From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Seymour Subject: [PATCH] Modify git-rev-list to linearise the commit history in merge order. Date: Fri, 3 Jun 2005 01:16:38 +1000 Message-ID: <2cfc403205060208161bb06662@mail.gmail.com> References: <20050602151332.29183.qmail@blackcubes.dyndns.org> Reply-To: jon@blackcubes.dyndns.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Cc: Linus Torvalds , Paul Mackerras X-From: git-owner@vger.kernel.org Thu Jun 02 17:17:16 2005 Return-path: Received: from vger.kernel.org ([12.107.209.244]) by ciao.gmane.org with esmtp (Exim 4.43) id 1DdrP7-0005Er-9o for gcvg-git@gmane.org; Thu, 02 Jun 2005 17:14:41 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261152AbVFBPRn (ORCPT ); Thu, 2 Jun 2005 11:17:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261156AbVFBPRm (ORCPT ); Thu, 2 Jun 2005 11:17:42 -0400 Received: from rproxy.gmail.com ([64.233.170.202]:7402 "EHLO rproxy.gmail.com") by vger.kernel.org with ESMTP id S261152AbVFBPQj convert rfc822-to-8bit (ORCPT ); Thu, 2 Jun 2005 11:16:39 -0400 Received: by rproxy.gmail.com with SMTP id i8so246246rne for ; Thu, 02 Jun 2005 08:16:38 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=usQjeyyfyiKAi8nSk8R2/iJq1gcxE5+NmAmkM5EWGktUZ4M/n7eJLrnmN+qWQgSNk1a4RC5ovtubAWY5r1ueApvhFNjtBOk2KNQNZJFr37tR04lWrbQ4p/GHOjgFvAOmxHlfjZ+bOCtChyTz/xujyqC4Hj2ii1dg2mfD/wollic= Received: by 10.38.186.20 with SMTP id j20mr385084rnf; Thu, 02 Jun 2005 08:16:38 -0700 (PDT) Received: by 10.38.104.42 with HTTP; Thu, 2 Jun 2005 08:16:38 -0700 (PDT) To: Git Mailing List In-Reply-To: <20050602151332.29183.qmail@blackcubes.dyndns.org> Content-Disposition: inline Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org [PATCH] Modify git-rev-list to linearise the commit history in merge order. This patch linearises the GIT commit history graph into merge order which is defined by invariants specified in Documentation/git-rev-list.txt. The linearisation produced by this patch is superior in an objective sense to that produced by the existing git-rev-list implementation in that the linearisation produced is guaranteed to have the minimum number of discontinuities, where a discontinuity is defined as an adjacent pair of commits in the output list which are not related in a direct child-parent relationship. A test script, t/t5000-rev-list.sh, includes a test which demonstrates that the linearisation produced by --merge-order has less discontinuities than the linearisation produced by git-rev-list without the --merge-order flag specified. To see this, do the following: cd t ./t5000-rev-list.sh cd trash cat actual-default-order cat actual-merge-order The existing behaviour of git-rev-list is preserved, by default. To obtain the modified behaviour, specify --merge-order or --merge-order --show-breaks on the command line. This version of the patch has been tested on the git repository and also on the linux-2.6 repository and has reasonable performance on both. For more details about this change, refer to Documentation/git-rev-list.txt and http://blackcubes.dyndns.org/epoch/. Signed-off-by: Jon Seymour --- diff --git a/Makefile b/Makefile --- a/Makefile +++ b/Makefile @@ -40,9 +40,9 @@ install: $(PROG) $(SCRIPTS) $(INSTALL) $(PROG) $(SCRIPTS) $(dest)$(bin) LIB_OBJS=read-cache.o sha1_file.o usage.o object.o commit.o tree.o blob.o \ - tag.o delta.o date.o index.o diff-delta.o patch-delta.o + tag.o delta.o date.o index.o diff-delta.o patch-delta.o epoch.o LIB_FILE=libgit.a -LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h +LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h epoch.h LIB_H += strbuf.h LIB_OBJS += strbuf.o @@ -134,6 +134,7 @@ diffcore-pathspec.o : $(LIB_H) diffcore. diffcore-pickaxe.o : $(LIB_H) diffcore.h diffcore-break.o : $(LIB_H) diffcore.h diffcore-order.o : $(LIB_H) diffcore.h +epoch.o: $(LIB_H) test: all $(MAKE) -C t/ all diff --git a/commit.c b/commit.c --- a/commit.c +++ b/commit.c @@ -129,7 +129,7 @@ void free_commit_list(struct commit_list } } -static void insert_by_date(struct commit_list **list, struct commit *item) +void insert_by_date(struct commit_list **list, struct commit *item) { struct commit_list **pp = list; struct commit_list *p; @@ -254,3 +254,25 @@ unsigned long pretty_print_commit(const buf[offset] = '\0'; return offset; } + +struct commit *pop_commit(struct commit_list **stack) +{ + struct commit_list *top = *stack; + struct commit *item = top ? top->item : NULL; + + if (top) { + *stack = top->next; + free(top); + } + return item; +} + +int count_parents(struct commit * commit) +{ + int count = 0; + struct commit_list * parents = commit->parents; + for (count=0;parents; parents=parents->next,count++) + ; + return count; +} + diff --git a/commit.h b/commit.h --- a/commit.h +++ b/commit.h @@ -32,6 +32,8 @@ void free_commit_list(struct commit_list void sort_by_date(struct commit_list **list); +void insert_by_date(struct commit_list **list, struct commit *item); + extern unsigned long pretty_print_commit(const char *msg, unsigned long len, char *buf, unsigned long space); @@ -41,4 +43,7 @@ extern unsigned long pretty_print_commit struct commit *pop_most_recent_commit(struct commit_list **list, unsigned int mark); +struct commit *pop_commit(struct commit_list **stack); + +int count_parents(struct commit * commit); #endif /* COMMIT_H */ diff --git a/epoch.c b/epoch.c new file mode 100644 --- /dev/null +++ b/epoch.c @@ -0,0 +1,454 @@ +/* + * Copyright (c) 2005, Jon Seymour + * + * For more information about epoch theory on which this module is based, + * refer to http://blackcubes.dyndns.org/epoch/. That web page defines + * terms such as "epoch" and "minimal, non-linear epoch" and provides rationales + * for some of the algorithms used here. + * + */ +#include +#include // provides arbitrary precision integers required to accurately represent fractional mass +#include "cache.h" +#include "commit.h" +#include "epoch.h" + +struct fraction { + BIGNUM numerator; + BIGNUM denominator; +}; + +#define HAS_EXACTLY_ONE_PARENT(n) ((n)->parents && !(n)->parents->next) + +static BN_CTX *context = NULL; +static struct fraction *one = NULL; +static struct fraction *zero = NULL; + +static BN_CTX *get_BN_CTX() +{ + if (!context) { + context = BN_CTX_new(); + } + return context; +} + +static struct fraction *new_zero() +{ + struct fraction *result = xmalloc(sizeof(*result)); + BN_init(&result->numerator); + BN_init(&result->denominator); + BN_zero(&result->numerator); + BN_one(&result->denominator); + return result; +} + +static void clear_fraction(struct fraction *fraction) +{ + BN_clear(&fraction->numerator); + BN_clear(&fraction->denominator); +} + +static struct fraction *divide(struct fraction *result, struct fraction *fraction, int divisor) +{ + BIGNUM bn_divisor; + + BN_init(&bn_divisor); + BN_set_word(&bn_divisor, divisor); + + BN_copy(&result->numerator, &fraction->numerator); + BN_mul(&result->denominator, &fraction->denominator, &bn_divisor, get_BN_CTX()); + + BN_clear(&bn_divisor); + return result; +} + +static struct fraction *init_fraction(struct fraction *fraction) +{ + BN_init(&fraction->numerator); + BN_init(&fraction->denominator); + BN_zero(&fraction->numerator); + BN_one(&fraction->denominator); + return fraction; +} + +static struct fraction *get_one() +{ + if (!one) { + one = new_zero(); + BN_one(&one->numerator); + } + return one; +} + +static struct fraction *get_zero() +{ + if (!zero) { + zero = new_zero(); + } + return zero; +} + +static struct fraction *copy(struct fraction *to, struct fraction *from) +{ + BN_copy(&to->numerator, &from->numerator); + BN_copy(&to->denominator, &from->denominator); + return to; +} + +static struct fraction *add(struct fraction *result, struct fraction *left, struct fraction *right) +{ + BIGNUM a, b, gcd; + + BN_init(&a); + BN_init(&b); + BN_init(&gcd); + + BN_mul(&a, &left->numerator, &right->denominator, get_BN_CTX()); + BN_mul(&b, &left->denominator, &right->numerator, get_BN_CTX()); + BN_mul(&result->denominator, &left->denominator, &right->denominator, get_BN_CTX()); + BN_add(&result->numerator, &a, &b); + + BN_gcd(&gcd, &result->denominator, &result->numerator, get_BN_CTX()); + BN_div(&result->denominator, NULL, &result->denominator, &gcd, get_BN_CTX()); + BN_div(&result->numerator, NULL, &result->numerator, &gcd, get_BN_CTX()); + + BN_clear(&a); + BN_clear(&b); + BN_clear(&gcd); + + return result; +} + +static int compare(struct fraction *left, struct fraction *right) +{ + BIGNUM a, b; + + int result; + + BN_init(&a); + BN_init(&b); + + BN_mul(&a, &left->numerator, &right->denominator, get_BN_CTX()); + BN_mul(&b, &left->denominator, &right->numerator, get_BN_CTX()); + + result = BN_cmp(&a, &b); + + BN_clear(&a); + BN_clear(&b); + + return result; +} + +struct mass_counter { + struct fraction seen; + struct fraction pending; +}; + +static struct mass_counter *new_mass_counter(struct commit *commit, struct fraction *pending) +{ + struct mass_counter *mass_counter = xmalloc(sizeof(*mass_counter)); + memset(mass_counter, 0, sizeof(*mass_counter)); + + init_fraction(&mass_counter->seen); + init_fraction(&mass_counter->pending); + + copy(&mass_counter->pending, pending); + copy(&mass_counter->seen, get_zero()); + + commit->object.util = mass_counter; + + return mass_counter; +} + +static void free_mass_counter(struct mass_counter *counter) +{ + clear_fraction(&counter->seen); + clear_fraction(&counter->pending); + free(counter); +} + +// +// Finds the base node of an epoch. +// +// This algorithm uses a conservation of mass approach. +// +// The head starts with a weight of 1 and distributes equal portions +// along each edge to each of its parents. The process continues until +// one node discovers that it has acquired a total mass of 1 from its +// descendents. This node is the base node. +// +// Importantly the queue of nodes to be processed is sorted in +// reverse date order and each node occupies at most one +// position in the queue simultaneously. These two properties +// do not effect the algorithm's correctness. However assuming most, but +// not all, timestamps are sane they do prevent the algorithm becoming +// exponential by ensuring that most nodes are only visited once. +// This is true because mass is only propagated through the network +// when we are pretty sure we are not going to see any more coming +// our way. The occasional bad timestamp will mean that we are +// wrong, occasionally, but this does not matter too much. +// +static int find_base(struct commit *head, struct commit **boundary) +{ + int ret = 0; + + struct commit_list *cleaner = NULL; + struct commit_list *pending = NULL; + + *boundary = NULL; + + // we inject a mass of 1 unit here + + new_mass_counter(head, get_one()); + + commit_list_insert(head, &pending); + commit_list_insert(head, &cleaner); + + while (!*boundary && pending && !ret) { + + struct commit *latest = pop_commit(&pending); + struct mass_counter *latest_node = (struct mass_counter *) latest->object.util; + + if ((ret = parse_commit(latest))) + continue; + + add(&latest_node->seen, &latest_node->seen, &latest_node->pending); + + int num_parents = count_parents(latest); + + if (num_parents) { + + struct fraction distribution; + + divide(init_fraction(&distribution), &latest_node->pending, num_parents); + + struct commit_list *parents; + + for (parents = latest->parents; parents; parents = parents->next) { + struct commit *parent = parents->item; + struct mass_counter *parent_node = (struct mass_counter *) parent->object.util; + if (!parent_node) { + parent_node = new_mass_counter(parent, &distribution); + commit_list_insert(parent, &cleaner); + insert_by_date(&pending, parent); + } else { + if (!compare(&parent_node->pending, get_zero())) { + copy(&parent_node->pending, &distribution); + insert_by_date(&pending, parent); + } else { + add(&parent_node->pending, &parent_node->pending, &distribution); + } + } + } + } + + if (!compare(&latest_node->seen, get_one()) && (latest != head)) { + // if this node has seen one unit of mass, it must be the base, so mark + // the boundary which will cause the loop to stop. + *boundary = latest; + } + + copy(&latest_node->pending, get_zero()); + + } + + for (; cleaner;) { + struct commit *next = pop_commit(&cleaner); + free_mass_counter((struct mass_counter *) next->object.util); + next->object.util = NULL; + } + + if (pending) + free_commit_list(pending); + + return ret; + +} + +// +// This procedure traverses to the boundary of the first epoch in the epoch +// sequence of the epoch headed at head_of_epoch. This is either the end of +// the maximal linear epoch or the base of a minimal non-linear epoch. +// +// The queue of pending nodes is sorted in reverse date order and each node +// is currently in the queue at most once. +// +static int find_next_epoch_boundary(struct commit *head_of_epoch, struct commit **boundary) +{ + int ret; + struct commit *item = head_of_epoch; + + ret = parse_commit(item); + if (ret) + return ret; + + if (HAS_EXACTLY_ONE_PARENT(item)) { + + // we are at the start of a maximimal linear epoch .. traverse to the end + + // traverse to the end of a maximal linear epoch + while (HAS_EXACTLY_ONE_PARENT(item) && !ret) { + item = item->parents->item; + ret = parse_commit(item); + } + *boundary = item; + + } else { + + // otherwise, we are at the start of a minimal, non-linear + // epoch - find the common base of all parents. + + ret = find_base(item, boundary); + + } + + return ret; +} + +// +// Returns non-zero if parent is known to be a parent of child. +// +static int is_parent_of(struct commit *parent, struct commit *child) +{ + struct commit_list *parents; + for (parents = child->parents; parents; parents = parents->next) { + if (!memcmp(parent->object.sha1, parents->item->object.sha1, sizeof(parents->item->object.sha1))) + return 1; + } + return 0; +} + +static void push_onto_merge_order_stack(struct commit_list **stack, struct commit *item) +{ + struct commit_list *top = *stack; + if (top && (top->item->object.flags & MERGE_ORDER_BREAK_FLAG)) { + if (is_parent_of(top->item, item)) { + top->item->object.flags &= ~MERGE_ORDER_BREAK_FLAG; + } + } + commit_list_insert(item, stack); +} + +// +// Sorts the nodes of the first epoch of the epoch sequence of the epoch headed at head +// into merge order. +// +static void sort_first_epoch(struct commit *head, struct commit_list **stack) +{ + parse_commit(head); + + head->object.flags |= MERGE_ORDER_VISIT_FLAG; + + struct commit_list *parents; + + struct commit_list *reversed_parents = NULL; + + // + // parse_commit builds the parent list in reverse order with respect to the order of + // the git-commit-tree arguments. + // + // so we need to reverse this list to output the oldest (or most "local") commits last. + // + + for (parents = head->parents; parents; parents = parents->next) { + commit_list_insert(parents->item, &reversed_parents); + } + + // + // todo: by sorting the parents in a different order, we can alter the + // merge order to show contemporaneous changes in parallel branches + // occurring after "local" changes. This is useful for a developer + // when a developer wants to see all changes that were incorporated + // into the same merge as her own changes occur after her own + // changes. + // + + for (; reversed_parents;) { + struct commit *parent = pop_commit(&reversed_parents); + parse_commit(parent); + if (!(parent->object.flags & MERGE_ORDER_VISIT_FLAG)) { + if (parent->object.flags & MERGE_ORDER_EPOCH_FLAG) { + if (*stack) { + die("something else is on the stack - %s\n", sha1_to_hex((*stack)->item->object.sha1)); + } + push_onto_merge_order_stack(stack, parent); + parent->object.flags |= MERGE_ORDER_VISIT_FLAG; + } else { + sort_first_epoch(parent, stack); + if (reversed_parents) { + // + // this indicates a possible discontinuity + // it may not be be actual discontinuity if + // the head of parent N happens to be the tail + // of parent N+1 + // + // the next push onto the stack will resolve the question + // + (*stack)->item->object.flags |= MERGE_ORDER_BREAK_FLAG; + } + } + } + } + + push_onto_merge_order_stack(stack, head); +} + +// +// Sorts an arbitrary epoch into merge order by sorting each epoch +// of its epoch sequence into order. +// +// Note: this algorithm currently leaves traces of its execution in the +// object flags of nodes it discovers. This should probably be fixed. +// +int sort_in_merge_order(struct commit *head_of_epoch, emitter_func emitter) +{ + struct commit *next; + int ret = 0; + int stop = 0; + + parse_commit(head_of_epoch); + + for (next = head_of_epoch; next && next->parents && !ret && !stop;) { + + struct commit *base = NULL; + + ret = find_next_epoch_boundary(next, &base); + if (ret) + return ret; + + next->object.flags |= MERGE_ORDER_EPOCH_FLAG; + if (base) { + base->object.flags |= MERGE_ORDER_EPOCH_FLAG; + } + + if (HAS_EXACTLY_ONE_PARENT(next)) { + + while (HAS_EXACTLY_ONE_PARENT(next) && !stop && !ret) { + stop = (*emitter) (next); + next = next->parents->item; + ret = parse_commit(next); + } + + } else { + + struct commit_list *stack = NULL; + sort_first_epoch(next, &stack); + for (; stack && !stop;) { + next = pop_commit(&stack); + if (stack) { + stop = (*emitter) (next); + } + } + if (stack) { + free_commit_list(stack); + } + } + + } + + if (next && !stop) { + stop = (*emitter) (next); + } + + return ret; +} diff --git a/epoch.h b/epoch.h new file mode 100644 --- /dev/null +++ b/epoch.h @@ -0,0 +1,12 @@ +#ifndef EPOCH_H +#define EPOCH_H + +typedef int (*emitter_func) (struct commit *); + +int sort_in_merge_order(struct commit *head_of_epoch, emitter_func emitter); + +#define MERGE_ORDER_EPOCH_FLAG (1u<<3) +#define MERGE_ORDER_VISIT_FLAG (1u<<4) +#define MERGE_ORDER_BREAK_FLAG (1u<<5) + +#endif /* EPOCH_H */ diff --git a/object.h b/object.h --- a/object.h +++ b/object.h @@ -15,6 +15,7 @@ struct object { const char *type; struct object_list *refs; struct object_list *attached_deltas; + void *util; }; extern int nr_objs; diff --git a/rev-list.c b/rev-list.c --- a/rev-list.c +++ b/rev-list.c @@ -1,5 +1,6 @@ #include "cache.h" #include "commit.h" +#include "epoch.h" #define SEEN (1u << 0) #define INTERESTING (1u << 1) @@ -11,7 +12,8 @@ static const char rev_list_usage[] = " --max-age=epoch\n" " --min-age=epoch\n" " --header\n" - " --pretty"; + " --pretty\n" + " --merge-order [ --show-breaks ]"; static void mark_parents_uninteresting(struct commit *commit) { @@ -36,18 +38,63 @@ static int everybody_uninteresting(struc return 1; } +static unsigned long max_age = -1; +static unsigned long min_age = -1; +static int max_count = -1; +static int verbose_header = 0, show_parents = 0, pretty_print = 0, merge_order = 0, show_breaks = 0; +static const char *prefix = ""; +static int hdr_termination = 0; + +static int process_commit(struct commit * commit) +{ + if (commit->object.flags & UNINTERESTING) + return 0; + if (min_age != -1 && (commit->date > min_age)) + return 0; + if (max_age != -1 && (commit->date < max_age)) + return 1; + if (max_count != -1 && !max_count--) + return 1; + + if (!show_breaks) { + printf("%s%s", prefix, sha1_to_hex(commit->object.sha1)); + if (show_parents) { + struct commit_list *parents = commit->parents; + while (parents) { + printf(" %s", sha1_to_hex(parents->item->object.sha1)); + parents = parents->next; + } + } + putchar('\n'); + if (verbose_header) { + const char *buf = commit->buffer; + if (pretty_print) { + static char pretty_header[16384]; + pretty_print_commit(commit->buffer, ~0, pretty_header, sizeof(pretty_header)); + buf = pretty_header; + } + printf("%s%c", buf, hdr_termination); + } + } else { + char c='|'; + if (commit->object.flags & MERGE_ORDER_BREAK_FLAG) { + c = '^'; + } else if (commit->object.flags & MERGE_ORDER_EPOCH_FLAG) { + c = '='; + } + printf("%c %s\n", c, sha1_to_hex(commit->object.sha1)); + } + + return 0; +} + int main(int argc, char **argv) { int nr_sha; unsigned char sha1[2][20]; struct commit_list *list = NULL; struct commit *commit, *end; - int i, verbose_header = 0, show_parents = 0, pretty_print = 0; - int hdr_termination = 0; - const char *prefix = ""; - unsigned long max_age = -1; - unsigned long min_age = -1; - int max_count = -1; + int i; nr_sha = 0; for (i = 1 ; i < argc; i++) { @@ -80,8 +127,16 @@ int main(int argc, char **argv) show_parents = 1; continue; } + if (!strncmp(arg, "--merge-order", 13)) { + merge_order = 1; + continue; + } + if (!strncmp(arg, "--show-breaks", 13)) { + show_breaks = 1; + continue; + } - if (nr_sha > 2 || get_sha1(arg, sha1[nr_sha])) + if (nr_sha > 2 || get_sha1(arg, sha1[nr_sha])|| (show_breaks && !merge_order)) usage(rev_list_usage); nr_sha++; } @@ -118,36 +173,19 @@ int main(int argc, char **argv) } while (list); list = newlist; } + + if (!merge_order) { + while (list) { + struct commit *commit = pop_most_recent_commit(&list, SEEN); + if (process_commit(commit)) { + break; + } + } + } else { + if (sort_in_merge_order(commit, &process_commit)) { + die("merge order sort failed\n"); + } + } - while (list) { - struct commit *commit = pop_most_recent_commit(&list, SEEN); - - if (commit->object.flags & UNINTERESTING) - continue; - if (min_age != -1 && (commit->date > min_age)) - continue; - if (max_age != -1 && (commit->date < max_age)) - break; - if (max_count != -1 && !max_count--) - break; - printf("%s%s", prefix, sha1_to_hex(commit->object.sha1)); - if (show_parents) { - struct commit_list *parents = commit->parents; - while (parents) { - printf(" %s", sha1_to_hex(parents->item->object.sha1)); - parents = parents->next; - } - } - putchar('\n'); - if (verbose_header) { - const char *buf = commit->buffer; - if (pretty_print) { - static char pretty_header[16384]; - pretty_print_commit(commit->buffer, ~0, pretty_header, sizeof(pretty_header)); - buf = pretty_header; - } - printf("%s%c", buf, hdr_termination); - } - } return 0; } diff --git a/t/t5000-rev-list.sh b/t/t5000-rev-list.sh new file mode 100755 --- /dev/null +++ b/t/t5000-rev-list.sh @@ -0,0 +1,85 @@ +#!/bin/sh +# +# Copyright (c) 2005 Jon Seymour +# + +test_description='Test rev-list --merge-order +' +. ./test-lib.sh + +function do_commit +{ + git-commit-tree "$@" /dev/null) + then + echo "^ $next" + else + echo "| $next" + fi + previous=$next + done +} + +function sed_script +{ + for c in root a0 a1 a2 a3 a4 b1 b2 b3 b4 c1 c2 c3 + do + echo -n "s/${!c}/$c/;" + done +} + +date >path0 +git-update-cache --add path0 +tree=$(git-write-tree) +root=$(do_commit $tree) +export GIT_COMMITTER_NAME=foobar # to guarantee that the commit is different +a0=$(do_commit $tree -p $root) +a1=$(do_commit $tree -p $a0) +export GIT_COMMITTER_NAME=foobar2 # to guarantee that the commit is different +b1=$(do_commit $tree -p $root) +c1=$(do_commit $tree -p $b1) +export GIT_COMMITTER_NAME=foobar3 # to guarantee that the commit is different +b2=$(do_commit $tree -p $b1) +b3=$(do_commit $tree -p $b2) +c2=$(do_commit $tree -p $c1 -p $b2) +c3=$(do_commit $tree -p $c2) +a2=$(do_commit $tree -p $a1) +a3=$(do_commit $tree -p $a2) +b4=$(do_commit $tree -p $b3 -p $a3) +a4=$(do_commit $tree -p $a3 -p $b4 -p $c3) +echo $a4 > .git/HEAD + +git-rev-list --merge-order --show-breaks HEAD | sed "$(sed_script)" > actual-merge-order +cat > expected-merge-order < actual-default-order +normal_adjacency_count=$(git-rev-list HEAD | check_adjacency | grep -c "\^" | tr -d ' ') +merge_order_adjacency_count=$(git-rev-list --merge-order HEAD | check_adjacency | grep -c "\^" | tr -d ' ') + +test_expect_success 'Testing that the rev-list has correct number of entries' '[ $(git-rev-list HEAD | wc -l) -eq 13 ]' +test_expect_success 'Testing that --merge-order produces the correct result' 'diff expected-merge-order actual-merge-order' +test_expect_success 'Testing that --merge-order produces as many or fewer discontinuities' '[ $merge_order_adjacency_count -le $normal_adjacency_count ]' + +test_done -- homepage: http://www.zeta.org.au/~jon/ blog: http://orwelliantremors.blogspot.com/