- if (two[len] == '/')
- return 1;
- }
- return 0;
-}
-
-static int threeway_merge(struct cache_entry *stages[4],
- struct cache_entry **dst,
- struct cache_entry **next, int tail)
-{
- struct cache_entry *old = stages[0];
- struct cache_entry *a = stages[1], *b = stages[2], *c = stages[3];
- struct cache_entry *merge;
- int count;
-
- /* #5ALT */
- if (!a && b && c && same(b, c)) {
- if (old && !same(b, old))
- return -1;
- return merged_entry_allow_dirty(b, old, dst);
- }
- /* #2ALT and #3ALT */
- if (!a && (!!b != !!c)) {
- /*
- * The reason we need to worry about directory/file
- * conflicts only in #2ALT and #3ALT case is this:
- *
- * (1) For all other cases that read-tree internally
- * resolves a path, we always have such a path in
- * *both* stage2 and stage3 when we begin.
- * Traditionally, the behaviour has been even
- * stricter and we did not resolve a path without
- * initially being in all of stage1, 2, and 3.
- *
- * (2) When read-tree finishes, all resolved paths (i.e.
- * the paths that are in stage0) must have come from
- * either stage2 or stage3. It is not possible to
- * have a stage0 path as a result of a merge if
- * neither stage2 nor stage3 had that path.
- *
- * (3) It is guaranteed that just after reading the
- * stages, each stage cannot have directory/file
- * conflicts on its own, because they are populated
- * by reading hierarchy of a tree. Combined with
- * (1) and (2) above, this means that no matter what
- * combination of paths we take from stage2 and
- * stage3 as a result of a merge, they cannot cause
- * a directory/file conflict situation (otherwise
- * the "guilty" path would have already had such a
- * conflict in the original stage, either stage2
- * or stage3). Although its stage2 is synthesized
- * by overlaying the current index on top of "our
- * head" tree, --emu23 case also has this guarantee,
- * by calling add_cache_entry() to create such stage2
- * entries.
- *
- * (4) Only #2ALT and #3ALT lack the guarantee (1).
- * They resolve paths that exist only in stage2
- * or stage3. The stage2 tree may have a file DF
- * while stage3 tree may have a file DF/DF. If
- * #2ALT and #3ALT rules happen to apply to both
- * of them, we would end up having DF (coming from
- * stage2) and DF/DF (from stage3) in the result.
- * When we attempt to resolve a path that exists
- * only in stage2, we need to make sure there is
- * no path that would conflict with it in stage3
- * and vice versa.
- */
- if (c) { /* #2ALT */
- if (!causes_df_conflict(c, 2, dst, next, tail) &&
- (!old || same(c, old)))
- return merged_entry_allow_dirty(c, old, dst);
- }
- else { /* #3ALT */
- if (!causes_df_conflict(b, 3, dst, next, tail) &&
- (!old || same(b, old)))
- return merged_entry_allow_dirty(b, old, dst);
- }
- /* otherwise we will apply the original rule */
- }
- /* #14ALT */
- if (a && b && c && same(a, b) && !same(a, c)) {
- if (old && same(old, c))
- return merged_entry_allow_dirty(c, old, dst);
- /* otherwise the regular rule applies */
- }
- /*
- * If we have an entry in the index cache ("old"), then we want
- * to make sure that it matches any entries in stage 2 ("first
- * branch", aka "b").
- */
- if (old) {
- if (!b || !same(old, b))
- return -1;
- }
- merge = merge_entries(a, b, c);
- if (merge)
- return merged_entry(merge, old, dst);
- if (old)
- verify_uptodate(old);
- count = 0;
- if (a) { *dst++ = a; count++; }
- if (b) { *dst++ = b; count++; }
- if (c) { *dst++ = c; count++; }
- return count;
-}
-
-/*
- * Two-way merge.
- *
- * The rule is to "carry forward" what is in the index without losing
- * information across a "fast forward", favoring a successful merge
- * over a merge failure when it makes sense. For details of the
- * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
- *
- */
-static int twoway_merge(struct cache_entry **src, struct cache_entry **dst,
- struct cache_entry **next, int tail)
-{
- struct cache_entry *current = src[0];
- struct cache_entry *oldtree = src[1], *newtree = src[2];
-
- if (src[3])
- return -1;
-
- if (current) {
- if ((!oldtree && !newtree) || /* 4 and 5 */
- (!oldtree && newtree &&
- same(current, newtree)) || /* 6 and 7 */
- (oldtree && newtree &&
- same(oldtree, newtree)) || /* 14 and 15 */
- (oldtree && newtree &&
- !same(oldtree, newtree) && /* 18 and 19*/
- same(current, newtree))) {
- *dst++ = current;
- return 1;
- }
- else if (oldtree && !newtree && same(current, oldtree)) {
- /* 10 or 11 */
- return deleted_entry(oldtree, current, dst);
- }
- else if (oldtree && newtree &&
- same(current, oldtree) && !same(current, newtree)) {
- /* 20 or 21 */
- return merged_entry(newtree, current, dst);
- }
- else
- /* all other failures */
- return -1;
- }
- else if (newtree)
- return merged_entry(newtree, current, dst);
- else
- return deleted_entry(oldtree, current, dst);
-}
-
-/*
- * Two-way merge emulated with three-way merge.
- *
- * This treats "read-tree -m H M" by transforming it internally
- * into "read-tree -m H I+H M", where I+H is a tree that would
- * contain the contents of the current index file, overlayed on
- * top of H. Unlike the traditional two-way merge, this leaves
- * the stages in the resulting index file and lets the user resolve
- * the merge conflicts using standard tools for three-way merge.
- *
- * This function is just to set-up such an arrangement, and the
- * actual merge uses threeway_merge() function.
- */
-static void setup_emu23(void)
-{
- /* stage0 contains I, stage1 H, stage2 M.
- * move stage2 to stage3, and create stage2 entries
- * by scanning stage0 and stage1 entries.
- */
- int i, namelen, size;
- struct cache_entry *ce, *stage2;
-
- for (i = 0; i < active_nr; i++) {
- ce = active_cache[i];
- if (ce_stage(ce) != 2)
- continue;
- /* hoist them up to stage 3 */
- namelen = ce_namelen(ce);
- ce->ce_flags = create_ce_flags(namelen, 3);
- }
-
- for (i = 0; i < active_nr; i++) {
- ce = active_cache[i];
- if (ce_stage(ce) > 1)
- continue;
- namelen = ce_namelen(ce);
- size = cache_entry_size(namelen);
- stage2 = xmalloc(size);
- memcpy(stage2, ce, size);
- stage2->ce_flags = create_ce_flags(namelen, 2);
- if (add_cache_entry(stage2, ADD_CACHE_OK_TO_ADD) < 0)
- die("cannot merge index and our head tree");
-
- /* We are done with this name, so skip to next name */
- while (i < active_nr &&
- ce_namelen(active_cache[i]) == namelen &&
- !memcmp(active_cache[i]->name, ce->name, namelen))
- i++;
- i--; /* compensate for the loop control */
- }
-}
-
-/*
- * One-way merge.
- *
- * The rule is:
- * - take the stat information from stage0, take the data from stage1
- */
-static int oneway_merge(struct cache_entry **src, struct cache_entry **dst,
- struct cache_entry **next, int tail)
-{
- struct cache_entry *old = src[0];
- struct cache_entry *a = src[1];
-
- if (src[2] || src[3])
- return -1;
-
- if (!a)
- return 0;
- if (old && same(old, a)) {
- *dst++ = old;
- return 1;
- }
- return merged_entry(a, NULL, dst);
+ die("Entry '%s' would be overwritten by merge. Cannot merge.",
+ ce->name);
}
static void check_updates(struct cache_entry **src, int nr)
@@ -456,36 +250,280 @@
}
}
-typedef int (*merge_fn_t)(struct cache_entry **, struct cache_entry **, struct cache_entry **, int);
-
-static void merge_cache(struct cache_entry **src, int nr, merge_fn_t fn)
+static int unpack_trees(merge_fn_t fn)
{
- struct cache_entry **dst = src;
- int tail = nr;
-
- while (nr) {
- int entries;
- struct cache_entry *name, *ce, *stages[4] = { NULL, };
-
- name = ce = *src;
- for (;;) {
- int stage = ce_stage(ce);
- stages[stage] = ce;
- ce = *++src;
- active_nr--;
- if (!--nr)
- break;
- if (!path_matches(ce, name))
- break;
- }
-
- entries = fn(stages, dst, src, tail);
- if (entries < 0)
- reject_merge(name);
- dst += entries;
- active_nr += entries;
+ int indpos = 0;
+ unsigned len = object_list_length(trees);
+ struct tree_entry_list **posns =
+ xmalloc(len * sizeof(struct tree_entry_list *));
+ int i;
+ struct object_list *posn = trees;
+ merge_size = len;
+ for (i = 0; i < len; i++) {
+ posns[i] = ((struct tree *) posn->item)->entries;
+ posn = posn->next;
}
+ if (unpack_trees_rec(posns, len, "", fn, &indpos))
+ return -1;
+
check_updates(active_cache, active_nr);
+ return 0;
+}
+
+static int list_tree(unsigned char *sha1)
+{
+ struct tree *tree = parse_tree_indirect(sha1);
+ if (!tree)
+ return -1;
+ object_list_append(&tree->object, &trees);
+ return 0;
+}
+
+static int same(struct cache_entry *a, struct cache_entry *b)
+{
+ if (!!a != !!b)
+ return 0;
+ if (!a && !b)
+ return 1;
+ return a->ce_mode == b->ce_mode &&
+ !memcmp(a->sha1, b->sha1, 20);
+}
+
+
+/*
+ * When a CE gets turned into an unmerged entry, we
+ * want it to be up-to-date
+ */
+static void verify_uptodate(struct cache_entry *ce)
+{
+ struct stat st;
+
+ if (!lstat(ce->name, &st)) {
+ unsigned changed = ce_match_stat(ce, &st);
+ if (!changed)
+ return;
+ errno = 0;
+ }
+ if (errno == ENOENT)
+ return;
+ die("Entry '%s' not uptodate. Cannot merge.", ce->name);
+}
+
+static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
+{
+ merge->ce_flags |= htons(CE_UPDATE);
+ if (old) {
+ /*
+ * See if we can re-use the old CE directly?
+ * That way we get the uptodate stat info.
+ *
+ * This also removes the UPDATE flag on
+ * a match.
+ */
+ if (same(old, merge)) {
+ *merge = *old;
+ } else {
+ verify_uptodate(old);
+ }
+ }
+ merge->ce_flags &= ~htons(CE_STAGEMASK);
+ add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
+ return 1;
+}
+
+static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
+{
+ if (old)
+ verify_uptodate(old);
+ ce->ce_mode = 0;
+ add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
+ return 1;
+}
+
+static int keep_entry(struct cache_entry *ce)
+{
+ add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
+ return 1;
+}
+
+static int threeway_merge(struct cache_entry **stages)
+{
+ struct cache_entry *index;
+ struct cache_entry *head;
+ struct cache_entry *remote = stages[head_idx + 1];
+ int count;
+ int head_match = 0;
+ int remote_match = 0;
+
+ int df_conflict_head = 0;
+ int df_conflict_remote = 0;
+
+ int any_anc_missing = 0;
+ int i;
+
+ for (i = 1; i < head_idx; i++) {
+ if (!stages[i])
+ any_anc_missing = 1;
+ }
+
+ index = stages[0];
+ head = stages[head_idx];
+
+ if (head == &df_conflict_entry) {
+ df_conflict_head = 1;
+ head = NULL;
+ }
+
+ if (remote == &df_conflict_entry) {
+ df_conflict_remote = 1;
+ remote = NULL;
+ }
+
+ /* First, if there's a #16 situation, note that to prevent #13
+ * and #14.
+ */
+ if (!same(remote, head)) {
+ for (i = 1; i < head_idx; i++) {
+ if (same(stages[i], head)) {
+ head_match = 1;
+ }
+ if (same(stages[i], remote)) {
+ remote_match = 1;
+ }
+ }
+ }
+
+ /* We start with cases where the index is allowed to match
+ * something other than the head: #14(ALT) and #2ALT, where it
+ * is permitted to match the result instead.
+ */
+ /* #14, #14ALT, #2ALT */
+ if (remote && !df_conflict_head && head_match && !remote_match) {
+ if (index && !same(index, remote) && !same(index, head))
+ reject_merge(index);
+ return merged_entry(remote, index);
+ }
+ /*
+ * If we have an entry in the index cache, then we want to
+ * make sure that it matches head.
+ */
+ if (index && !same(index, head)) {
+ reject_merge(index);
+ }
+
+ if (head) {
+ /* #5ALT, #15 */
+ if (same(head, remote))
+ return merged_entry(head, index);
+ /* #13, #3ALT */
+ if (!df_conflict_remote && remote_match && !head_match)
+ return merged_entry(head, index);
+ }
+
+ /* #1 */
+ if (!head && !remote && any_anc_missing)
+ return 0;
+
+ /* Below are "no merge" cases, which require that the index be
+ * up-to-date to avoid the files getting overwritten with
+ * conflict resolution files.
+ */
+ if (index) {
+ verify_uptodate(index);
+ }
+
+ /* #2, #3, #4, #6, #7, #9, #11. */
+ count = 0;
+ if (!head_match || !remote_match) {
+ for (i = 1; i < head_idx; i++) {
+ if (stages[i]) {
+ keep_entry(stages[i]);
+ count++;
+ break;
+ }
+ }
+ }
+ if (head) { count += keep_entry(head); }
+ if (remote) { count += keep_entry(remote); }
+ return count;
+}
+
+/*
+ * Two-way merge.
+ *
+ * The rule is to "carry forward" what is in the index without losing
+ * information across a "fast forward", favoring a successful merge
+ * over a merge failure when it makes sense. For details of the
+ * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
+ *
+ */
+static int twoway_merge(struct cache_entry **src)
+{
+ struct cache_entry *current = src[0];
+ struct cache_entry *oldtree = src[1], *newtree = src[2];
+
+ if (merge_size != 2)
+ return error("Cannot do a twoway merge of %d trees\n",
+ merge_size);
+
+ if (current) {
+ if ((!oldtree && !newtree) || /* 4 and 5 */
+ (!oldtree && newtree &&
+ same(current, newtree)) || /* 6 and 7 */
+ (oldtree && newtree &&
+ same(oldtree, newtree)) || /* 14 and 15 */
+ (oldtree && newtree &&
+ !same(oldtree, newtree) && /* 18 and 19*/
+ same(current, newtree))) {
+ return keep_entry(current);
+ }
+ else if (oldtree && !newtree && same(current, oldtree)) {
+ /* 10 or 11 */
+ return deleted_entry(oldtree, current);
+ }
+ else if (oldtree && newtree &&
+ same(current, oldtree) && !same(current, newtree)) {
+ /* 20 or 21 */
+ return merged_entry(newtree, current);
+ }
+ else {
+ /* all other failures */
+ if (oldtree)
+ reject_merge(oldtree);
+ if (current)
+ reject_merge(current);
+ if (newtree)
+ reject_merge(newtree);
+ return -1;
+ }
+ }
+ else if (newtree)
+ return merged_entry(newtree, current);
+ else
+ return deleted_entry(oldtree, current);
+}
+
+/*
+ * One-way merge.
+ *
+ * The rule is:
+ * - take the stat information from stage0, take the data from stage1
+ */
+static int oneway_merge(struct cache_entry **src)
+{
+ struct cache_entry *old = src[0];
+ struct cache_entry *a = src[1];
+
+ if (merge_size != 1)
+ return error("Cannot do a oneway merge of %d trees\n",
+ merge_size);
+
+ if (!a)
+ return 0;
+ if (old && same(old, a)) {
+ return keep_entry(old);
+ }
+ return merged_entry(a, NULL);
}
static int read_cache_unmerged(void)
@@ -516,8 +554,9 @@
int main(int argc, char **argv)
{
- int i, newfd, merge, reset, emu23;
+ int i, newfd, reset, stage = 0;
unsigned char sha1[20];
+ merge_fn_t fn = NULL;
newfd = hold_index_file_for_update(&cache_file, get_index_file());
if (newfd < 0)
@@ -525,7 +564,6 @@
merge = 0;
reset = 0;
- emu23 = 0;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
@@ -537,7 +575,7 @@
/* This differs from "-m" in that we'll silently ignore unmerged entries */
if (!strcmp(arg, "--reset")) {
- if (stage || merge || emu23)
+ if (stage || merge)
usage(read_tree_usage);
reset = 1;
merge = 1;
@@ -546,9 +584,14 @@
continue;
}
+ if (!strcmp(arg, "--head")) {
+ head_idx = stage - 1;
+ fn = threeway_merge;
+ }
+
/* "-m" stands for "merge", meaning we start in stage 1 */
if (!strcmp(arg, "-m")) {
- if (stage || merge || emu23)
+ if (stage || merge)
usage(read_tree_usage);
if (read_cache_unmerged())
die("you need to resolve your current index first");
@@ -557,45 +600,41 @@
continue;
}
- /* "-emu23" uses 3-way merge logic to perform fast-forward */
- if (!strcmp(arg, "--emu23")) {
- if (stage || merge || emu23)
- usage(read_tree_usage);
- if (read_cache_unmerged())
- die("you need to resolve your current index first");
- merge = emu23 = stage = 1;
- continue;
- }
-
if (get_sha1(arg, sha1) < 0)
usage(read_tree_usage);
- if (stage > 3)
- usage(read_tree_usage);
- if (unpack_tree(sha1) < 0)
+ if (list_tree(sha1) < 0)
die("failed to unpack tree object %s", arg);
stage++;
}
if (update && !merge)
usage(read_tree_usage);
- if (merge) {
- static const merge_fn_t merge_function[] = {
- [1] = oneway_merge,
- [2] = twoway_merge,
- [3] = threeway_merge,
- };
- merge_fn_t fn;
-
- if (stage < 2 || stage > 4)
+ if (merge && !fn) {
+ if (stage < 2)
die("just how do you expect me to merge %d trees?", stage-1);
- if (emu23 && stage != 3)
- die("--emu23 takes only two trees");
- fn = merge_function[stage-1];
- if (stage == 3 && emu23) {
- setup_emu23();
- fn = merge_function[3];
+ switch (stage - 1) {
+ case 1:
+ fn = oneway_merge;
+ break;
+ case 2:
+ fn = twoway_merge;
+ break;
+ case 3:
+ fn = threeway_merge;
+ break;
+ default:
+ fn = threeway_merge;
+ break;
}
- merge_cache(active_cache, active_nr, fn);
}
+
+ if (head_idx < 0) {
+ if (stage - 1 >= 3)
+ head_idx = stage - 2;
+ else
+ head_idx = 1;
+ }
+
+ unpack_trees(fn);
if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
die("unable to write new index file");
diff --git a/t/t1005-read-tree-m-2way-emu23.sh b/t/t1005-read-tree-m-2way-emu23.sh
deleted file mode 100755
index 258a372..0000000
--- a/t/t1005-read-tree-m-2way-emu23.sh
+++ /dev/null
@@ -1,422 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) 2005 Junio C Hamano
-#
-
-test_description='Two way merge with read-tree --emu23 $H $M
-
-This test tries two-way merge (aka fast forward with carry forward).
-
-There is the head (called H) and another commit (called M), which is
-simply ahead of H. The index and the work tree contains a state that
-is derived from H, but may also have local changes. This test checks
-all the combinations described in the two-tree merge "carry forward"
-rules, found in <Documentation/git-rev-tree.txt>.
-
-In the test, these paths are used:
- bozbar - in H, stays in M, modified from bozbar to gnusto
- frotz - not in H added in M
- nitfol - in H, stays in M unmodified
- rezrov - in H, deleted in M
- yomin - not in H nor M
-'
-. ./test-lib.sh
-
-read_tree_twoway () {
- git-read-tree --emu23 "$1" "$2" &&
- git-ls-files --stage &&
- git-merge-index git-merge-one-file -a &&
- git-ls-files --stage
-}
-
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
-compare_change () {
- sed -n >current \
- -e '/^--- /d; /^+++ /d; /^@@ /d;' \
- -e 's/^\([-+][0-7][0-7][0-7][0-7][0-7][0-7]\) '"$_x40"' /\1 X /p' \
- "$1"
- diff -u expected current
-}
-
-check_cache_at () {
- clean_if_empty=`git-diff-files "$1"`
- case "$clean_if_empty" in
- '') echo "$1: clean" ;;
- ?*) echo "$1: dirty" ;;
- esac
- case "$2,$clean_if_empty" in
- clean,) : ;;
- clean,?*) false ;;
- dirty,) false ;;
- dirty,?*) : ;;
- esac
-}
-
-check_stages () {
- cat >expected_stages
- git-ls-files --stage | sed -e "s/ $_x40 / X /" >current_stages
- diff -u expected_stages current_stages
-}
-
-cat >bozbar-old <<\EOF
-This is a sample file used in two-way fast forward merge
-tests. Its second line ends with a magic word bozbar
-which will be modified by the merged head to gnusto.
-It has some extra lines so that external tools can
-successfully merge independent changes made to later
-lines (such as this one), avoiding line conflicts.
-EOF
-
-sed -e 's/bozbar/gnusto (earlier bozbar)/' bozbar-old >bozbar-new
-
-test_expect_success \
- setup \
- 'echo frotz >frotz &&
- echo nitfol >nitfol &&
- cat bozbar-old >bozbar &&
- echo rezrov >rezrov &&
- echo yomin >yomin &&
- git-update-index --add nitfol bozbar rezrov &&
- treeH=`git-write-tree` &&
- echo treeH $treeH &&
- git-ls-tree $treeH &&
-
- cat bozbar-new >bozbar &&
- git-update-index --add frotz bozbar --force-remove rezrov &&
- git-ls-files --stage >M.out &&
- treeM=`git-write-tree` &&
- echo treeM $treeM &&
- git-ls-tree $treeM &&
- git-diff-tree $treeH $treeM'
-
-# "read-tree -m H I+H M" but I is empty so this is "read-tree -m H H M".
-#
-# bozbar [O && A && B && O==A && O!=B (#14) ==> B] take M by read-tree
-# frotz [!O && !A && B (#2) ==> B] take M by read-tree
-# nitfol [O && A && B && O==A && O==B (#15) ==> B] take M by read-tree
-# rezrov [O && A && !B && O==A (#10) ==> no merge] removed by script
-#
-# Earlier one did not have #2ALT so taking M was done by the script,
-# which also updated the work tree and making frotz clean. With #2ALT,
-# this is resolved by read-tree itself and the path is left dirty
-# because we are not testing "read-tree -u --emu23".
-test_expect_success \
- '1, 2, 3 - no carry forward' \
- 'rm -f .git/index &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >1-3.out &&
- diff -u M.out 1-3.out &&
- check_cache_at bozbar dirty &&
- check_cache_at frotz dirty && # same as pure 2-way again.
- check_cache_at nitfol dirty'
-
-echo '+100644 X 0 yomin' >expected
-
-test_expect_success \
- '4 - carry forward local addition.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- git-update-index --add yomin &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >4.out || return 1
- diff -u M.out 4.out >4diff.out
- compare_change 4diff.out expected &&
- check_cache_at yomin clean'
-
-# "read-tree -m H I+H M" where !H && !M; so (I+H) not being up-to-date
-# should not matter. Thanks to #3ALT, this is now possible.
-test_expect_success \
- '5 - carry forward local addition.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo yomin >yomin &&
- git-update-index --add yomin &&
- echo yomin yomin >yomin &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >5.out || return 1
- diff -u M.out 5.out >5diff.out
- compare_change 5diff.out expected &&
- check_cache_at yomin dirty'
-
-# "read-tree -m H I+H M" where !H && M && (I+H) == M, so this should
-# succeed (even the entry is clean), now thanks to #5ALT.
-test_expect_success \
- '6 - local addition already has the same.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- git-update-index --add frotz &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >6.out &&
- diff -u M.out 6.out &&
- check_cache_at frotz clean'
-
-# Exactly the same pattern as above but with dirty cache. This also
-# should succeed, now thanks to #5ALT.
-test_expect_success \
- '7 - local addition already has the same.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo frotz >frotz &&
- git-update-index --add frotz &&
- echo frotz frotz >frotz &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >7.out &&
- diff -u M.out 7.out &&
- check_cache_at frotz dirty'
-
-test_expect_success \
- '8 - conflicting addition.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo frotz frotz >frotz &&
- git-update-index --add frotz &&
- if read_tree_twoway $treeH $treeM; then false; else :; fi'
-
-test_expect_success \
- '9 - conflicting addition.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo frotz frotz >frotz &&
- git-update-index --add frotz &&
- echo frotz >frotz &&
- if read_tree_twoway $treeH $treeM; then false; else :; fi'
-
-test_expect_success \
- '10 - path removed.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo rezrov >rezrov &&
- git-update-index --add rezrov &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >10.out &&
- diff -u M.out 10.out'
-
-test_expect_success \
- '11 - dirty path removed.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo rezrov >rezrov &&
- git-update-index --add rezrov &&
- echo rezrov rezrov >rezrov &&
- if read_tree_twoway $treeH $treeM; then false; else :; fi'
-
-test_expect_success \
- '12 - unmatching local changes being removed.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo rezrov rezrov >rezrov &&
- git-update-index --add rezrov &&
- if read_tree_twoway $treeH $treeM; then false; else :; fi'
-
-test_expect_success \
- '13 - unmatching local changes being removed.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo rezrov rezrov >rezrov &&
- git-update-index --add rezrov &&
- echo rezrov >rezrov &&
- if read_tree_twoway $treeH $treeM; then false; else :; fi'
-
-cat >expected <<EOF
--100644 X 0 nitfol
-+100644 X 0 nitfol
-EOF
-
-test_expect_success \
- '14 - unchanged in two heads.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo nitfol nitfol >nitfol &&
- git-update-index --add nitfol &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >14.out || return 1
- diff -u M.out 14.out >14diff.out
- compare_change 14diff.out expected &&
- check_cache_at nitfol clean'
-
-test_expect_success \
- '15 - unchanged in two heads.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo nitfol nitfol >nitfol &&
- git-update-index --add nitfol &&
- echo nitfol nitfol nitfol >nitfol &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >15.out || return 1
- diff -u M.out 15.out >15diff.out
- compare_change 15diff.out expected &&
- check_cache_at nitfol dirty'
-
-# This is different from straight 2-way merge in that it leaves
-# three stages of bozbar in the index file without failing, so
-# the user can run git-diff-stages to examine the situation.
-# With #2ALT, frotz is resolved internally.
-test_expect_success \
- '16 - conflicting local change.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo bozbar bozbar >bozbar &&
- git-update-index --add bozbar &&
- git-read-tree --emu23 $treeH $treeM &&
- check_stages' <<\EOF
-100644 X 1 bozbar
-100644 X 2 bozbar
-100644 X 3 bozbar
-100644 X 0 frotz
-100644 X 0 nitfol
-100644 X 1 rezrov
-100644 X 2 rezrov
-EOF
-
-test_expect_success \
- '17 - conflicting local change.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- echo bozbar bozbar >bozbar &&
- git-update-index --add bozbar &&
- echo bozbar bozbar bozbar >bozbar &&
- if read_tree_twoway $treeH $treeM; then false; else :; fi'
-
-test_expect_success \
- '18 - local change already having a good result.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- cat bozbar-new >bozbar &&
- git-update-index --add bozbar &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >18.out &&
- diff -u M.out 18.out &&
- check_cache_at bozbar clean'
-
-test_expect_success \
- '19 - local change already having a good result, further modified.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- cat bozbar-new >bozbar &&
- git-update-index --add bozbar &&
- echo gnusto gnusto >bozbar &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >19.out &&
- diff -u M.out 19.out &&
- check_cache_at bozbar dirty'
-
-test_expect_success \
- '20 - no local change, use new tree.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- cat bozbar-old >bozbar &&
- git-update-index --add bozbar &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >20.out &&
- diff -u M.out 20.out &&
- check_cache_at bozbar dirty'
-
-test_expect_success \
- '21 - no local change, dirty cache.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- cat bozbar-old >bozbar &&
- git-update-index --add bozbar &&
- echo gnusto gnusto >bozbar &&
- if read_tree_twoway $treeH $treeM; then false; else :; fi'
-
-echo '-100644 X 0 bozbar
-+100644 X 0 bozbar' >expected
-
-# This fails with straight two-way fast forward, but emu23
-# can merge them.
-test_expect_success \
- '22 - local change cache updated.' \
- 'rm -f .git/index &&
- git-read-tree $treeH &&
- git-checkout-index -u -f -q -a &&
- sed -e "s/such as/SUCH AS/" bozbar-old >bozbar &&
- git-update-index --add bozbar &&
- read_tree_twoway $treeH $treeM &&
- git-ls-files --stage >22.out || return 1
- diff -u M.out 22.out >22diff.out
- compare_change 22diff.out &&
- check_cache_at bozbar clean'
-
-# Also make sure we did not break DF vs DF/DF case.
-test_expect_success \
- 'DF vs DF/DF case setup.' \
- 'rm -f .git/index &&
- echo DF >DF &&
- git-update-index --add DF &&
- treeDF=`git-write-tree` &&
- echo treeDF $treeDF &&
- git-ls-tree $treeDF &&
- git-ls-files --stage >DF.out
-
- rm -f DF &&
- mkdir DF &&
- echo DF/DF >DF/DF &&
- git-update-index --add --remove DF DF/DF &&
- treeDFDF=`git-write-tree` &&
- echo treeDFDF $treeDFDF &&
- git-ls-tree $treeDFDF &&
- git-ls-files --stage >DFDF.out'
-
-test_expect_success \
- 'DF vs DF/DF case test (#1)' \
- 'rm -f .git/index &&
- rm -fr DF &&
- echo DF >DF &&
- git-update-index --add DF &&
- read_tree_twoway $treeDF $treeDFDF &&
- git-ls-files --stage >DFDFcheck.out &&
- diff -u DFDF.out DFDFcheck.out &&
- check_cache_at DF/DF clean && # different from pure 2-way
- :'
-
-# The other way around
-test_expect_success \
- 'DF vs DF/DF case test (#2)' \
- 'rm -f .git/index &&
- rm -fr DF &&
- mkdir DF &&
- echo DF/DF >DF/DF &&
- git-update-index --add DF/DF &&
- read_tree_twoway $treeDFDF $treeDF &&
- git-ls-files --stage >DFDFcheck.out &&
- diff -u DF.out DFDFcheck.out &&
- check_cache_at DF clean && # different from pure 2-way
- :'
-
-# Emu23 can grok I having more than H. Make sure we did not
-# botch the conflict tests (fixed).
-test_expect_success \
- 'DF vs DF/DF case test (#3).' \
- 'rm -f .git/index &&
- rm -fr DF &&
- mkdir DF &&
- echo DF/DF >DF/DF &&
- git-update-index --add DF/DF &&
- # This should fail because I and H have a conflict
- # at DF.
- if git-read-tree --emu23 $treeDF $treeDFDF
- then false
- else true
- fi'
-
-test_done
