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Merge branch 'kb/full-history-compute-treesame-carefully-2'

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Major update to the revision traversal logic to improve culling of
irrelevant parents while traversing a mergy history.

* kb/full-history-compute-treesame-carefully-2:
  revision.c: make default history consider bottom commits
  revision.c: don't show all merges for --parents
  revision.c: discount side branches when computing TREESAME
  revision.c: add BOTTOM flag for commits
  simplify-merges: drop merge from irrelevant side branch
  simplify-merges: never remove all TREESAME parents
  t6012: update test for tweaked full-history traversal
  revision.c: Make --full-history consider more merges
  Documentation: avoid "uninteresting"
  rev-list-options.txt: correct TREESAME for P
  t6111: add parents to tests
  t6111: allow checking the parents as well
  t6111: new TREESAME test set
  t6019: test file dropped in -s ours merge
  decorate.c: compact table when growing
This commit is contained in:
Junio C Hamano 2013-06-14 08:45:59 -07:00
parent 91d34bc47b 141efdba57
commit b27a79d16b
7 changed files with 750 additions and 91 deletions
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42
Documentation/rev-list-options.txt
View file

@ -271,8 +271,8 @@ See also linkgit:git-reflog[1].
--boundary::
Output uninteresting commits at the boundary, which are usually
not shown.
Output excluded boundary commits. Boundary commits are
prefixed with `-`.
--
@ -342,13 +342,13 @@ In the following, we will always refer to the same example history to
illustrate the differences between simplification settings. We assume
that you are filtering for a file `foo` in this commit graph:
-----------------------------------------------------------------------
.-A---M---N---O---P
/ / / / /
I B C D E
\ / / / /
`-------------'
.-A---M---N---O---P---Q
/ / / / / /
I B C D E Y
\ / / / / /
`-------------' X
-----------------------------------------------------------------------
The horizontal line of history A---P is taken to be the first parent of
The horizontal line of history A---Q is taken to be the first parent of
each merge. The commits are:
* `I` is the initial commit, in which `foo` exists with contents
@ -367,8 +367,11 @@ each merge. The commits are:
`N` and `D` to "foobarbaz"; i.e., it is not TREESAME to any parent.
* `E` changes `quux` to "xyzzy", and its merge `P` combines the
strings to "quux xyzzy". Despite appearing interesting, `P` is
TREESAME to all parents.
strings to "quux xyzzy". `P` is TREESAME to `O`, but not to `E`.
* `X` is an indpendent root commit that added a new file `side`, and `Y`
modified it. `Y` is TREESAME to `X`. Its merge `Q` added `side` to `P`, and
`Q` is TREESAME to `P`, but not to `Y`.
'rev-list' walks backwards through history, including or excluding
commits based on whether '\--full-history' and/or parent rewriting
@ -410,10 +413,10 @@ parent lines.
the example, we get
+
-----------------------------------------------------------------------
I A B N D O
I A B N D O P Q
-----------------------------------------------------------------------
+
`P` and `M` were excluded because they are TREESAME to a parent. `E`,
`M` was excluded because it is TREESAME to both parents. `E`,
`C` and `B` were all walked, but only `B` was !TREESAME, so the others
do not appear.
+
@ -431,7 +434,7 @@ Along each parent, prune away commits that are not included
themselves. This results in
+
-----------------------------------------------------------------------
.-A---M---N---O---P
.-A---M---N---O---P---Q
/ / / / /
I B / D /
\ / / / /
@ -441,7 +444,7 @@ themselves. This results in
Compare to '\--full-history' without rewriting above. Note that `E`
was pruned away because it is TREESAME, but the parent list of P was
rewritten to contain `E`'s parent `I`. The same happened for `C` and
`N`. Note also that `P` was included despite being TREESAME.
`N`, and `X`, `Y` and `Q`.
In addition to the above settings, you can change whether TREESAME
affects inclusion:
@ -471,8 +474,9 @@ history according to the following rules:
* Set `C'` to `C`.
+
* Replace each parent `P` of `C'` with its simplification `P'`. In
the process, drop parents that are ancestors of other parents, and
remove duplicates.
the process, drop parents that are ancestors of other parents or that are
root commits TREESAME to an empty tree, and remove duplicates, but take care
to never drop all parents that we are TREESAME to.
+
* If after this parent rewriting, `C'` is a root or merge commit (has
zero or >1 parents), a boundary commit, or !TREESAME, it remains.
@ -490,7 +494,7 @@ The effect of this is best shown by way of comparing to
`---------'
-----------------------------------------------------------------------
+
Note the major differences in `N` and `P` over '--full-history':
Note the major differences in `N`, `P` and `Q` over '--full-history':
+
--
* `N`'s parent list had `I` removed, because it is an ancestor of the
@ -498,6 +502,10 @@ Note the major differences in `N` and `P` over '--full-history':
+
* `P`'s parent list similarly had `I` removed. `P` was then
removed completely, because it had one parent and is TREESAME.
+
* `Q`'s parent list had `Y` simplified to `X`. `X` was then removed, because it
was a TREESAME root. `Q` was then removed completely, because it had one
parent and is TREESAME.
--
Finally, there is a fifth simplification mode available:

2
decorate.c
View file

@ -49,7 +49,7 @@ static void grow_decoration(struct decoration *n)
const struct object *base = old_hash[i].base;
void *decoration = old_hash[i].decoration;
if (!base)
if (!decoration)
continue;
insert_decoration(n, base, decoration);
}

539
revision.c
View file

@ -333,6 +333,80 @@ static int everybody_uninteresting(struct commit_list *orig)
return 1;
}
/*
* A definition of "relevant" commit that we can use to simplify limited graphs
* by eliminating side branches.
*
* A "relevant" commit is one that is !UNINTERESTING (ie we are including it
* in our list), or that is a specified BOTTOM commit. Then after computing
* a limited list, during processing we can generally ignore boundary merges
* coming from outside the graph, (ie from irrelevant parents), and treat
* those merges as if they were single-parent. TREESAME is defined to consider
* only relevant parents, if any. If we are TREESAME to our on-graph parents,
* we don't care if we were !TREESAME to non-graph parents.
*
* Treating bottom commits as relevant ensures that a limited graph's
* connection to the actual bottom commit is not viewed as a side branch, but
* treated as part of the graph. For example:
*
* ....Z...A---X---o---o---B
* . /
* W---Y
*
* When computing "A..B", the A-X connection is at least as important as
* Y-X, despite A being flagged UNINTERESTING.
*
* And when computing --ancestry-path "A..B", the A-X connection is more
* important than Y-X, despite both A and Y being flagged UNINTERESTING.
*/
static inline int relevant_commit(struct commit *commit)
{
return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
}
/*
* Return a single relevant commit from a parent list. If we are a TREESAME
* commit, and this selects one of our parents, then we can safely simplify to
* that parent.
*/
static struct commit *one_relevant_parent(const struct rev_info *revs,
struct commit_list *orig)
{
struct commit_list *list = orig;
struct commit *relevant = NULL;
if (!orig)
return NULL;
/*
* For 1-parent commits, or if first-parent-only, then return that
* first parent (even if not "relevant" by the above definition).
* TREESAME will have been set purely on that parent.
*/
if (revs->first_parent_only || !orig->next)
return orig->item;
/*
* For multi-parent commits, identify a sole relevant parent, if any.
* If we have only one relevant parent, then TREESAME will be set purely
* with regard to that parent, and we can simplify accordingly.
*
* If we have more than one relevant parent, or no relevant parents
* (and multiple irrelevant ones), then we can't select a parent here
* and return NULL.
*/
while (list) {
struct commit *commit = list->item;
list = list->next;
if (relevant_commit(commit)) {
if (relevant)
return NULL;
relevant = commit;
}
}
return relevant;
}
/*
* The goal is to get REV_TREE_NEW as the result only if the
* diff consists of all '+' (and no other changes), REV_TREE_OLD
@ -430,10 +504,125 @@ static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
return retval >= 0 && (tree_difference == REV_TREE_SAME);
}
struct treesame_state {
unsigned int nparents;
unsigned char treesame[FLEX_ARRAY];
};
static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
{
unsigned n = commit_list_count(commit->parents);
struct treesame_state *st = xcalloc(1, sizeof(*st) + n);
st->nparents = n;
add_decoration(&revs->treesame, &commit->object, st);
return st;
}
/*
* Must be called immediately after removing the nth_parent from a commit's
* parent list, if we are maintaining the per-parent treesame[] decoration.
* This does not recalculate the master TREESAME flag - update_treesame()
* should be called to update it after a sequence of treesame[] modifications
* that may have affected it.
*/
static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
{
struct treesame_state *st;
int old_same;
if (!commit->parents) {
/*
* Have just removed the only parent from a non-merge.
* Different handling, as we lack decoration.
*/
if (nth_parent != 0)
die("compact_treesame %u", nth_parent);
old_same = !!(commit->object.flags & TREESAME);
if (rev_same_tree_as_empty(revs, commit))
commit->object.flags |= TREESAME;
else
commit->object.flags &= ~TREESAME;
return old_same;
}
st = lookup_decoration(&revs->treesame, &commit->object);
if (!st || nth_parent >= st->nparents)
die("compact_treesame %u", nth_parent);
old_same = st->treesame[nth_parent];
memmove(st->treesame + nth_parent,
st->treesame + nth_parent + 1,
st->nparents - nth_parent - 1);
/*
* If we've just become a non-merge commit, update TREESAME
* immediately, and remove the no-longer-needed decoration.
* If still a merge, defer update until update_treesame().
*/
if (--st->nparents == 1) {
if (commit->parents->next)
die("compact_treesame parents mismatch");
if (st->treesame[0] && revs->dense)
commit->object.flags |= TREESAME;
else
commit->object.flags &= ~TREESAME;
free(add_decoration(&revs->treesame, &commit->object, NULL));
}
return old_same;
}
static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
{
if (commit->parents && commit->parents->next) {
unsigned n;
struct treesame_state *st;
struct commit_list *p;
unsigned relevant_parents;
unsigned relevant_change, irrelevant_change;
st = lookup_decoration(&revs->treesame, &commit->object);
if (!st)
die("update_treesame %s", sha1_to_hex(commit->object.sha1));
relevant_parents = 0;
relevant_change = irrelevant_change = 0;
for (p = commit->parents, n = 0; p; n++, p = p->next) {
if (relevant_commit(p->item)) {
relevant_change |= !st->treesame[n];
relevant_parents++;
} else
irrelevant_change |= !st->treesame[n];
}
if (relevant_parents ? relevant_change : irrelevant_change)
commit->object.flags &= ~TREESAME;
else
commit->object.flags |= TREESAME;
}
return commit->object.flags & TREESAME;
}
static inline int limiting_can_increase_treesame(const struct rev_info *revs)
{
/*
* TREESAME is irrelevant unless prune && dense;
* if simplify_history is set, we can't have a mixture of TREESAME and
* !TREESAME INTERESTING parents (and we don't have treesame[]
* decoration anyway);
* if first_parent_only is set, then the TREESAME flag is locked
* against the first parent (and again we lack treesame[] decoration).
*/
return revs->prune && revs->dense &&
!revs->simplify_history &&
!revs->first_parent_only;
}
static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
{
struct commit_list **pp, *parent;
int tree_changed = 0, tree_same = 0, nth_parent = 0;
struct treesame_state *ts = NULL;
int relevant_change = 0, irrelevant_change = 0;
int relevant_parents, nth_parent;
/*
* If we don't do pruning, everything is interesting
@ -457,33 +646,54 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
if (!revs->dense && !commit->parents->next)
return;
pp = &commit->parents;
while ((parent = *pp) != NULL) {
for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
(parent = *pp) != NULL;
pp = &parent->next, nth_parent++) {
struct commit *p = parent->item;
if (relevant_commit(p))
relevant_parents++;
/*
* Do not compare with later parents when we care only about
* the first parent chain, in order to avoid derailing the
* traversal to follow a side branch that brought everything
* in the path we are limited to by the pathspec.
*/
if (revs->first_parent_only && nth_parent++)
break;
if (nth_parent == 1) {
/*
* This our second loop iteration - so we now know
* we're dealing with a merge.
*
* Do not compare with later parents when we care only about
* the first parent chain, in order to avoid derailing the
* traversal to follow a side branch that brought everything
* in the path we are limited to by the pathspec.
*/
if (revs->first_parent_only)
break;
/*
* If this will remain a potentially-simplifiable
* merge, remember per-parent treesame if needed.
* Initialise the array with the comparison from our
* first iteration.
*/
if (revs->treesame.name &&
!revs->simplify_history &&
!(commit->object.flags & UNINTERESTING)) {
ts = initialise_treesame(revs, commit);
if (!(irrelevant_change || relevant_change))
ts->treesame[0] = 1;
}
}
if (parse_commit(p) < 0)
die("cannot simplify commit %s (because of %s)",
sha1_to_hex(commit->object.sha1),
sha1_to_hex(p->object.sha1));
switch (rev_compare_tree(revs, p, commit)) {
case REV_TREE_SAME:
tree_same = 1;
if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
if (!revs->simplify_history || !relevant_commit(p)) {
/* Even if a merge with an uninteresting
* side branch brought the entire change
* we are interested in, we do not want
* to lose the other branches of this
* merge, so we just keep going.
*/
pp = &parent->next;
if (ts)
ts->treesame[nth_parent] = 1;
continue;
}
parent->next = NULL;
@ -511,15 +721,27 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
/* fallthrough */
case REV_TREE_OLD:
case REV_TREE_DIFFERENT:
tree_changed = 1;
pp = &parent->next;
if (relevant_commit(p))
relevant_change = 1;
else
irrelevant_change = 1;
continue;
}
die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
}
if (tree_changed && !tree_same)
return;
commit->object.flags |= TREESAME;
/*
* TREESAME is straightforward for single-parent commits. For merge
* commits, it is most useful to define it so that "irrelevant"
* parents cannot make us !TREESAME - if we have any relevant
* parents, then we only consider TREESAMEness with respect to them,
* allowing irrelevant merges from uninteresting branches to be
* simplified away. Only if we have only irrelevant parents do we
* base TREESAME on them. Note that this logic is replicated in
* update_treesame, which should be kept in sync.
*/
if (relevant_parents ? !relevant_change : !irrelevant_change)
commit->object.flags |= TREESAME;
}
static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
@ -802,16 +1024,12 @@ static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *li
* to filter the result of "A..B" further to the ones that can actually
* reach A.
*/
static struct commit_list *collect_bottom_commits(struct rev_info *revs)
static struct commit_list *collect_bottom_commits(struct commit_list *list)
{
struct commit_list *bottom = NULL;
int i;
for (i = 0; i < revs->cmdline.nr; i++) {
struct rev_cmdline_entry *elem = &revs->cmdline.rev[i];
if ((elem->flags & UNINTERESTING) &&
elem->item->type == OBJ_COMMIT)
commit_list_insert((struct commit *)elem->item, &bottom);
}
struct commit_list *elem, *bottom = NULL;
for (elem = list; elem; elem = elem->next)
if (elem->item->object.flags & BOTTOM)
commit_list_insert(elem->item, &bottom);
return bottom;
}
@ -842,7 +1060,7 @@ static int limit_list(struct rev_info *revs)
struct commit_list *bottom = NULL;
if (revs->ancestry_path) {
bottom = collect_bottom_commits(revs);
bottom = collect_bottom_commits(list);
if (!bottom)
die("--ancestry-path given but there are no bottom commits");
}
@ -895,6 +1113,18 @@ static int limit_list(struct rev_info *revs)
free_commit_list(bottom);
}
/*
* Check if any commits have become TREESAME by some of their parents
* becoming UNINTERESTING.
*/
if (limiting_can_increase_treesame(revs))
for (list = newlist; list; list = list->next) {
struct commit *c = list->item;
if (c->object.flags & (UNINTERESTING | TREESAME))
continue;
update_treesame(revs, c);
}
revs->commits = newlist;
return 0;
}
@ -1014,7 +1244,7 @@ static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
const char *arg = arg_;
if (*arg == '^') {
flags ^= UNINTERESTING;
flags ^= UNINTERESTING | BOTTOM;
arg++;
}
if (get_sha1_committish(arg, sha1))
@ -1106,8 +1336,8 @@ static void prepare_show_merge(struct rev_info *revs)
add_pending_object(revs, &head->object, "HEAD");
add_pending_object(revs, &other->object, "MERGE_HEAD");
bases = get_merge_bases(head, other, 1);
add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING);
add_pending_commit_list(revs, bases, UNINTERESTING);
add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
free_commit_list(bases);
head->object.flags |= SYMMETRIC_LEFT;
@ -1143,13 +1373,15 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
unsigned get_sha1_flags = 0;
flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
dotdot = strstr(arg, "..");
if (dotdot) {
unsigned char from_sha1[20];
const char *next = dotdot + 2;
const char *this = arg;
int symmetric = *next == '.';
unsigned int flags_exclude = flags ^ UNINTERESTING;
unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
static const char head_by_default[] = "HEAD";
unsigned int a_flags;
@ -1225,13 +1457,13 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
dotdot = strstr(arg, "^!");
if (dotdot && !dotdot[2]) {
*dotdot = 0;
if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM)))
*dotdot = '^';
}
local_flags = 0;
if (*arg == '^') {
local_flags = UNINTERESTING;
local_flags = UNINTERESTING | BOTTOM;
arg++;
}
@ -1708,7 +1940,7 @@ static int handle_revision_pseudo_opt(const char *submodule,
handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
} else if (!strcmp(arg, "--bisect")) {
handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
handle_refs(submodule, revs, *flags ^ UNINTERESTING, for_each_good_bisect_ref);
handle_refs(submodule, revs, *flags ^ (UNINTERESTING | BOTTOM), for_each_good_bisect_ref);
revs->bisect = 1;
} else if (!strcmp(arg, "--tags")) {
handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
@ -1734,7 +1966,7 @@ static int handle_revision_pseudo_opt(const char *submodule,
} else if (!strcmp(arg, "--reflog")) {
handle_reflog(revs, *flags);
} else if (!strcmp(arg, "--not")) {
*flags ^= UNINTERESTING;
*flags ^= UNINTERESTING | BOTTOM;
} else if (!strcmp(arg, "--no-walk")) {
revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
} else if (!prefixcmp(arg, "--no-walk=")) {
@ -1954,28 +2186,32 @@ static void add_child(struct rev_info *revs, struct commit *parent, struct commi
l->next = add_decoration(&revs->children, &parent->object, l);
}
static int remove_duplicate_parents(struct commit *commit)
static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
{
struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
struct commit_list **pp, *p;
int surviving_parents;
/* Examine existing parents while marking ones we have seen... */
pp = &commit->parents;
surviving_parents = 0;
while ((p = *pp) != NULL) {
struct commit *parent = p->item;
if (parent->object.flags & TMP_MARK) {
*pp = p->next;
if (ts)
compact_treesame(revs, commit, surviving_parents);
continue;
}
parent->object.flags |= TMP_MARK;
surviving_parents++;
pp = &p->next;
}
/* count them while clearing the temporary mark */
surviving_parents = 0;
/* clear the temporary mark */
for (p = commit->parents; p; p = p->next) {
p->item->object.flags &= ~TMP_MARK;
surviving_parents++;
}
/* no update_treesame() - removing duplicates can't affect TREESAME */
return surviving_parents;
}
@ -1995,9 +2231,157 @@ static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs,
return st;
}
static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
{
struct commit_list *h = reduce_heads(commit->parents);
int i = 0, marked = 0;
struct commit_list *po, *pn;
/* Want these for sanity-checking only */
int orig_cnt = commit_list_count(commit->parents);
int cnt = commit_list_count(h);
/*
* Not ready to remove items yet, just mark them for now, based
* on the output of reduce_heads(). reduce_heads outputs the reduced
* set in its original order, so this isn't too hard.
*/
po = commit->parents;
pn = h;
while (po) {
if (pn && po->item == pn->item) {
pn = pn->next;
i++;
} else {
po->item->object.flags |= TMP_MARK;
marked++;
}
po=po->next;
}
if (i != cnt || cnt+marked != orig_cnt)
die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
free_commit_list(h);
return marked;
}
static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
{
struct commit_list *p;
int marked = 0;
for (p = commit->parents; p; p = p->next) {
struct commit *parent = p->item;
if (!parent->parents && (parent->object.flags & TREESAME)) {
parent->object.flags |= TMP_MARK;
marked++;
}
}
return marked;
}
/*
* Awkward naming - this means one parent we are TREESAME to.
* cf mark_treesame_root_parents: root parents that are TREESAME (to an
* empty tree). Better name suggestions?
*/
static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
{
struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
struct commit *unmarked = NULL, *marked = NULL;
struct commit_list *p;
unsigned n;
for (p = commit->parents, n = 0; p; p = p->next, n++) {
if (ts->treesame[n]) {
if (p->item->object.flags & TMP_MARK) {
if (!marked)
marked = p->item;
} else {
if (!unmarked) {
unmarked = p->item;
break;
}
}
}
}
/*
* If we are TREESAME to a marked-for-deletion parent, but not to any
* unmarked parents, unmark the first TREESAME parent. This is the
* parent that the default simplify_history==1 scan would have followed,
* and it doesn't make sense to omit that path when asking for a
* simplified full history. Retaining it improves the chances of
* understanding odd missed merges that took an old version of a file.
*
* Example:
*
* I--------*X A modified the file, but mainline merge X used
* \ / "-s ours", so took the version from I. X is
* `-*A--' TREESAME to I and !TREESAME to A.
*
* Default log from X would produce "I". Without this check,
* --full-history --simplify-merges would produce "I-A-X", showing
* the merge commit X and that it changed A, but not making clear that
* it had just taken the I version. With this check, the topology above
* is retained.
*
* Note that it is possible that the simplification chooses a different
* TREESAME parent from the default, in which case this test doesn't
* activate, and we _do_ drop the default parent. Example:
*
* I------X A modified the file, but it was reverted in B,
* \ / meaning mainline merge X is TREESAME to both
* *A-*B parents.
*
* Default log would produce "I" by following the first parent;
* --full-history --simplify-merges will produce "I-A-B". But this is a
* reasonable result - it presents a logical full history leading from
* I to X, and X is not an important merge.
*/
if (!unmarked && marked) {
marked->object.flags &= ~TMP_MARK;
return 1;
}
return 0;
}
static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
{
struct commit_list **pp, *p;
int nth_parent, removed = 0;
pp = &commit->parents;
nth_parent = 0;
while ((p = *pp) != NULL) {
struct commit *parent = p->item;
if (parent->object.flags & TMP_MARK) {
parent->object.flags &= ~TMP_MARK;
*pp = p->next;
free(p);
removed++;
compact_treesame(revs, commit, nth_parent);
continue;
}
pp = &p->next;
nth_parent++;
}
/* Removing parents can only increase TREESAMEness */
if (removed && !(commit->object.flags & TREESAME))
update_treesame(revs, commit);
return nth_parent;
}
static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
{
struct commit_list *p;
struct commit *parent;
struct merge_simplify_state *st, *pst;
int cnt;
@ -2039,7 +2423,9 @@ static struct commit_list **simplify_one(struct rev_info *revs, struct commit *c
}
/*
* Rewrite our list of parents.
* Rewrite our list of parents. Note that this cannot
* affect our TREESAME flags in any way - a commit is
* always TREESAME to its simplification.
*/
for (p = commit->parents; p; p = p->next) {
pst = locate_simplify_state(revs, p->item);
@ -2051,43 +2437,53 @@ static struct commit_list **simplify_one(struct rev_info *revs, struct commit *c
if (revs->first_parent_only)
cnt = 1;
else
cnt = remove_duplicate_parents(commit);
cnt = remove_duplicate_parents(revs, commit);
/*
* It is possible that we are a merge and one side branch
* does not have any commit that touches the given paths;
* in such a case, the immediate parents will be rewritten
* to different commits.
* in such a case, the immediate parent from that branch
* will be rewritten to be the merge base.
*
* o----X X: the commit we are looking at;
* / / o: a commit that touches the paths;
* ---o----'
*
* Further reduce the parents by removing redundant parents.
* Further, a merge of an independent branch that doesn't
* touch the path will reduce to a treesame root parent:
*
* ----o----X X: the commit we are looking at;
* / o: a commit that touches the paths;
* r r: a root commit not touching the paths
*
* Detect and simplify both cases.
*/
if (1 < cnt) {
struct commit_list *h = reduce_heads(commit->parents);
cnt = commit_list_count(h);
free_commit_list(commit->parents);
commit->parents = h;
int marked = mark_redundant_parents(revs, commit);
marked += mark_treesame_root_parents(revs, commit);
if (marked)
marked -= leave_one_treesame_to_parent(revs, commit);
if (marked)
cnt = remove_marked_parents(revs, commit);
}
/*
* A commit simplifies to itself if it is a root, if it is
* UNINTERESTING, if it touches the given paths, or if it is a
* merge and its parents simplifies to more than one commits
* merge and its parents don't simplify to one relevant commit
* (the first two cases are already handled at the beginning of
* this function).
*
* Otherwise, it simplifies to what its sole parent simplifies to.
* Otherwise, it simplifies to what its sole relevant parent
* simplifies to.
*/
if (!cnt ||
(commit->object.flags & UNINTERESTING) ||
!(commit->object.flags & TREESAME) ||
(1 < cnt))
(parent = one_relevant_parent(revs, commit->parents)) == NULL)
st->simplified = commit;
else {
pst = locate_simplify_state(revs, commit->parents->item);
pst = locate_simplify_state(revs, parent);
st->simplified = pst->simplified;
}
return tail;
@ -2183,6 +2579,11 @@ int prepare_revision_walk(struct rev_info *revs)
if (!revs->leak_pending)
free(list);
/* Signal whether we need per-parent treesame decoration */
if (revs->simplify_merges ||
(revs->limited && limiting_can_increase_treesame(revs)))
revs->treesame.name = "treesame";
if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
commit_list_sort_by_date(&revs->commits);
if (revs->no_walk)
@ -2210,15 +2611,15 @@ static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp
if (!revs->limited)
if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
return rewrite_one_error;
if (p->parents && p->parents->next)
return rewrite_one_ok;
if (p->object.flags & UNINTERESTING)
return rewrite_one_ok;
if (!(p->object.flags & TREESAME))
return rewrite_one_ok;
if (!p->parents)
return rewrite_one_noparents;
*pp = p->parents->item;
if ((p = one_relevant_parent(revs, p->parents)) == NULL)
return rewrite_one_ok;
*pp = p;
}
}
@ -2239,7 +2640,7 @@ int rewrite_parents(struct rev_info *revs, struct commit *commit,
}
pp = &parent->next;
}
remove_duplicate_parents(commit);
remove_duplicate_parents(revs, commit);
return 0;
}
@ -2363,10 +2764,7 @@ enum commit_action get_commit_action(struct rev_info *revs, struct commit *commi
if (revs->min_age != -1 && (commit->date > revs->min_age))
return commit_ignore;
if (revs->min_parents || (revs->max_parents >= 0)) {
int n = 0;
struct commit_list *p;
for (p = commit->parents; p; p = p->next)
n++;
int n = commit_list_count(commit->parents);
if ((n < revs->min_parents) ||
((revs->max_parents >= 0) && (n > revs->max_parents)))
return commit_ignore;
@ -2376,12 +2774,23 @@ enum commit_action get_commit_action(struct rev_info *revs, struct commit *commi
if (revs->prune && revs->dense) {
/* Commit without changes? */
if (commit->object.flags & TREESAME) {
int n;
struct commit_list *p;
/* drop merges unless we want parenthood */
if (!want_ancestry(revs))
return commit_ignore;
/* non-merge - always ignore it */
if (!commit->parents || !commit->parents->next)
return commit_ignore;
/*
* If we want ancestry, then need to keep any merges
* between relevant commits to tie together topology.
* For consistency with TREESAME and simplification
* use "relevant" here rather than just INTERESTING,
* to treat bottom commit(s) as part of the topology.
*/
for (n = 0, p = commit->parents; p; p = p->next)
if (relevant_commit(p->item))
if (++n >= 2)
return commit_show;
return commit_ignore;
}
}
return commit_show;

4
revision.h
View file

@ -15,7 +15,8 @@
#define ADDED (1u<<7) /* Parents already parsed and added? */
#define SYMMETRIC_LEFT (1u<<8)
#define PATCHSAME (1u<<9)
#define ALL_REV_FLAGS ((1u<<10)-1)
#define BOTTOM (1u<<10)
#define ALL_REV_FLAGS ((1u<<11)-1)
#define DECORATE_SHORT_REFS 1
#define DECORATE_FULL_REFS 2
@ -169,6 +170,7 @@ struct rev_info {
struct reflog_walk_info *reflog_info;
struct decoration children;
struct decoration merge_simplification;
struct decoration treesame;
/* notes-specific options: which refs to show */
struct display_notes_opt notes_opt;

31
t/t6012-rev-list-simplify.sh
View file

@ -14,21 +14,24 @@ unnote () {
test_expect_success setup '
echo "Hi there" >file &&
git add file &&
test_tick && git commit -m "Initial file" &&
echo "initial" >lost &&
git add file lost &&
test_tick && git commit -m "Initial file and lost" &&
note A &&
git branch other-branch &&
echo "Hello" >file &&
git add file &&
test_tick && git commit -m "Modified file" &&
echo "second" >lost &&
git add file lost &&
test_tick && git commit -m "Modified file and lost" &&
note B &&
git checkout other-branch &&
echo "Hello" >file &&
git add file &&
>lost &&
git add file lost &&
test_tick && git commit -m "Modified the file identically" &&
note C &&
@ -37,7 +40,9 @@ test_expect_success setup '
test_tick && git commit -m "Add another file" &&
note D &&
test_tick && git merge -m "merge" master &&
test_tick &&
test_must_fail git merge -m "merge" master &&
>lost && git commit -a -m "merge" &&
note E &&
echo "Yet another" >elif &&
@ -105,9 +110,21 @@ check_result 'L K J I H G F E D C B A' --full-history
check_result 'K I H E C B A' --full-history -- file
check_result 'K I H E C B A' --full-history --topo-order -- file
check_result 'K I H E C B A' --full-history --date-order -- file
check_outcome failure 'I E C B A' --simplify-merges -- file
check_result 'I E C B A' --simplify-merges -- file
check_result 'I B A' -- file
check_result 'I B A' --topo-order -- file
check_result 'H' --first-parent -- another-file
check_result 'E C B A' --full-history E -- lost
test_expect_success 'full history simplification without parent' '
printf "%s\n" E C B A >expect &&
git log --pretty="$FMT" --full-history E -- lost |
unnote >actual &&
sed -e "s/^.* \([^ ]*\) .*/\1/" >check <actual &&
test_cmp expect check || {
cat actual
false
}
'
test_done

27
t/t6019-rev-list-ancestry-path.sh
View file

@ -16,6 +16,10 @@ test_description='--ancestry-path'
#
# F...I == F G H I
# --ancestry-path F...I == F H I
#
# G..M -- G.t == [nothing - was dropped in "-s ours" merge L]
# --ancestry-path G..M -- G.t == L
# --ancestry-path --simplify-merges G^..M -- G.t == G L
. ./test-lib.sh
@ -89,6 +93,29 @@ test_expect_success 'rev-list --ancestry-path F...I' '
test_cmp expect actual
'
# G.t is dropped in an "-s ours" merge
test_expect_success 'rev-list G..M -- G.t' '
>expect &&
git rev-list --format=%s G..M -- G.t |
sed -e "/^commit /d" >actual &&
test_cmp expect actual
'
test_expect_success 'rev-list --ancestry-path G..M -- G.t' '
echo L >expect &&
git rev-list --ancestry-path --format=%s G..M -- G.t |
sed -e "/^commit /d" >actual &&
test_cmp expect actual
'
test_expect_success 'rev-list --ancestry-path --simplify-merges G^..M -- G.t' '
for c in G L; do echo $c; done >expect &&
git rev-list --ancestry-path --simplify-merges --format=%s G^..M -- G.t |
sed -e "/^commit /d" |
sort >actual &&
test_cmp expect actual
'
# b---bc
# / \ /
# a X

196
t/t6111-rev-list-treesame.sh Executable file
View file

@ -0,0 +1,196 @@
#!/bin/sh
#
# ,---E--. *H----------. * marks !TREESAME parent paths
# / \ / \*
# *A--*B---D--*F-*G---------K-*L-*M
# \ /* \ /
# `-C-' `-*I-*J
#
# A creates "file", B and F change it.
# Odd merge G takes the old version from B.
# I changes it, but J reverts it, so K is TREESAME to both parents.
# H and L both change "file", and M merges those changes.
test_description='TREESAME and limiting'
. ./test-lib.sh
note () {
git tag "$1"
}
unnote () {
git name-rev --tags --stdin | sed -e "s|$_x40 (tags/\([^)]*\))\([ ]\)|\1\2|g"
}
test_expect_success setup '
test_commit "Initial file" file "Hi there" A &&
git branch other-branch &&
test_commit "file=Hello" file "Hello" B &&
git branch third-branch &&
git checkout other-branch &&
test_commit "Added other" other "Hello" C &&
git checkout master &&
test_merge D other-branch &&
git checkout third-branch &&
test_commit "Third file" third "Nothing" E &&
git checkout master &&
test_commit "file=Blah" file "Blah" F &&
test_tick && git merge --no-commit third-branch &&
git checkout third-branch file &&
git commit &&
note G &&
git branch fiddler-branch &&
git checkout -b part2-branch &&
test_commit "file=Part 2" file "Part 2" H &&
git checkout fiddler-branch &&
test_commit "Bad commit" file "Silly" I &&
test_tick && git revert I && note J &&
git checkout master &&
test_tick && git merge --no-ff fiddler-branch &&
note K
test_commit "file=Part 1" file "Part 1" L &&
test_tick && test_must_fail git merge part2-branch &&
test_commit M file "Parts 1+2"
'
check_outcome () {
outcome=$1
shift
case "$1" in
*"("*)
FMT="%P %H | %s"
munge_actual="
s/^\([^ ]*\) \([^ ]*\) .*/(\1)\2/
s/ //g
s/()//
"
;;
*)
FMT="%H | %s"
munge_actual="s/^\([^ ]*\) .*/\1/"
;;
esac &&
printf "%s\n" $1 >expect &&
shift
param="$*" &&
test_expect_$outcome "log $param" '
git log --format="$FMT" $param |
unnote >actual &&
sed -e "$munge_actual" <actual >check &&
test_cmp expect check || {
cat actual
false
}
'
}
check_result () {
check_outcome success "$@"
}
# Odd merge G drops a change in F. Important that G is listed in all
# except the most basic list. Achieving this means normal merge D will also be
# shown in normal full-history, as we can't distinguish unless we do a
# simplification pass. After simplification, D is dropped but G remains.
# Also, merge simplification of G should not drop the parent B that the default
# simple history follows.
check_result 'M L K J I H G F E D C B A'
check_result '(LH)M (K)L (GJ)K (I)J (G)I (G)H (FE)G (D)F (B)E (BC)D (A)C (A)B A'
check_result 'M H L K J I G E F D C B A' --topo-order
check_result 'M L H B A' -- file
check_result '(LH)M (B)L (B)H (A)B A' --parents -- file
check_result 'M L J I H G F D B A' --full-history -- file
check_result '(LH)M (K)L (GJ)K (I)J (G)I (G)H (FB)G (D)F (BA)D (A)B A' --full-history --parents -- file
check_result '(LH)M (G)H (J)L (I)J (G)I (FB)G (B)F (A)B A' --simplify-merges -- file
check_result 'M L K G F D B A' --first-parent
check_result 'M L G F B A' --first-parent -- file
# Check that odd merge G remains shown when F is the bottom.
check_result 'M L K J I H G E' F..M
check_result 'M H L K J I G E' F..M --topo-order
check_result 'M L H' F..M -- file
check_result '(LH)M (B)L (B)H' --parents F..M -- file
check_result 'M L J I H G' F..M --full-history -- file
check_result '(LH)M (K)L (GJ)K (I)J (G)I (G)H (FB)G' F..M --full-history --parents -- file
check_result '(LH)M (G)H (J)L (I)J (G)I (FB)G' F..M --simplify-merges -- file
check_result 'M L K J I H G' F..M --ancestry-path
check_result 'M L J I H G' F..M --ancestry-path -- file
check_result '(LH)M (K)L (GJ)K (I)J (G)I (G)H (FE)G' F..M --ancestry-path --parents -- file
check_result '(LH)M (G)H (J)L (I)J (G)I (FE)G' F..M --ancestry-path --simplify-merges -- file
check_result 'M L K G' F..M --first-parent
check_result 'M L G' F..M --first-parent -- file
# Note that G is pruned when E is the bottom, even if it's the same commit list
# If we want history since E, then we're quite happy to ignore G that took E.
check_result 'M L K J I H G' E..M --ancestry-path
check_result 'M L J I H' E..M --ancestry-path -- file
check_result '(LH)M (K)L (EJ)K (I)J (E)I (E)H' E..M --ancestry-path --parents -- file
check_result '(LH)M (E)H (J)L (I)J (E)I' E..M --ancestry-path --simplify-merges -- file
# Should still be able to ignore I-J branch in simple log, despite limiting
# to G.
check_result 'M L K J I H' G..M
check_result 'M H L K J I' G..M --topo-order
check_result 'M L H' G..M -- file
check_result '(LH)M (G)L (G)H' G..M --parents -- file
check_result 'M L J I H' G..M --full-history -- file
check_result 'M L K J I H' G..M --full-history --parents -- file
check_result 'M H L J I' G..M --simplify-merges -- file
check_result 'M L K J I H' G..M --ancestry-path
check_result 'M L J I H' G..M --ancestry-path -- file
check_result 'M L K J I H' G..M --ancestry-path --parents -- file
check_result 'M H L J I' G..M --ancestry-path --simplify-merges -- file
# B..F should be able to simplify the merge D from irrelevant side branch C.
# Default log should also be free to follow B-D, and ignore C.
# But --full-history shouldn't drop D on its own - without simplification,
# we can't decide if the merge from INTERESTING commit C was sensible.
check_result 'F D C' B..F
check_result 'F' B..F -- file
check_result '(B)F' B..F --parents -- file
check_result 'F D' B..F --full-history -- file
check_result '(D)F (BA)D' B..F --full-history --parents -- file
check_result '(B)F' B..F --simplify-merges -- file
check_result 'F D' B..F --ancestry-path
check_result 'F' B..F --ancestry-path -- file
check_result 'F' B..F --ancestry-path --parents -- file
check_result 'F' B..F --ancestry-path --simplify-merges -- file
check_result 'F D' B..F --first-parent
check_result 'F' B..F --first-parent -- file
# E...F should be equivalent to E F ^B, and be able to drop D as above.
check_result 'F' E F ^B -- file # includes D
check_result 'F' E...F -- file # includes D
# Any sort of full history of C..F should show D, as it's the connection to C,
# and it differs from it.
check_result 'F D B' C..F
check_result 'F B' C..F -- file
check_result '(B)F (A)B' C..F --parents -- file
check_result 'F D B' C..F --full-history -- file
check_result '(D)F (BC)D (A)B' C..F --full-history --parents -- file
check_result '(D)F (BC)D (A)B' C..F --simplify-merges -- file
check_result 'F D' C..F --ancestry-path
check_result 'F D' C..F --ancestry-path -- file
check_result 'F D' C..F --ancestry-path --parents -- file
check_result 'F D' C..F --ancestry-path --simplify-merges -- file
check_result 'F D B' C..F --first-parent
check_result 'F B' C..F --first-parent -- file
test_done