pack-objects: document about thread synchronization
[gitweb.git] / builtin / merge.c
index 23c53a3082b26e8f89f8be1f14985acc491d9907..b00d6f4821e7dc4067997bf515702edcfa413501 100644 (file)
@@ -14,6 +14,7 @@
 #include "run-command.h"
 #include "diff.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "diffcore.h"
 #include "revision.h"
@@ -32,6 +33,9 @@
 #include "gpg-interface.h"
 #include "sequencer.h"
 #include "string-list.h"
+#include "packfile.h"
+#include "tag.h"
+#include "alias.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -70,7 +74,9 @@ static int continue_current_merge;
 static int allow_unrelated_histories;
 static int show_progress = -1;
 static int default_to_upstream = 1;
+static int signoff;
 static const char *sign_commit;
+static int verify_msg = 1;
 
 static struct strategy all_strategy[] = {
        { "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
@@ -209,9 +215,9 @@ static struct option builtin_merge_options[] = {
        OPT_BOOL('e', "edit", &option_edit,
                N_("edit message before committing")),
        OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
-       { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
-               N_("abort if fast-forward is not possible"),
-               PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
+       OPT_SET_INT_F(0, "ff-only", &fast_forward,
+                     N_("abort if fast-forward is not possible"),
+                     FF_ONLY, PARSE_OPT_NONEG),
        OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
        OPT_BOOL(0, "verify-signatures", &verify_signatures,
                N_("verify that the named commit has a valid GPG signature")),
@@ -233,6 +239,8 @@ static struct option builtin_merge_options[] = {
        { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
          N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
        OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
+       OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
+       OPT_BOOL(0, "verify", &verify_msg, N_("verify commit-msg hook")),
        OPT_END()
 };
 
@@ -250,6 +258,7 @@ static int save_state(struct object_id *stash)
        struct child_process cp = CHILD_PROCESS_INIT;
        struct strbuf buffer = STRBUF_INIT;
        const char *argv[] = {"stash", "create", NULL};
+       int rc = -1;
 
        cp.argv = argv;
        cp.out = -1;
@@ -263,14 +272,17 @@ static int save_state(struct object_id *stash)
        if (finish_command(&cp) || len < 0)
                die(_("stash failed"));
        else if (!len)          /* no changes */
-               return -1;
+               goto out;
        strbuf_setlen(&buffer, buffer.len-1);
        if (get_oid(buffer.buf, stash))
                die(_("not a valid object: %s"), buffer.buf);
-       return 0;
+       rc = 0;
+out:
+       strbuf_release(&buffer);
+       return rc;
 }
 
-static void read_empty(unsigned const char *sha1, int verbose)
+static void read_empty(const struct object_id *oid, int verbose)
 {
        int i = 0;
        const char *args[7];
@@ -280,15 +292,15 @@ static void read_empty(unsigned const char *sha1, int verbose)
                args[i++] = "-v";
        args[i++] = "-m";
        args[i++] = "-u";
-       args[i++] = EMPTY_TREE_SHA1_HEX;
-       args[i++] = sha1_to_hex(sha1);
+       args[i++] = empty_tree_oid_hex();
+       args[i++] = oid_to_hex(oid);
        args[i] = NULL;
 
        if (run_command_v_opt(args, RUN_GIT_CMD))
                die(_("read-tree failed"));
 }
 
-static void reset_hard(unsigned const char *sha1, int verbose)
+static void reset_hard(const struct object_id *oid, int verbose)
 {
        int i = 0;
        const char *args[6];
@@ -298,7 +310,7 @@ static void reset_hard(unsigned const char *sha1, int verbose)
                args[i++] = "-v";
        args[i++] = "--reset";
        args[i++] = "-u";
-       args[i++] = sha1_to_hex(sha1);
+       args[i++] = oid_to_hex(oid);
        args[i] = NULL;
 
        if (run_command_v_opt(args, RUN_GIT_CMD))
@@ -314,7 +326,7 @@ static void restore_state(const struct object_id *head,
        if (is_null_oid(stash))
                return;
 
-       reset_hard(head->hash, 1);
+       reset_hard(head, 1);
 
        args[2] = oid_to_hex(stash);
 
@@ -396,14 +408,13 @@ static void finish(struct commit *head_commit,
                        printf(_("No merge message -- not updating HEAD\n"));
                else {
                        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
-                       update_ref(reflog_message.buf, "HEAD",
-                               new_head->hash, head->hash, 0,
-                               UPDATE_REFS_DIE_ON_ERR);
+                       update_ref(reflog_message.buf, "HEAD", new_head, head,
+                                  0, UPDATE_REFS_DIE_ON_ERR);
                        /*
                         * We ignore errors in 'gc --auto', since the
                         * user should see them.
                         */
-                       close_all_packs();
+                       close_all_packs(the_repository->objects);
                        run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
                }
        }
@@ -446,7 +457,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
        if (!remote_head)
                die(_("'%s' does not point to a commit"), remote);
 
-       if (dwim_ref(remote, strlen(remote), branch_head.hash, &found_ref) > 0) {
+       if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
                if (starts_with(found_ref, "refs/heads/")) {
                        strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
                                    oid_to_hex(&branch_head), remote);
@@ -512,7 +523,7 @@ static void merge_name(const char *remote, struct strbuf *msg)
                if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
                        strbuf_addf(msg, "%s\t\t%s '%s'\n",
                                    oid_to_hex(&desc->obj->oid),
-                                   typename(desc->obj->type),
+                                   type_name(desc->obj->type),
                                    remote);
                        goto cleanup;
                }
@@ -559,6 +570,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 
        if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
                show_diffstat = git_config_bool(k, v);
+       else if (!strcmp(k, "merge.verifysignatures"))
+               verify_signatures = git_config_bool(k, v);
        else if (!strcmp(k, "pull.twohead"))
                return git_config_string(&pull_twohead, k, v);
        else if (!strcmp(k, "pull.octopus"))
@@ -566,7 +579,7 @@ static int git_merge_config(const char *k, const char *v, void *cb)
        else if (!strcmp(k, "merge.renormalize"))
                option_renormalize = git_config_bool(k, v);
        else if (!strcmp(k, "merge.ff")) {
-               int boolval = git_config_maybe_bool(k, v);
+               int boolval = git_parse_maybe_bool(v);
                if (0 <= boolval) {
                        fast_forward = boolval ? FF_ALLOW : FF_NO;
                } else if (v && !strcmp(v, "only")) {
@@ -628,7 +641,7 @@ static int read_tree_trivial(struct object_id *common, struct object_id *head,
 
 static void write_tree_trivial(struct object_id *oid)
 {
-       if (write_cache_as_tree(oid->hash, 0, NULL))
+       if (write_cache_as_tree(oid, 0, NULL))
                die(_("git write-tree failed to write a tree"));
 }
 
@@ -636,15 +649,14 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                              struct commit_list *remoteheads,
                              struct commit *head)
 {
-       static struct lock_file lock;
+       struct lock_file lock = LOCK_INIT;
        const char *head_arg = "HEAD";
 
        hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
        refresh_cache(REFRESH_QUIET);
-       if (active_cache_changed &&
-           write_locked_index(&the_index, &lock, COMMIT_LOCK))
+       if (write_locked_index(&the_index, &lock,
+                              COMMIT_LOCK | SKIP_IF_UNCHANGED))
                return error(_("Unable to write index."));
-       rollback_lock_file(&lock);
 
        if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
                int clean, x;
@@ -681,10 +693,9 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                                remoteheads->item, reversed, &result);
                if (clean < 0)
                        exit(128);
-               if (active_cache_changed &&
-                   write_locked_index(&the_index, &lock, COMMIT_LOCK))
+               if (write_locked_index(&the_index, &lock,
+                                      COMMIT_LOCK | SKIP_IF_UNCHANGED))
                        die (_("unable to write %s"), get_index_file());
-               rollback_lock_file(&lock);
                return clean ? 0 : 1;
        } else {
                return try_merge_command(strategy, xopts_nr, xopts,
@@ -766,6 +777,8 @@ static void prepare_to_commit(struct commit_list *remoteheads)
                BUG("the control must not reach here under --squash");
        if (0 < option_edit)
                strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
+       if (signoff)
+               append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
        write_merge_heads(remoteheads);
        write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
        if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
@@ -775,6 +788,12 @@ static void prepare_to_commit(struct commit_list *remoteheads)
                if (launch_editor(git_path_merge_msg(), NULL, NULL))
                        abort_commit(remoteheads, NULL);
        }
+
+       if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
+                                         "commit-msg",
+                                         git_path_merge_msg(), NULL))
+               abort_commit(remoteheads, NULL);
+
        read_merge_msg(&msg);
        strbuf_stripspace(&msg, 0 < option_edit);
        if (!msg.len)
@@ -788,22 +807,21 @@ static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 {
        struct object_id result_tree, result_commit;
        struct commit_list *parents, **pptr = &parents;
-       static struct lock_file lock;
+       struct lock_file lock = LOCK_INIT;
 
        hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
        refresh_cache(REFRESH_QUIET);
-       if (active_cache_changed &&
-           write_locked_index(&the_index, &lock, COMMIT_LOCK))
+       if (write_locked_index(&the_index, &lock,
+                              COMMIT_LOCK | SKIP_IF_UNCHANGED))
                return error(_("Unable to write index."));
-       rollback_lock_file(&lock);
 
        write_tree_trivial(&result_tree);
        printf(_("Wonderful.\n"));
        pptr = commit_list_append(head, pptr);
        pptr = commit_list_append(remoteheads->item, pptr);
        prepare_to_commit(remoteheads);
-       if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
-                       result_commit.hash, NULL, sign_commit))
+       if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
+                       &result_commit, NULL, sign_commit))
                die(_("failed to write commit object"));
        finish(head, remoteheads, &result_commit, "In-index merge");
        drop_save();
@@ -827,8 +845,8 @@ static int finish_automerge(struct commit *head,
                commit_list_insert(head, &parents);
        strbuf_addch(&merge_msg, '\n');
        prepare_to_commit(remoteheads);
-       if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
-                       result_commit.hash, NULL, sign_commit))
+       if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
+                       &result_commit, NULL, sign_commit))
                die(_("failed to write commit object"));
        strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
        finish(head, remoteheads, &result_commit, buf.buf);
@@ -929,6 +947,7 @@ static void write_merge_heads(struct commit_list *remoteheads)
        if (fast_forward == FF_NO)
                strbuf_addstr(&buf, "no-ff");
        write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
+       strbuf_release(&buf);
 }
 
 static void write_merge_state(struct commit_list *remoteheads)
@@ -949,7 +968,7 @@ static int default_edit_option(void)
                return 0;
 
        if (e) {
-               int v = git_config_maybe_bool(name, e);
+               int v = git_parse_maybe_bool(e);
                if (v < 0)
                        die(_("Bad value '%s' in environment '%s'"), e, name);
                return v;
@@ -981,6 +1000,7 @@ static struct commit_list *reduce_parents(struct commit *head_commit,
 
        /* Find what parents to record by checking independent ones. */
        parents = reduce_heads(remoteheads);
+       free_commit_list(remoteheads);
 
        remoteheads = NULL;
        remotes = &remoteheads;
@@ -1105,6 +1125,43 @@ static struct commit_list *collect_parents(struct commit *head_commit,
        return remoteheads;
 }
 
+static int merging_a_throwaway_tag(struct commit *commit)
+{
+       char *tag_ref;
+       struct object_id oid;
+       int is_throwaway_tag = 0;
+
+       /* Are we merging a tag? */
+       if (!merge_remote_util(commit) ||
+           !merge_remote_util(commit)->obj ||
+           merge_remote_util(commit)->obj->type != OBJ_TAG)
+               return is_throwaway_tag;
+
+       /*
+        * Now we know we are merging a tag object.  Are we downstream
+        * and following the tags from upstream?  If so, we must have
+        * the tag object pointed at by "refs/tags/$T" where $T is the
+        * tagname recorded in the tag object.  We want to allow such
+        * a "just to catch up" merge to fast-forward.
+        *
+        * Otherwise, we are playing an integrator's role, making a
+        * merge with a throw-away tag from a contributor with
+        * something like "git pull $contributor $signed_tag".
+        * We want to forbid such a merge from fast-forwarding
+        * by default; otherwise we would not keep the signature
+        * anywhere.
+        */
+       tag_ref = xstrfmt("refs/tags/%s",
+                         ((struct tag *)merge_remote_util(commit)->obj)->tag);
+       if (!read_ref(tag_ref, &oid) &&
+           !oidcmp(&oid, &merge_remote_util(commit)->obj->oid))
+               is_throwaway_tag = 0;
+       else
+               is_throwaway_tag = 1;
+       free(tag_ref);
+       return is_throwaway_tag;
+}
+
 int cmd_merge(int argc, const char **argv, const char *prefix)
 {
        struct object_id result_tree, stash, head_oid;
@@ -1125,7 +1182,7 @@ 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 = branch_to_free = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
+       branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
        if (branch)
                skip_prefix(branch, "refs/heads/", &branch);
        if (!branch || is_null_oid(&head_oid))
@@ -1242,9 +1299,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                if (remoteheads->next)
                        die(_("Can merge only exactly one commit into empty head"));
                remote_head_oid = &remoteheads->item->object.oid;
-               read_empty(remote_head_oid->hash, 0);
-               update_ref("initial pull", "HEAD", remote_head_oid->hash,
-                          NULL, 0, UPDATE_REFS_DIE_ON_ERR);
+               read_empty(remote_head_oid, 0);
+               update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
+                          UPDATE_REFS_DIE_ON_ERR);
                goto done;
        }
 
@@ -1269,7 +1326,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 
                        check_commit_signature(commit, &signature_check);
 
-                       find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
+                       find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
                        switch (signature_check.result) {
                        case 'G':
                                break;
@@ -1302,10 +1359,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                            oid_to_hex(&commit->object.oid));
                setenv(buf.buf, merge_remote_util(commit)->name, 1);
                strbuf_reset(&buf);
-               if (fast_forward != FF_ONLY &&
-                   merge_remote_util(commit) &&
-                   merge_remote_util(commit)->obj &&
-                   merge_remote_util(commit)->obj->type == OBJ_TAG)
+               if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
                        fast_forward = FF_NO;
        }
 
@@ -1339,8 +1393,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                free(list);
        }
 
-       update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.oid.hash,
-                  NULL, 0, UPDATE_REFS_DIE_ON_ERR);
+       update_ref("updating ORIG_HEAD", "ORIG_HEAD",
+                  &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
 
        if (remoteheads && !common) {
                /* No common ancestors found. */
@@ -1354,7 +1408,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                 * If head can reach all the merge then we are up to date.
                 * but first the most common case of merging one remote.
                 */
-               finish_up_to_date(_("Already up-to-date."));
+               finish_up_to_date(_("Already up to date."));
                goto done;
        } else if (fast_forward != FF_NO && !remoteheads->next &&
                        !common->next &&
@@ -1365,9 +1419,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 
                if (verbosity >= 0) {
                        printf(_("Updating %s..%s\n"),
-                              find_unique_abbrev(head_commit->object.oid.hash,
+                              find_unique_abbrev(&head_commit->object.oid,
                                                  DEFAULT_ABBREV),
-                              find_unique_abbrev(remoteheads->item->object.oid.hash,
+                              find_unique_abbrev(&remoteheads->item->object.oid,
                                                  DEFAULT_ABBREV));
                }
                strbuf_addstr(&msg, "Fast-forward");
@@ -1437,7 +1491,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                        }
                }
                if (up_to_date) {
-                       finish_up_to_date(_("Already up-to-date. Yeeah!"));
+                       finish_up_to_date(_("Already up to date. Yeeah!"));
                        goto done;
                }
        }