Merge branch 'pt/am-builtin-abort-fix'

"git am" that was recently reimplemented in C had a performance
regression in "git am --abort" that goes back to the version before
an attempted (and failed) patch application.

* pt/am-builtin-abort-fix:
am --skip/--abort: merge HEAD/ORIG_HEAD tree into index

diff --combined builtin/am.c
index b9c62e3de37bbb76e80a21a6e5e5760e1ba04360,3e7e66f82d2598bc4c4a540581b12c1c4a2ff5a1..5d3469609795ac0ce9a718ce38250f9571bb107d
--- 1/builtin/am.c
--- 2/builtin/am.c
+++ b/builtin/am.c
@@@ -10,7 -10,6 +10,7 @@@
  #include "dir.h"
  #include "run-command.h"
  #include "quote.h"
 +#include "tempfile.h"
  #include "lockfile.h"
  #include "cache-tree.h"
  #include "refs.h"
@@@ -99,12 -98,6 +99,12 @@@ enum scissors_type 
        SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
  };
  
 +enum signoff_type {
 +      SIGNOFF_FALSE = 0,
 +      SIGNOFF_TRUE = 1,
 +      SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
 +};
 +
  struct am_state {
        /* state directory path */
        char *dir;
@@@ -130,7 -123,7 +130,7 @@@
        int interactive;
        int threeway;
        int quiet;
 -      int signoff;
 +      int signoff; /* enum signoff_type */
        int utf8;
        int keep; /* enum keep_type */
        int message_id;
@@@ -1192,18 -1185,6 +1192,18 @@@ static void NORETURN die_user_resolve(c
        exit(128);
  }
  
 +/**
 + * Appends signoff to the "msg" field of the am_state.
 + */
 +static void am_append_signoff(struct am_state *state)
 +{
 +      struct strbuf sb = STRBUF_INIT;
 +
 +      strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
 +      append_signoff(&sb, 0, 0);
 +      state->msg = strbuf_detach(&sb, &state->msg_len);
 +}
 +
  /**
   * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
   * state->msg will be set to the patch message. state->author_name,
@@@ -1798,6 -1779,7 +1798,6 @@@ static void am_run(struct am_state *sta
  
                if (resume) {
                        validate_resume_state(state);
 -                      resume = 0;
                } else {
                        int skip;
  
@@@ -1859,10 -1841,6 +1859,10 @@@
  
  next:
                am_next(state);
 +
 +              if (resume)
 +                      am_load(state);
 +              resume = 0;
        }
  
        if (!is_empty_file(am_path(state, "rewritten"))) {
@@@ -1917,7 -1895,6 +1917,7 @@@ static void am_resolve(struct am_state 
  
  next:
        am_next(state);
 +      am_load(state);
        am_run(state, 0);
  }
  
@@@ -1962,16 -1939,49 +1962,49 @@@ static int fast_forward_to(struct tree 
        return 0;
  }
  
+ /**
+  * Merges a tree into the index. The index's stat info will take precedence
+  * over the merged tree's. Returns 0 on success, -1 on failure.
+  */
+ static int merge_tree(struct tree *tree)
+ {
+       struct lock_file *lock_file;
+       struct unpack_trees_options opts;
+       struct tree_desc t[1];
+ 
+       if (parse_tree(tree))
+               return -1;
+ 
+       lock_file = xcalloc(1, sizeof(struct lock_file));
+       hold_locked_index(lock_file, 1);
+ 
+       memset(&opts, 0, sizeof(opts));
+       opts.head_idx = 1;
+       opts.src_index = &the_index;
+       opts.dst_index = &the_index;
+       opts.merge = 1;
+       opts.fn = oneway_merge;
+       init_tree_desc(&t[0], tree->buffer, tree->size);
+ 
+       if (unpack_trees(1, t, &opts)) {
+               rollback_lock_file(lock_file);
+               return -1;
+       }
+ 
+       if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+               die(_("unable to write new index file"));
+ 
+       return 0;
+ }
+ 
  /**
   * Clean the index without touching entries that are not modified between
   * `head` and `remote`.
   */
  static int clean_index(const unsigned char *head, const unsigned char *remote)
  {
-       struct lock_file *lock_file;
        struct tree *head_tree, *remote_tree, *index_tree;
        unsigned char index[GIT_SHA1_RAWSZ];
-       struct pathspec pathspec;
  
        head_tree = parse_tree_indirect(head);
        if (!head_tree)
@@@ -1996,18 -2006,8 +2029,8 @@@
        if (fast_forward_to(index_tree, remote_tree, 0))
                return -1;
  
-       memset(&pathspec, 0, sizeof(pathspec));
- 
-       lock_file = xcalloc(1, sizeof(struct lock_file));
-       hold_locked_index(lock_file, 1);
- 
-       if (read_tree(remote_tree, 0, &pathspec)) {
-               rollback_lock_file(lock_file);
+       if (merge_tree(remote_tree))
                return -1;
-       }
- 
-       if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
-               die(_("unable to write new index file"));
  
        remove_branch_state();
  
@@@ -2045,7 -2045,6 +2068,7 @@@ static void am_skip(struct am_state *st
                die(_("failed to clean index"));
  
        am_next(state);
 +      am_load(state);
        am_run(state, 0);
  }
  
@@@ -2156,7 -2155,6 +2179,7 @@@ int cmd_am(int argc, const char **argv
        int keep_cr = -1;
        int patch_format = PATCH_FORMAT_UNKNOWN;
        enum resume_mode resume = RESUME_FALSE;
 +      int in_progress;
  
        const char * const usage[] = {
                N_("git am [options] [(<mbox>|<Maildir>)...]"),
@@@ -2172,9 -2170,8 +2195,9 @@@
                OPT_BOOL('3', "3way", &state.threeway,
                        N_("allow fall back on 3way merging if needed")),
                OPT__QUIET(&state.quiet, N_("be quiet")),
 -              OPT_BOOL('s', "signoff", &state.signoff,
 -                      N_("add a Signed-off-by line to the commit message")),
 +              OPT_SET_INT('s', "signoff", &state.signoff,
 +                      N_("add a Signed-off-by line to the commit message"),
 +                      SIGNOFF_EXPLICIT),
                OPT_BOOL('u', "utf8", &state.utf8,
                        N_("recode into utf8 (default)")),
                OPT_SET_INT('k', "keep", &state.keep,
@@@ -2253,10 -2250,6 +2276,10 @@@
  
        am_state_init(&state, git_path("rebase-apply"));
  
 +      in_progress = am_in_progress(&state);
 +      if (in_progress)
 +              am_load(&state);
 +
        argc = parse_options(argc, argv, prefix, options, usage, 0);
  
        if (binary >= 0)
@@@ -2269,7 -2262,7 +2292,7 @@@
        if (read_index_preload(&the_index, NULL) < 0)
                die(_("failed to read the index"));
  
 -      if (am_in_progress(&state)) {
 +      if (in_progress) {
                /*
                 * Catch user error to feed us patches when there is a session
                 * in progress:
@@@ -2288,8 -2281,7 +2311,8 @@@
                if (resume == RESUME_FALSE)
                        resume = RESUME_APPLY;
  
 -              am_load(&state);
 +              if (state.signoff == SIGNOFF_EXPLICIT)
 +                      am_append_signoff(&state);
        } else {
                struct argv_array paths = ARGV_ARRAY_INIT;
                int i;