diff --git a/Documentation/git-rev-list.txt b/Documentation/git-rev-list.txt index 4f145eaba47175e48dd592ffe5018be5cb4cb375..3fa45b81cc6de7b5104d343538c9ad040c208ce1 100644 --- a/Documentation/git-rev-list.txt +++ b/Documentation/git-rev-list.txt @@ -26,6 +26,7 @@ SYNOPSIS [ [\--objects | \--objects-edge] [ \--unpacked ] ] [ \--pretty | \--header ] [ \--bisect ] + [ \--bisect-vars ] [ \--merge ] [ \--reverse ] [ \--walk-reflogs ] @@ -249,6 +250,18 @@ introduces a regression is thus reduced to a binary search: repeatedly generate and test new 'midpoint's until the commit chain is of length one. +--bisect-vars:: + +This calculates the same as `--bisect`, but outputs text ready +to be eval'ed by the shell. These lines will assign the name of +the midpoint revision to the variable `bisect_rev`, and the +expected number of commits to be tested after `bisect_rev` is +tested to `bisect_nr`, the expected number of commits to be +tested if `bisect_rev` turns out to be good to `bisect_good`, +the expected number of commits to be tested if `bisect_rev` +turns out to be bad to `bisect_bad`, and the number of commits +we are bisecting right now to `bisect_all`. + -- Commit Ordering diff --git a/builtin-rev-list.c b/builtin-rev-list.c index 51858e3233a74a2a5cc7e96e7dc5d9786fecc326..f91685a4067630b49e6d9235f29ab8f8060faf66 100644 --- a/builtin-rev-list.c +++ b/builtin-rev-list.c @@ -36,7 +36,8 @@ static const char rev_list_usage[] = " --abbrev=nr | --no-abbrev\n" " --abbrev-commit\n" " special purpose:\n" -" --bisect" +" --bisect\n" +" --bisect-vars" ; static struct rev_info revs; @@ -168,38 +169,273 @@ static void clear_distance(struct commit_list *list) } } -static struct commit_list *find_bisection(struct commit_list *list) +#define DEBUG_BISECT 0 + +static inline int weight(struct commit_list *elem) { - int nr, closest; - struct commit_list *p, *best; + return *((int*)(elem->item->util)); +} - nr = 0; - p = list; - while (p) { - if (!revs.prune_fn || (p->item->object.flags & TREECHANGE)) - nr++; - p = p->next; +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++; } - closest = -1; - best = list; + return count; +} + +static inline int halfway(struct commit_list *p, int distance, int nr) +{ + /* + * Don't short-cut something we are not going to return! + */ + if (revs.prune_fn && !(p->item->object.flags & TREECHANGE)) + 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. + */ + distance *= 2; + switch (distance - 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) { - int distance; + 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); + char *ep, *sp; + + fprintf(stderr, "%c%c%c ", + (flags & TREECHANGE) ? '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)); + + sp = strstr(buf, "\n\n"); + if (sp) { + sp += 2; + for (ep = sp; *ep && *ep != '\n'; ep++) + ; + fprintf(stderr, " %.*s", (int)(ep - sp), sp); + } + fprintf(stderr, "\n"); + } +} +#endif /* DEBUG_BISECT */ + +/* + * 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 *find_bisection(struct commit_list *list, + int *reaches, int *all) +{ + int n, nr, on_list, counted, distance; + struct commit_list *p, *best, *next, *last; + int *weights; + + show_list("bisection 2 entry", 0, 0, list); - if (revs.prune_fn && !(p->item->object.flags & TREECHANGE)) + /* + * 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 (!revs.prune_fn || (flags & TREECHANGE)) + nr++; + on_list++; + } + list = last; + show_list("bisection 2 sorted", 0, nr, list); + + *all = nr; + weights = xcalloc(on_list, sizeof(int*)); + 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 (!revs.prune_fn || (flags & TREECHANGE)) { + 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; + n = weight(p); + if (n != -2) + continue; distance = count_distance(p); clear_distance(list); + weight_set(p, distance); + + /* Does it happen to be at exactly half-way? */ + if (halfway(p, distance, nr)) { + p->next = NULL; + *reaches = distance; + free(weights); + 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 (!revs.prune_fn || (flags & TREECHANGE)) { + 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? */ + distance = weight(p); + if (halfway(p, distance, nr)) { + p->next = NULL; + *reaches = distance; + free(weights); + return p; + } + } + } + + show_list("bisection 2 counted all", counted, nr, list); + + /* Then find the best one */ + counted = -1; + best = list; + for (p = list; p; p = p->next) { + unsigned flags = p->item->object.flags; + + if (revs.prune_fn && !(flags & TREECHANGE)) + continue; + distance = weight(p); if (nr - distance < distance) distance = nr - distance; - if (distance > closest) { + if (distance > counted) { best = p; - closest = distance; + counted = distance; + *reaches = weight(p); } } if (best) best->next = NULL; + free(weights); return best; } @@ -225,6 +461,7 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix) struct commit_list *list; int i; int read_from_stdin = 0; + int bisect_show_vars = 0; git_config(git_default_config); init_revisions(&revs, prefix); @@ -247,6 +484,11 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix) bisect_list = 1; continue; } + if (!strcmp(arg, "--bisect-vars")) { + bisect_list = 1; + bisect_show_vars = 1; + continue; + } if (!strcmp(arg, "--stdin")) { if (read_from_stdin++) die("--stdin given twice?"); @@ -285,8 +527,39 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix) if (revs.tree_objects) mark_edges_uninteresting(revs.commits, &revs, show_edge); - if (bisect_list) - revs.commits = find_bisection(revs.commits); + if (bisect_list) { + int reaches = reaches, all = all; + + revs.commits = find_bisection(revs.commits, &reaches, &all); + if (bisect_show_vars) { + int cnt; + if (!revs.commits) + return 1; + /* + * revs.commits can reach "reaches" commits among + * "all" commits. If it is good, then there are + * (all-reaches) commits left to be bisected. + * On the other hand, if it is bad, then the set + * to bisect is "reaches". + * A bisect set of size N has (N-1) commits further + * to test, as we already know one bad one. + */ + cnt = all-reaches; + if (cnt < reaches) + cnt = reaches; + printf("bisect_rev=%s\n" + "bisect_nr=%d\n" + "bisect_good=%d\n" + "bisect_bad=%d\n" + "bisect_all=%d\n", + sha1_to_hex(revs.commits->item->object.sha1), + cnt - 1, + all - reaches - 1, + reaches - 1, + all); + return 0; + } + } traverse_commit_list(&revs, show_commit, show_object); diff --git a/t/t6002-rev-list-bisect.sh b/t/t6002-rev-list-bisect.sh index 7831e3461c3dd7d332db56e9f5828a27009c9460..fcb33027648b8449cba5869cbe808a4e26ff7f2d 100755 --- a/t/t6002-rev-list-bisect.sh +++ b/t/t6002-rev-list-bisect.sh @@ -163,7 +163,7 @@ test_sequence() # the bisection point is the head - this is the bad point. # -test_output_expect_success "--bisect l5 ^root" 'git-rev-list $_bisect_option l5 ^root' < a && git add a && -git commit -m "Initial commit" a +git commit -m "Initial commit" a && +initial=$(git rev-parse --verify HEAD) ' test_expect_success path-optimization ' @@ -16,4 +17,35 @@ test_expect_success path-optimization ' test $(git-rev-list $commit -- . | wc -l) = 1 ' +test_expect_success 'further setup' ' + git checkout -b side && + echo Irrelevant >c && + git add c && + git commit -m "Side makes an irrelevant commit" && + echo "More Irrelevancy" >c && + git add c && + git commit -m "Side makes another irrelevant commit" && + echo Bye >a && + git add a && + git commit -m "Side touches a" && + side=$(git rev-parse --verify HEAD) && + echo "Yet more Irrelevancy" >c && + git add c && + git commit -m "Side makes yet another irrelevant commit" && + git checkout master && + echo Another >b && + git add b && + git commit -m "Master touches b" && + git merge side && + echo Touched >b && + git add b && + git commit -m "Master touches b again" +' + +test_expect_success 'path optimization 2' ' + ( echo "$side"; echo "$initial" ) >expected && + git rev-list HEAD -- a >actual && + diff -u expected actual +' + test_done