git/bisect.c

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#include "cache.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "refs.h"
#include "list-objects.h"
#include "quote.h"
#include "sha1-lookup.h"
#include "run-command.h"
#include "log-tree.h"
#include "bisect.h"
#include "sha1-array.h"
#include "argv-array.h"
static struct sha1_array good_revs;
static struct sha1_array skipped_revs;
static struct object_id *current_bad_oid;
static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
static const char *term_bad;
static const char *term_good;
/* Remember to update object flag allocation in object.h */
#define COUNTED (1u<<16)
/*
* This is a truly stupid algorithm, but it's only
* used for bisection, and we just don't care enough.
*
* We care just barely enough to avoid recursing for
* non-merge entries.
*/
static int count_distance(struct commit_list *entry)
{
int nr = 0;
while (entry) {
struct commit *commit = entry->item;
struct commit_list *p;
if (commit->object.flags & (UNINTERESTING | COUNTED))
break;
if (!(commit->object.flags & TREESAME))
nr++;
commit->object.flags |= COUNTED;
p = commit->parents;
entry = p;
if (p) {
p = p->next;
while (p) {
nr += count_distance(p);
p = p->next;
}
}
}
return nr;
}
static void clear_distance(struct commit_list *list)
{
while (list) {
struct commit *commit = list->item;
commit->object.flags &= ~COUNTED;
list = list->next;
}
}
#define DEBUG_BISECT 0
static inline int weight(struct commit_list *elem)
{
return *((int*)(elem->item->util));
}
static inline void weight_set(struct commit_list *elem, int weight)
{
*((int*)(elem->item->util)) = weight;
}
static int count_interesting_parents(struct commit *commit)
{
struct commit_list *p;
int count;
for (count = 0, p = commit->parents; p; p = p->next) {
if (p->item->object.flags & UNINTERESTING)
continue;
count++;
}
return count;
}
static inline int halfway(struct commit_list *p, int nr)
{
/*
* Don't short-cut something we are not going to return!
*/
if (p->item->object.flags & TREESAME)
return 0;
if (DEBUG_BISECT)
return 0;
/*
* 2 and 3 are halfway of 5.
* 3 is halfway of 6 but 2 and 4 are not.
*/
switch (2 * weight(p) - nr) {
case -1: case 0: case 1:
return 1;
default:
return 0;
}
}
#if !DEBUG_BISECT
#define show_list(a,b,c,d) do { ; } while (0)
#else
static void show_list(const char *debug, int counted, int nr,
struct commit_list *list)
{
struct commit_list *p;
fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
for (p = list; p; p = p->next) {
struct commit_list *pp;
struct commit *commit = p->item;
unsigned flags = commit->object.flags;
enum object_type type;
unsigned long size;
char *buf = read_sha1_file(commit->object.sha1, &type, &size);
const char *subject_start;
int subject_len;
fprintf(stderr, "%c%c%c ",
(flags & TREESAME) ? ' ' : 'T',
(flags & UNINTERESTING) ? 'U' : ' ',
(flags & COUNTED) ? 'C' : ' ');
if (commit->util)
fprintf(stderr, "%3d", weight(p));
else
fprintf(stderr, "---");
fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
for (pp = commit->parents; pp; pp = pp->next)
fprintf(stderr, " %.*s", 8,
sha1_to_hex(pp->item->object.sha1));
subject_len = find_commit_subject(buf, &subject_start);
if (subject_len)
fprintf(stderr, " %.*s", subject_len, subject_start);
fprintf(stderr, "\n");
}
}
#endif /* DEBUG_BISECT */
static struct commit_list *best_bisection(struct commit_list *list, int nr)
{
struct commit_list *p, *best;
int best_distance = -1;
best = list;
for (p = list; p; p = p->next) {
int distance;
unsigned flags = p->item->object.flags;
if (flags & TREESAME)
continue;
distance = weight(p);
if (nr - distance < distance)
distance = nr - distance;
if (distance > best_distance) {
best = p;
best_distance = distance;
}
}
return best;
}
struct commit_dist {
struct commit *commit;
int distance;
};
static int compare_commit_dist(const void *a_, const void *b_)
{
struct commit_dist *a, *b;
a = (struct commit_dist *)a_;
b = (struct commit_dist *)b_;
if (a->distance != b->distance)
return b->distance - a->distance; /* desc sort */
return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
}
static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
{
struct commit_list *p;
struct commit_dist *array = xcalloc(nr, sizeof(*array));
int cnt, i;
for (p = list, cnt = 0; p; p = p->next) {
int distance;
unsigned flags = p->item->object.flags;
if (flags & TREESAME)
continue;
distance = weight(p);
if (nr - distance < distance)
distance = nr - distance;
array[cnt].commit = p->item;
array[cnt].distance = distance;
cnt++;
}
qsort(array, cnt, sizeof(*array), compare_commit_dist);
for (p = list, i = 0; i < cnt; i++) {
char buf[100]; /* enough for dist=%d */
struct object *obj = &(array[i].commit->object);
snprintf(buf, sizeof(buf), "dist=%d", array[i].distance);
add_name_decoration(DECORATION_NONE, buf, obj);
p->item = array[i].commit;
p = p->next;
}
if (p)
p->next = NULL;
free(array);
return list;
}
/*
* zero or positive weight is the number of interesting commits it can
* reach, including itself. Especially, weight = 0 means it does not
* reach any tree-changing commits (e.g. just above uninteresting one
* but traversal is with pathspec).
*
* weight = -1 means it has one parent and its distance is yet to
* be computed.
*
* weight = -2 means it has more than one parent and its distance is
* unknown. After running count_distance() first, they will get zero
* or positive distance.
*/
static struct commit_list *do_find_bisection(struct commit_list *list,
int nr, int *weights,
int find_all)
{
int n, counted;
struct commit_list *p;
counted = 0;
for (n = 0, p = list; p; p = p->next) {
struct commit *commit = p->item;
unsigned flags = commit->object.flags;
p->item->util = &weights[n++];
switch (count_interesting_parents(commit)) {
case 0:
if (!(flags & TREESAME)) {
weight_set(p, 1);
counted++;
show_list("bisection 2 count one",
counted, nr, list);
}
/*
* otherwise, it is known not to reach any
* tree-changing commit and gets weight 0.
*/
break;
case 1:
weight_set(p, -1);
break;
default:
weight_set(p, -2);
break;
}
}
show_list("bisection 2 initialize", counted, nr, list);
/*
* If you have only one parent in the resulting set
* then you can reach one commit more than that parent
* can reach. So we do not have to run the expensive
* count_distance() for single strand of pearls.
*
* However, if you have more than one parents, you cannot
* just add their distance and one for yourself, since
* they usually reach the same ancestor and you would
* end up counting them twice that way.
*
* So we will first count distance of merges the usual
* way, and then fill the blanks using cheaper algorithm.
*/
for (p = list; p; p = p->next) {
if (p->item->object.flags & UNINTERESTING)
continue;
if (weight(p) != -2)
continue;
weight_set(p, count_distance(p));
clear_distance(list);
/* Does it happen to be at exactly half-way? */
if (!find_all && halfway(p, nr))
return p;
counted++;
}
show_list("bisection 2 count_distance", counted, nr, list);
while (counted < nr) {
for (p = list; p; p = p->next) {
struct commit_list *q;
unsigned flags = p->item->object.flags;
if (0 <= weight(p))
continue;
for (q = p->item->parents; q; q = q->next) {
if (q->item->object.flags & UNINTERESTING)
continue;
if (0 <= weight(q))
break;
}
if (!q)
continue;
/*
* weight for p is unknown but q is known.
* add one for p itself if p is to be counted,
* otherwise inherit it from q directly.
*/
if (!(flags & TREESAME)) {
weight_set(p, weight(q)+1);
counted++;
show_list("bisection 2 count one",
counted, nr, list);
}
else
weight_set(p, weight(q));
/* Does it happen to be at exactly half-way? */
if (!find_all && halfway(p, nr))
return p;
}
}
show_list("bisection 2 counted all", counted, nr, list);
if (!find_all)
return best_bisection(list, nr);
else
return best_bisection_sorted(list, nr);
}
struct commit_list *find_bisection(struct commit_list *list,
int *reaches, int *all,
int find_all)
{
int nr, on_list;
struct commit_list *p, *best, *next, *last;
int *weights;
show_list("bisection 2 entry", 0, 0, list);
/*
* Count the number of total and tree-changing items on the
* list, while reversing the list.
*/
for (nr = on_list = 0, last = NULL, p = list;
p;
p = next) {
unsigned flags = p->item->object.flags;
next = p->next;
if (flags & UNINTERESTING)
continue;
p->next = last;
last = p;
if (!(flags & TREESAME))
nr++;
on_list++;
}
list = last;
show_list("bisection 2 sorted", 0, nr, list);
*all = nr;
weights = xcalloc(on_list, sizeof(*weights));
/* Do the real work of finding bisection commit. */
best = do_find_bisection(list, nr, weights, find_all);
if (best) {
if (!find_all)
best->next = NULL;
*reaches = weight(best);
}
free(weights);
return best;
}
static int register_ref(const char *refname, const struct object_id *oid,
int flags, void *cb_data)
{
struct strbuf good_prefix = STRBUF_INIT;
strbuf_addstr(&good_prefix, term_good);
strbuf_addstr(&good_prefix, "-");
if (!strcmp(refname, term_bad)) {
current_bad_oid = xmalloc(sizeof(*current_bad_oid));
oidcpy(current_bad_oid, oid);
} else if (starts_with(refname, good_prefix.buf)) {
sha1_array_append(&good_revs, oid->hash);
} else if (starts_with(refname, "skip-")) {
sha1_array_append(&skipped_revs, oid->hash);
}
strbuf_release(&good_prefix);
return 0;
}
static int read_bisect_refs(void)
{
return for_each_ref_in("refs/bisect/", register_ref, NULL);
}
memoize common git-path "constant" files One of the most common uses of git_path() is to pass a constant, like git_path("MERGE_MSG"). This has two drawbacks: 1. The return value is a static buffer, and the lifetime is dependent on other calls to git_path, etc. 2. There's no compile-time checking of the pathname. This is OK for a one-off (after all, we have to spell it correctly at least once), but many of these constant strings appear throughout the code. This patch introduces a series of functions to "memoize" these strings, which are essentially globals for the lifetime of the program. We compute the value once, take ownership of the buffer, and return the cached value for subsequent calls. cache.h provides a helper macro for defining these functions as one-liners, and defines a few common ones for global use. Using a macro is a little bit gross, but it does nicely document the purpose of the functions. If we need to touch them all later (e.g., because we learned how to change the git_dir variable at runtime, and need to invalidate all of the stored values), it will be much easier to have the complete list. Note that the shared-global functions have separate, manual declarations. We could do something clever with the macros (e.g., expand it to a declaration in some places, and a declaration _and_ a definition in path.c). But there aren't that many, and it's probably better to stay away from too-magical macros. Likewise, if we abandon the C preprocessor in favor of generating these with a script, we could get much fancier. E.g., normalizing "FOO/BAR-BAZ" into "git_path_foo_bar_baz". But the small amount of saved typing is probably not worth the resulting confusion to readers who want to grep for the function's definition. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-10 09:38:57 +00:00
static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
static void read_bisect_paths(struct argv_array *array)
{
struct strbuf str = STRBUF_INIT;
memoize common git-path "constant" files One of the most common uses of git_path() is to pass a constant, like git_path("MERGE_MSG"). This has two drawbacks: 1. The return value is a static buffer, and the lifetime is dependent on other calls to git_path, etc. 2. There's no compile-time checking of the pathname. This is OK for a one-off (after all, we have to spell it correctly at least once), but many of these constant strings appear throughout the code. This patch introduces a series of functions to "memoize" these strings, which are essentially globals for the lifetime of the program. We compute the value once, take ownership of the buffer, and return the cached value for subsequent calls. cache.h provides a helper macro for defining these functions as one-liners, and defines a few common ones for global use. Using a macro is a little bit gross, but it does nicely document the purpose of the functions. If we need to touch them all later (e.g., because we learned how to change the git_dir variable at runtime, and need to invalidate all of the stored values), it will be much easier to have the complete list. Note that the shared-global functions have separate, manual declarations. We could do something clever with the macros (e.g., expand it to a declaration in some places, and a declaration _and_ a definition in path.c). But there aren't that many, and it's probably better to stay away from too-magical macros. Likewise, if we abandon the C preprocessor in favor of generating these with a script, we could get much fancier. E.g., normalizing "FOO/BAR-BAZ" into "git_path_foo_bar_baz". But the small amount of saved typing is probably not worth the resulting confusion to readers who want to grep for the function's definition. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-10 09:38:57 +00:00
const char *filename = git_path_bisect_names();
FILE *fp = fopen(filename, "r");
if (!fp)
die_errno("Could not open file '%s'", filename);
while (strbuf_getline(&str, fp, '\n') != EOF) {
strbuf_trim(&str);
if (sq_dequote_to_argv_array(str.buf, array))
die("Badly quoted content in file '%s': %s",
filename, str.buf);
}
strbuf_release(&str);
fclose(fp);
}
static char *join_sha1_array_hex(struct sha1_array *array, char delim)
{
struct strbuf joined_hexs = STRBUF_INIT;
int i;
for (i = 0; i < array->nr; i++) {
strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
if (i + 1 < array->nr)
strbuf_addch(&joined_hexs, delim);
}
return strbuf_detach(&joined_hexs, NULL);
}
/*
* In this function, passing a not NULL skipped_first is very special.
* It means that we want to know if the first commit in the list is
* skipped because we will want to test a commit away from it if it is
* indeed skipped.
* So if the first commit is skipped, we cannot take the shortcut to
* just "return list" when we find the first non skipped commit, we
* have to return a fully filtered list.
*
* We use (*skipped_first == -1) to mean "it has been found that the
* first commit is not skipped". In this case *skipped_first is set back
* to 0 just before the function returns.
*/
struct commit_list *filter_skipped(struct commit_list *list,
struct commit_list **tried,
int show_all,
int *count,
int *skipped_first)
{
struct commit_list *filtered = NULL, **f = &filtered;
*tried = NULL;
if (skipped_first)
*skipped_first = 0;
if (count)
*count = 0;
if (!skipped_revs.nr)
return list;
while (list) {
struct commit_list *next = list->next;
list->next = NULL;
if (0 <= sha1_array_lookup(&skipped_revs,
list->item->object.sha1)) {
if (skipped_first && !*skipped_first)
*skipped_first = 1;
/* Move current to tried list */
*tried = list;
tried = &list->next;
} else {
if (!show_all) {
if (!skipped_first || !*skipped_first)
return list;
} else if (skipped_first && !*skipped_first) {
/* This means we know it's not skipped */
*skipped_first = -1;
}
/* Move current to filtered list */
*f = list;
f = &list->next;
if (count)
(*count)++;
}
list = next;
}
if (skipped_first && *skipped_first == -1)
*skipped_first = 0;
return filtered;
}
#define PRN_MODULO 32768
/*
* This is a pseudo random number generator based on "man 3 rand".
* It is not used properly because the seed is the argument and it
* is increased by one between each call, but that should not matter
* for this application.
*/
static unsigned get_prn(unsigned count) {
count = count * 1103515245 + 12345;
return (count/65536) % PRN_MODULO;
}
/*
* Custom integer square root from
* http://en.wikipedia.org/wiki/Integer_square_root
*/
static int sqrti(int val)
{
float d, x = val;
if (val == 0)
return 0;
do {
float y = (x + (float)val / x) / 2;
d = (y > x) ? y - x : x - y;
x = y;
} while (d >= 0.5);
return (int)x;
}
static struct commit_list *skip_away(struct commit_list *list, int count)
{
struct commit_list *cur, *previous;
int prn, index, i;
prn = get_prn(count);
index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
cur = list;
previous = NULL;
for (i = 0; cur; cur = cur->next, i++) {
if (i == index) {
if (hashcmp(cur->item->object.sha1, current_bad_oid->hash))
return cur;
if (previous)
return previous;
return list;
}
previous = cur;
}
return list;
}
static struct commit_list *managed_skipped(struct commit_list *list,
struct commit_list **tried)
{
int count, skipped_first;
*tried = NULL;
if (!skipped_revs.nr)
return list;
list = filter_skipped(list, tried, 0, &count, &skipped_first);
if (!skipped_first)
return list;
return skip_away(list, count);
}
static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
const char *bad_format, const char *good_format,
int read_paths)
{
struct argv_array rev_argv = ARGV_ARRAY_INIT;
int i;
init_revisions(revs, prefix);
revs->abbrev = 0;
revs->commit_format = CMIT_FMT_UNSPECIFIED;
/* rev_argv.argv[0] will be ignored by setup_revisions */
argv_array_push(&rev_argv, "bisect_rev_setup");
argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
for (i = 0; i < good_revs.nr; i++)
argv_array_pushf(&rev_argv, good_format,
sha1_to_hex(good_revs.sha1[i]));
argv_array_push(&rev_argv, "--");
if (read_paths)
read_bisect_paths(&rev_argv);
setup_revisions(rev_argv.argc, rev_argv.argv, revs, NULL);
/* XXX leak rev_argv, as "revs" may still be pointing to it */
}
static void bisect_common(struct rev_info *revs)
{
if (prepare_revision_walk(revs))
die("revision walk setup failed");
if (revs->tree_objects)
mark_edges_uninteresting(revs, NULL);
}
static void exit_if_skipped_commits(struct commit_list *tried,
const struct object_id *bad)
{
if (!tried)
return;
printf("There are only 'skip'ped commits left to test.\n"
"The first %s commit could be any of:\n", term_bad);
print_commit_list(tried, "%s\n", "%s\n");
if (bad)
printf("%s\n", oid_to_hex(bad));
printf("We cannot bisect more!\n");
exit(2);
}
static int is_expected_rev(const struct object_id *oid)
{
memoize common git-path "constant" files One of the most common uses of git_path() is to pass a constant, like git_path("MERGE_MSG"). This has two drawbacks: 1. The return value is a static buffer, and the lifetime is dependent on other calls to git_path, etc. 2. There's no compile-time checking of the pathname. This is OK for a one-off (after all, we have to spell it correctly at least once), but many of these constant strings appear throughout the code. This patch introduces a series of functions to "memoize" these strings, which are essentially globals for the lifetime of the program. We compute the value once, take ownership of the buffer, and return the cached value for subsequent calls. cache.h provides a helper macro for defining these functions as one-liners, and defines a few common ones for global use. Using a macro is a little bit gross, but it does nicely document the purpose of the functions. If we need to touch them all later (e.g., because we learned how to change the git_dir variable at runtime, and need to invalidate all of the stored values), it will be much easier to have the complete list. Note that the shared-global functions have separate, manual declarations. We could do something clever with the macros (e.g., expand it to a declaration in some places, and a declaration _and_ a definition in path.c). But there aren't that many, and it's probably better to stay away from too-magical macros. Likewise, if we abandon the C preprocessor in favor of generating these with a script, we could get much fancier. E.g., normalizing "FOO/BAR-BAZ" into "git_path_foo_bar_baz". But the small amount of saved typing is probably not worth the resulting confusion to readers who want to grep for the function's definition. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-10 09:38:57 +00:00
const char *filename = git_path_bisect_expected_rev();
struct stat st;
struct strbuf str = STRBUF_INIT;
FILE *fp;
int res = 0;
if (stat(filename, &st) || !S_ISREG(st.st_mode))
return 0;
fp = fopen(filename, "r");
if (!fp)
return 0;
if (strbuf_getline(&str, fp, '\n') != EOF)
res = !strcmp(str.buf, oid_to_hex(oid));
strbuf_release(&str);
fclose(fp);
return res;
}
static int bisect_checkout(const unsigned char *bisect_rev, int no_checkout)
{
char bisect_rev_hex[GIT_SHA1_HEXSZ + 1];
memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
argv_checkout[2] = bisect_rev_hex;
if (no_checkout) {
update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
} else {
int res;
res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
if (res)
exit(res);
}
argv_show_branch[1] = bisect_rev_hex;
return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
}
static struct commit *get_commit_reference(const unsigned char *sha1)
{
struct commit *r = lookup_commit_reference(sha1);
if (!r)
die("Not a valid commit name %s", sha1_to_hex(sha1));
return r;
}
static struct commit **get_bad_and_good_commits(int *rev_nr)
{
int len = 1 + good_revs.nr;
struct commit **rev = xmalloc(len * sizeof(*rev));
int i, n = 0;
rev[n++] = get_commit_reference(current_bad_oid->hash);
for (i = 0; i < good_revs.nr; i++)
rev[n++] = get_commit_reference(good_revs.sha1[i]);
*rev_nr = n;
return rev;
}
static void handle_bad_merge_base(void)
{
if (is_expected_rev(current_bad_oid)) {
char *bad_hex = oid_to_hex(current_bad_oid);
char *good_hex = join_sha1_array_hex(&good_revs, ' ');
if (!strcmp(term_bad, "bad") && !strcmp(term_good, "good")) {
fprintf(stderr, "The merge base %s is bad.\n"
"This means the bug has been fixed "
"between %s and [%s].\n",
bad_hex, bad_hex, good_hex);
bisect: add the terms old/new When not looking for a regression during a bisect but for a fix or a change in another given property, it can be confusing to use 'good' and 'bad'. This patch introduce `git bisect new` and `git bisect old` as an alternative to 'bad' and good': the commits which have a certain property must be marked as `new` and the ones which do not as `old`. The output will be the first commit after the change in the property. During a new/old bisect session you cannot use bad/good commands and vice-versa. Some commands are still not available for old/new: * git rev-list --bisect does not treat the revs/bisect/new and revs/bisect/old-SHA1 files. Old discussions: - http://thread.gmane.org/gmane.comp.version-control.git/86063 introduced bisect fix unfixed to find fix. - http://thread.gmane.org/gmane.comp.version-control.git/182398 discussion around bisect yes/no or old/new. - http://thread.gmane.org/gmane.comp.version-control.git/199758 last discussion and reviews New discussions: - http://thread.gmane.org/gmane.comp.version-control.git/271320 ( v2 1/7-4/7 ) - http://comments.gmane.org/gmane.comp.version-control.git/271343 ( v2 5/7-7/7 ) Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr> Signed-off-by: Louis Stuber <stuberl@ensimag.grenoble-inp.fr> Signed-off-by: Valentin Duperray <Valentin.Duperray@ensimag.imag.fr> Signed-off-by: Franck Jonas <Franck.Jonas@ensimag.imag.fr> Signed-off-by: Lucien Kong <Lucien.Kong@ensimag.imag.fr> Signed-off-by: Thomas Nguy <Thomas.Nguy@ensimag.imag.fr> Signed-off-by: Huynh Khoi Nguyen Nguyen <Huynh-Khoi-Nguyen.Nguyen@ensimag.imag.fr> Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-29 15:40:33 +00:00
} else if (!strcmp(term_bad, "new") && !strcmp(term_good, "old")) {
fprintf(stderr, "The merge base %s is new.\n"
"The property has changed "
"between %s and [%s].\n",
bad_hex, bad_hex, good_hex);
} else {
fprintf(stderr, "The merge base %s is %s.\n"
"This means the first '%s' commit is "
"between %s and [%s].\n",
bad_hex, term_bad, term_good, bad_hex, good_hex);
}
exit(3);
}
fprintf(stderr, "Some %s revs are not ancestor of the %s rev.\n"
"git bisect cannot work properly in this case.\n"
"Maybe you mistook %s and %s revs?\n",
term_good, term_bad, term_good, term_bad);
exit(1);
}
static void handle_skipped_merge_base(const unsigned char *mb)
{
char *mb_hex = sha1_to_hex(mb);
char *bad_hex = sha1_to_hex(current_bad_oid->hash);
char *good_hex = join_sha1_array_hex(&good_revs, ' ');
warning("the merge base between %s and [%s] "
"must be skipped.\n"
"So we cannot be sure the first %s commit is "
"between %s and %s.\n"
"We continue anyway.",
bad_hex, good_hex, term_bad, mb_hex, bad_hex);
free(good_hex);
}
/*
bisect: add the terms old/new When not looking for a regression during a bisect but for a fix or a change in another given property, it can be confusing to use 'good' and 'bad'. This patch introduce `git bisect new` and `git bisect old` as an alternative to 'bad' and good': the commits which have a certain property must be marked as `new` and the ones which do not as `old`. The output will be the first commit after the change in the property. During a new/old bisect session you cannot use bad/good commands and vice-versa. Some commands are still not available for old/new: * git rev-list --bisect does not treat the revs/bisect/new and revs/bisect/old-SHA1 files. Old discussions: - http://thread.gmane.org/gmane.comp.version-control.git/86063 introduced bisect fix unfixed to find fix. - http://thread.gmane.org/gmane.comp.version-control.git/182398 discussion around bisect yes/no or old/new. - http://thread.gmane.org/gmane.comp.version-control.git/199758 last discussion and reviews New discussions: - http://thread.gmane.org/gmane.comp.version-control.git/271320 ( v2 1/7-4/7 ) - http://comments.gmane.org/gmane.comp.version-control.git/271343 ( v2 5/7-7/7 ) Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr> Signed-off-by: Louis Stuber <stuberl@ensimag.grenoble-inp.fr> Signed-off-by: Valentin Duperray <Valentin.Duperray@ensimag.imag.fr> Signed-off-by: Franck Jonas <Franck.Jonas@ensimag.imag.fr> Signed-off-by: Lucien Kong <Lucien.Kong@ensimag.imag.fr> Signed-off-by: Thomas Nguy <Thomas.Nguy@ensimag.imag.fr> Signed-off-by: Huynh Khoi Nguyen Nguyen <Huynh-Khoi-Nguyen.Nguyen@ensimag.imag.fr> Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-29 15:40:33 +00:00
* "check_merge_bases" checks that merge bases are not "bad" (or "new").
*
bisect: add the terms old/new When not looking for a regression during a bisect but for a fix or a change in another given property, it can be confusing to use 'good' and 'bad'. This patch introduce `git bisect new` and `git bisect old` as an alternative to 'bad' and good': the commits which have a certain property must be marked as `new` and the ones which do not as `old`. The output will be the first commit after the change in the property. During a new/old bisect session you cannot use bad/good commands and vice-versa. Some commands are still not available for old/new: * git rev-list --bisect does not treat the revs/bisect/new and revs/bisect/old-SHA1 files. Old discussions: - http://thread.gmane.org/gmane.comp.version-control.git/86063 introduced bisect fix unfixed to find fix. - http://thread.gmane.org/gmane.comp.version-control.git/182398 discussion around bisect yes/no or old/new. - http://thread.gmane.org/gmane.comp.version-control.git/199758 last discussion and reviews New discussions: - http://thread.gmane.org/gmane.comp.version-control.git/271320 ( v2 1/7-4/7 ) - http://comments.gmane.org/gmane.comp.version-control.git/271343 ( v2 5/7-7/7 ) Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr> Signed-off-by: Louis Stuber <stuberl@ensimag.grenoble-inp.fr> Signed-off-by: Valentin Duperray <Valentin.Duperray@ensimag.imag.fr> Signed-off-by: Franck Jonas <Franck.Jonas@ensimag.imag.fr> Signed-off-by: Lucien Kong <Lucien.Kong@ensimag.imag.fr> Signed-off-by: Thomas Nguy <Thomas.Nguy@ensimag.imag.fr> Signed-off-by: Huynh Khoi Nguyen Nguyen <Huynh-Khoi-Nguyen.Nguyen@ensimag.imag.fr> Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-29 15:40:33 +00:00
* - If one is "bad" (or "new"), it means the user assumed something wrong
* and we must exit with a non 0 error code.
bisect: add the terms old/new When not looking for a regression during a bisect but for a fix or a change in another given property, it can be confusing to use 'good' and 'bad'. This patch introduce `git bisect new` and `git bisect old` as an alternative to 'bad' and good': the commits which have a certain property must be marked as `new` and the ones which do not as `old`. The output will be the first commit after the change in the property. During a new/old bisect session you cannot use bad/good commands and vice-versa. Some commands are still not available for old/new: * git rev-list --bisect does not treat the revs/bisect/new and revs/bisect/old-SHA1 files. Old discussions: - http://thread.gmane.org/gmane.comp.version-control.git/86063 introduced bisect fix unfixed to find fix. - http://thread.gmane.org/gmane.comp.version-control.git/182398 discussion around bisect yes/no or old/new. - http://thread.gmane.org/gmane.comp.version-control.git/199758 last discussion and reviews New discussions: - http://thread.gmane.org/gmane.comp.version-control.git/271320 ( v2 1/7-4/7 ) - http://comments.gmane.org/gmane.comp.version-control.git/271343 ( v2 5/7-7/7 ) Signed-off-by: Antoine Delaite <antoine.delaite@ensimag.grenoble-inp.fr> Signed-off-by: Louis Stuber <stuberl@ensimag.grenoble-inp.fr> Signed-off-by: Valentin Duperray <Valentin.Duperray@ensimag.imag.fr> Signed-off-by: Franck Jonas <Franck.Jonas@ensimag.imag.fr> Signed-off-by: Lucien Kong <Lucien.Kong@ensimag.imag.fr> Signed-off-by: Thomas Nguy <Thomas.Nguy@ensimag.imag.fr> Signed-off-by: Huynh Khoi Nguyen Nguyen <Huynh-Khoi-Nguyen.Nguyen@ensimag.imag.fr> Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-29 15:40:33 +00:00
* - If one is "good" (or "old"), that's good, we have nothing to do.
* - If one is "skipped", we can't know but we should warn.
* - If we don't know, we should check it out and ask the user to test.
*/
static void check_merge_bases(int no_checkout)
{
struct commit_list *result;
int rev_nr;
struct commit **rev = get_bad_and_good_commits(&rev_nr);
result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
for (; result; result = result->next) {
const unsigned char *mb = result->item->object.sha1;
if (!hashcmp(mb, current_bad_oid->hash)) {
handle_bad_merge_base();
} else if (0 <= sha1_array_lookup(&good_revs, mb)) {
continue;
} else if (0 <= sha1_array_lookup(&skipped_revs, mb)) {
handle_skipped_merge_base(mb);
} else {
printf("Bisecting: a merge base must be tested\n");
exit(bisect_checkout(mb, no_checkout));
}
}
free(rev);
free_commit_list(result);
}
static int check_ancestors(const char *prefix)
{
struct rev_info revs;
struct object_array pending_copy;
int res;
bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
/* Save pending objects, so they can be cleaned up later. */
pending_copy = revs.pending;
revs.leak_pending = 1;
/*
* bisect_common calls prepare_revision_walk right away, which
* (together with .leak_pending = 1) makes us the sole owner of
* the list of pending objects.
*/
bisect_common(&revs);
res = (revs.commits != NULL);
/* Clean up objects used, as they will be reused. */
clear_commit_marks_for_object_array(&pending_copy, ALL_REV_FLAGS);
free(pending_copy.objects);
return res;
}
/*
* "check_good_are_ancestors_of_bad" checks that all "good" revs are
* ancestor of the "bad" rev.
*
* If that's not the case, we need to check the merge bases.
* If a merge base must be tested by the user, its source code will be
* checked out to be tested by the user and we will exit.
*/
static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
{
char *filename = git_pathdup("BISECT_ANCESTORS_OK");
struct stat st;
int fd;
if (!current_bad_oid)
die("a %s revision is needed", term_bad);
/* Check if file BISECT_ANCESTORS_OK exists. */
if (!stat(filename, &st) && S_ISREG(st.st_mode))
goto done;
/* Bisecting with no good rev is ok. */
if (good_revs.nr == 0)
goto done;
/* Check if all good revs are ancestor of the bad rev. */
if (check_ancestors(prefix))
check_merge_bases(no_checkout);
/* Create file BISECT_ANCESTORS_OK. */
fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
if (fd < 0)
warning("could not create file '%s': %s",
filename, strerror(errno));
else
close(fd);
done:
free(filename);
}
/*
* This does "git diff-tree --pretty COMMIT" without one fork+exec.
*/
static void show_diff_tree(const char *prefix, struct commit *commit)
{
struct rev_info opt;
/* diff-tree init */
init_revisions(&opt, prefix);
git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
opt.abbrev = 0;
opt.diff = 1;
/* This is what "--pretty" does */
opt.verbose_header = 1;
opt.use_terminator = 0;
opt.commit_format = CMIT_FMT_DEFAULT;
/* diff-tree init */
if (!opt.diffopt.output_format)
opt.diffopt.output_format = DIFF_FORMAT_RAW;
log_tree_commit(&opt, commit);
}
/*
* The terms used for this bisect session are stored in BISECT_TERMS.
* We read them and store them to adapt the messages accordingly.
* Default is bad/good.
*/
void read_bisect_terms(const char **read_bad, const char **read_good)
{
struct strbuf str = STRBUF_INIT;
const char *filename = git_path("BISECT_TERMS");
FILE *fp = fopen(filename, "r");
if (!fp) {
if (errno == ENOENT) {
*read_bad = "bad";
*read_good = "good";
return;
} else {
die("could not read file '%s': %s", filename,
strerror(errno));
}
} else {
strbuf_getline(&str, fp, '\n');
*read_bad = strbuf_detach(&str, NULL);
strbuf_getline(&str, fp, '\n');
*read_good = strbuf_detach(&str, NULL);
}
strbuf_release(&str);
fclose(fp);
}
/*
* We use the convention that exiting with an exit code 10 means that
* the bisection process finished successfully.
* In this case the calling shell script should exit 0.
*
* If no_checkout is non-zero, the bisection process does not
* checkout the trial commit but instead simply updates BISECT_HEAD.
*/
int bisect_next_all(const char *prefix, int no_checkout)
{
struct rev_info revs;
struct commit_list *tried;
int reaches = 0, all = 0, nr, steps;
const unsigned char *bisect_rev;
read_bisect_terms(&term_bad, &term_good);
if (read_bisect_refs())
die("reading bisect refs failed");
check_good_are_ancestors_of_bad(prefix, no_checkout);
bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
revs.limited = 1;
bisect_common(&revs);
revs.commits = find_bisection(revs.commits, &reaches, &all,
!!skipped_revs.nr);
revs.commits = managed_skipped(revs.commits, &tried);
if (!revs.commits) {
/*
* We should exit here only if the "bad"
* commit is also a "skip" commit.
*/
exit_if_skipped_commits(tried, NULL);
printf("%s was both %s and %s\n",
oid_to_hex(current_bad_oid),
term_good,
term_bad);
exit(1);
}
if (!all) {
fprintf(stderr, "No testable commit found.\n"
"Maybe you started with bad path parameters?\n");
exit(4);
}
bisect_rev = revs.commits->item->object.sha1;
if (!hashcmp(bisect_rev, current_bad_oid->hash)) {
exit_if_skipped_commits(tried, current_bad_oid);
printf("%s is the first %s commit\n", sha1_to_hex(bisect_rev),
term_bad);
show_diff_tree(prefix, revs.commits->item);
/* This means the bisection process succeeded. */
exit(10);
}
nr = all - reaches - 1;
steps = estimate_bisect_steps(all);
printf("Bisecting: %d revision%s left to test after this "
"(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
steps, (steps == 1 ? "" : "s"));
return bisect_checkout(bisect_rev, no_checkout);
}
static inline int log2i(int n)
{
int log2 = 0;
for (; n > 1; n >>= 1)
log2++;
return log2;
}
static inline int exp2i(int n)
{
return 1 << n;
}
/*
* Estimate the number of bisect steps left (after the current step)
*
* For any x between 0 included and 2^n excluded, the probability for
* n - 1 steps left looks like:
*
* P(2^n + x) == (2^n - x) / (2^n + x)
*
* and P(2^n + x) < 0.5 means 2^n < 3x
*/
int estimate_bisect_steps(int all)
{
int n, x, e;
if (all < 3)
return 0;
n = log2i(all);
e = exp2i(n);
x = all - e;
return (e < 3 * x) ? n : n - 1;
}