merge: remove global variable head[]

Also kill head_invalid in favor of "head_commit == NULL".

Local variable "head" in cmd_merge() is renamed to "head_sha1" to make
sure I don't miss any access because this variable should not be used
after head_commit is set (use head_commit->object.sha1 instead).

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/merge.c b/builtin/merge.c
index c371484ab6b779d183534a04a57cdb3c190fc9a9..f5eb3f549b3732c894016a83e3108df3b3f46d81 100644 (file)
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -50,7 +50,6 @@ static int fast_forward_only;
 static int allow_trivial = 1, have_message;
 static struct strbuf merge_msg;
 static struct commit_list *remoteheads;
-static unsigned char head[20];
 static struct strategy **use_strategies;
 static size_t use_strategies_nr, use_strategies_alloc;
 static const char **xopts;
@@ -279,7 +278,8 @@ static void reset_hard(unsigned const char *sha1, int verbose)
                die(_("read-tree failed"));
 }
 
-static void restore_state(const unsigned char *stash)
+static void restore_state(const unsigned char *head,
+                         const unsigned char *stash)
 {
        struct strbuf sb = STRBUF_INIT;
        const char *args[] = { "stash", "apply", NULL, NULL };
@@ -309,10 +309,9 @@ static void finish_up_to_date(const char *msg)
        drop_save();
 }
 
-static void squash_message(void)
+static void squash_message(struct commit *commit)
 {
        struct rev_info rev;
-       struct commit *commit;
        struct strbuf out = STRBUF_INIT;
        struct commit_list *j;
        int fd;
@@ -327,7 +326,6 @@ static void squash_message(void)
        rev.ignore_merges = 1;
        rev.commit_format = CMIT_FMT_MEDIUM;
 
-       commit = lookup_commit(head);
        commit->object.flags |= UNINTERESTING;
        add_pending_object(&rev, &commit->object, NULL);
 
@@ -356,9 +354,11 @@ static void squash_message(void)
        strbuf_release(&out);
 }
 
-static void finish(const unsigned char *new_head, const char *msg)
+static void finish(struct commit *head_commit,
+                  const unsigned char *new_head, const char *msg)
 {
        struct strbuf reflog_message = STRBUF_INIT;
+       const unsigned char *head = head_commit->object.sha1;
 
        if (!msg)
                strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
@@ -369,7 +369,7 @@ static void finish(const unsigned char *new_head, const char *msg)
                        getenv("GIT_REFLOG_ACTION"), msg);
        }
        if (squash) {
-               squash_message();
+               squash_message(head_commit);
        } else {
                if (verbosity >= 0 && !merge_msg.len)
                        printf(_("No merge message -- not updating HEAD\n"));
@@ -664,7 +664,7 @@ int try_merge_command(const char *strategy, size_t xopts_nr,
 }
 
 static int try_merge_strategy(const char *strategy, struct commit_list *common,
-                             const char *head_arg)
+                             struct commit *head, const char *head_arg)
 {
        int index_fd;
        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
@@ -710,7 +710,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                        commit_list_insert(j->item, &reversed);
 
                index_fd = hold_locked_index(lock, 1);
-               clean = merge_recursive(&o, lookup_commit(head),
+               clean = merge_recursive(&o, head,
                                remoteheads->item, reversed, &result);
                if (active_cache_changed &&
                                (write_cache(index_fd, active_cache, active_nr) ||
@@ -861,25 +861,26 @@ static void run_prepare_commit_msg(void)
        read_merge_msg();
 }
 
-static int merge_trivial(void)
+static int merge_trivial(struct commit *head)
 {
        unsigned char result_tree[20], result_commit[20];
        struct commit_list *parent = xmalloc(sizeof(*parent));
 
        write_tree_trivial(result_tree);
        printf(_("Wonderful.\n"));
-       parent->item = lookup_commit(head);
+       parent->item = head;
        parent->next = xmalloc(sizeof(*parent->next));
        parent->next->item = remoteheads->item;
        parent->next->next = NULL;
        run_prepare_commit_msg();
        commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
-       finish(result_commit, "In-index merge");
+       finish(head, result_commit, "In-index merge");
        drop_save();
        return 0;
 }
 
-static int finish_automerge(struct commit_list *common,
+static int finish_automerge(struct commit *head,
+                           struct commit_list *common,
                            unsigned char *result_tree,
                            const char *wt_strategy)
 {
@@ -890,12 +891,12 @@ static int finish_automerge(struct commit_list *common,
        free_commit_list(common);
        if (allow_fast_forward) {
                parents = remoteheads;
-               commit_list_insert(lookup_commit(head), &parents);
+               commit_list_insert(head, &parents);
                parents = reduce_heads(parents);
        } else {
                struct commit_list **pptr = &parents;
 
-               pptr = &commit_list_insert(lookup_commit(head),
+               pptr = &commit_list_insert(head,
                                pptr)->next;
                for (j = remoteheads; j; j = j->next)
                        pptr = &commit_list_insert(j->item, pptr)->next;
@@ -905,7 +906,7 @@ static int finish_automerge(struct commit_list *common,
        run_prepare_commit_msg();
        commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
        strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
-       finish(result_commit, buf.buf);
+       finish(head, result_commit, buf.buf);
        strbuf_release(&buf);
        drop_save();
        return 0;
@@ -939,7 +940,8 @@ static int suggest_conflicts(int renormalizing)
        return 1;
 }
 
-static struct commit *is_old_style_invocation(int argc, const char **argv)
+static struct commit *is_old_style_invocation(int argc, const char **argv,
+                                             const unsigned char *head)
 {
        struct commit *second_token = NULL;
        if (argc > 2) {
@@ -1012,9 +1014,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 {
        unsigned char result_tree[20];
        unsigned char stash[20];
+       unsigned char head_sha1[20];
+       struct commit *head_commit;
        struct strbuf buf = STRBUF_INIT;
        const char *head_arg;
-       int flag, head_invalid = 0, i;
+       int flag, i;
        int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
        struct commit_list *common = NULL;
        const char *best_strategy = NULL, *wt_strategy = NULL;
@@ -1027,11 +1031,16 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * Check if we are _not_ on a detached HEAD, i.e. if there is a
         * current branch.
         */
-       branch = resolve_ref("HEAD", head, 0, &flag);
+       branch = resolve_ref("HEAD", head_sha1, 0, &flag);
        if (branch && !prefixcmp(branch, "refs/heads/"))
                branch += 11;
-       if (!branch || is_null_sha1(head))
-               head_invalid = 1;
+       if (!branch || is_null_sha1(head_sha1))
+               head_commit = NULL;
+       else {
+               head_commit = lookup_commit(head_sha1);
+               if (!head_commit)
+                       die(_("could not parse HEAD"));
+       }
 
        git_config(git_merge_config, NULL);
 
@@ -1112,12 +1121,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * additional safety measure to check for it.
         */
 
-       if (!have_message && is_old_style_invocation(argc, argv)) {
+       if (!have_message && head_commit &&
+           is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
                strbuf_addstr(&merge_msg, argv[0]);
                head_arg = argv[1];
                argv += 2;
                argc -= 2;
-       } else if (head_invalid) {
+       } else if (!head_commit) {
                struct object *remote_head;
                /*
                 * If the merged head is a valid one there is no reason
@@ -1164,7 +1174,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                }
        }
 
-       if (head_invalid || !argc)
+       if (!head_commit || !argc)
                usage_with_options(builtin_merge_usage,
                        builtin_merge_options);
 
@@ -1205,17 +1215,16 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        }
 
        if (!remoteheads->next)
-               common = get_merge_bases(lookup_commit(head),
-                               remoteheads->item, 1);
+               common = get_merge_bases(head_commit, remoteheads->item, 1);
        else {
                struct commit_list *list = remoteheads;
-               commit_list_insert(lookup_commit(head), &list);
+               commit_list_insert(head_commit, &list);
                common = get_octopus_merge_bases(list);
                free(list);
        }
 
-       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
-               DIE_ON_ERR);
+       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
+                  NULL, 0, DIE_ON_ERR);
 
        if (!common)
                ; /* No common ancestors found. We need a real merge. */
@@ -1229,13 +1238,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                return 0;
        } else if (allow_fast_forward && !remoteheads->next &&
                        !common->next &&
-                       !hashcmp(common->item->object.sha1, head)) {
+                       !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
                /* Again the most common case of merging one remote. */
                struct strbuf msg = STRBUF_INIT;
                struct object *o;
                char hex[41];
 
-               strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
+               strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
 
                if (verbosity >= 0)
                        printf(_("Updating %s..%s\n"),
@@ -1251,10 +1260,10 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                if (!o)
                        return 1;
 
-               if (checkout_fast_forward(head, remoteheads->item->object.sha1))
+               if (checkout_fast_forward(head_commit->object.sha1, remoteheads->item->object.sha1))
                        return 1;
 
-               finish(o->sha1, msg.buf);
+               finish(head_commit, o->sha1, msg.buf);
                drop_save();
                return 0;
        } else if (!remoteheads->next && common->next)
@@ -1274,8 +1283,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        git_committer_info(IDENT_ERROR_ON_NO_NAME);
                        printf(_("Trying really trivial in-index merge...\n"));
                        if (!read_tree_trivial(common->item->object.sha1,
-                                       head, remoteheads->item->object.sha1))
-                               return merge_trivial();
+                                       head_commit->object.sha1, remoteheads->item->object.sha1))
+                               return merge_trivial(head_commit);
                        printf(_("Nope.\n"));
                }
        } else {
@@ -1294,8 +1303,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                         * merge_bases again, otherwise "git merge HEAD^
                         * HEAD^^" would be missed.
                         */
-                       common_one = get_merge_bases(lookup_commit(head),
-                               j->item, 1);
+                       common_one = get_merge_bases(head_commit, j->item, 1);
                        if (hashcmp(common_one->item->object.sha1,
                                j->item->object.sha1)) {
                                up_to_date = 0;
@@ -1333,7 +1341,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                int ret;
                if (i) {
                        printf(_("Rewinding the tree to pristine...\n"));
-                       restore_state(stash);
+                       restore_state(head_commit->object.sha1, stash);
                }
                if (use_strategies_nr != 1)
                        printf(_("Trying merge strategy %s...\n"),
@@ -1345,7 +1353,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                wt_strategy = use_strategies[i]->name;
 
                ret = try_merge_strategy(use_strategies[i]->name,
-                       common, head_arg);
+                                        common, head_commit, head_arg);
                if (!option_commit && !ret) {
                        merge_was_ok = 1;
                        /*
@@ -1387,14 +1395,15 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
         * auto resolved the merge cleanly.
         */
        if (automerge_was_ok)
-               return finish_automerge(common, result_tree, wt_strategy);
+               return finish_automerge(head_commit, common, result_tree,
+                                       wt_strategy);
 
        /*
         * Pick the result from the best strategy and have the user fix
         * it up.
         */
        if (!best_strategy) {
-               restore_state(stash);
+               restore_state(head_commit->object.sha1, stash);
                if (use_strategies_nr > 1)
                        fprintf(stderr,
                                _("No merge strategy handled the merge.\n"));
@@ -1406,14 +1415,14 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                ; /* We already have its result in the working tree. */
        else {
                printf(_("Rewinding the tree to pristine...\n"));
-               restore_state(stash);
+               restore_state(head_commit->object.sha1, stash);
                printf(_("Using the %s to prepare resolving by hand.\n"),
                        best_strategy);
-               try_merge_strategy(best_strategy, common, head_arg);
+               try_merge_strategy(best_strategy, common, head_commit, head_arg);
        }
 
        if (squash)
-               finish(NULL, NULL);
+               finish(head_commit, NULL, NULL);
        else {
                int fd;
                struct commit_list *j;