Merge branch 'jc/unresolve' into next

* jc/unresolve:
  Add git-unresolve <paths>...
  get_tree_entry(): make it available from tree-walk
  sha1_name.c: no need to include diff.h; tree-walk.h will do.
  sha1_name.c: prepare to make get_tree_entry() reusable from others.
  pre-commit hook: complain about conflict markers.
  git-merge: a bit more readable user guidance.
  diff: move diff.c to diff-lib.c to make room.
  git log: don't do merge diffs by default
  Allow "git repack" users to specify repacking window/depth

11 files changed, 215 insertions, 63 deletions

diff --git a/.gitignore b/.gitignore
index 145f8555ad..a536f32497 100644
--- a/.gitignore
+++ b/.gitignore
@@ -111,6 +111,7 @@ git-tag
 git-tar-tree
 git-unpack-file
 git-unpack-objects
+git-unresolve
 git-update-index
 git-update-ref
 git-update-server-info
diff --git a/Makefile b/Makefile
index f0be83b296..858e58ddd2 100644
--- a/Makefile
+++ b/Makefile
@@ -165,7 +165,8 @@ PROGRAMS = \
 	git-upload-pack$X git-verify-pack$X git-write-tree$X \
 	git-update-ref$X git-symbolic-ref$X git-check-ref-format$X \
 	git-name-rev$X git-pack-redundant$X git-repo-config$X git-var$X \
-	git-describe$X git-merge-tree$X git-blame$X git-imap-send$X
+	git-describe$X git-merge-tree$X git-blame$X git-imap-send$X \
+	git-unresolve$X
 
 BUILT_INS = git-log$X
 
@@ -199,7 +200,7 @@ LIB_H = \
 	tree-walk.h log-tree.h
 
 DIFF_OBJS = \
-	diff.o diffcore-break.o diffcore-order.o \
+	diff-lib.o diffcore-break.o diffcore-order.o \
 	diffcore-pickaxe.o diffcore-rename.o tree-diff.o combine-diff.o \
 	diffcore-delta.o log-tree.o
 
diff --git a/diff.c b/diff-lib.c
index 0a832c3585..0a832c3585 100644
--- a/diff.c
+++ b/diff-lib.c
diff --git a/git-merge.sh b/git-merge.sh
index 78ab422e4e..b834e79c98 100755
--- a/git-merge.sh
+++ b/git-merge.sh
@@ -335,5 +335,5 @@ Conflicts:
 	then
 		git-rerere
 	fi
-	die "Automatic merge failed; fix up by hand"
+	die "Automatic merge failed; fix conflicts and then commit the result."
 fi
diff --git a/git-repack.sh b/git-repack.sh
index a5d349fd09..e0c9f323c3 100755
--- a/git-repack.sh
+++ b/git-repack.sh
@@ -5,9 +5,9 @@
 
 USAGE='[-a] [-d] [-f] [-l] [-n] [-q]'
 . git-sh-setup
-	
+
 no_update_info= all_into_one= remove_redundant=
-local= quiet= no_reuse_delta=
+local= quiet= no_reuse_delta= extra=
 while case "$#" in 0) break ;; esac
 do
 	case "$1" in
@@ -17,6 +17,8 @@ do
 	-q)	quiet=-q ;;
 	-f)	no_reuse_delta=--no-reuse-delta ;;
 	-l)	local=--local ;;
+	--window=*) extra="$extra $1" ;;
+	--depth=*) extra="$extra $1" ;;
 	*)	usage ;;
 	esac
 	shift
@@ -40,7 +42,7 @@ case ",$all_into_one," in
 	    find . -type f \( -name '*.pack' -o -name '*.idx' \) -print`
 	;;
 esac
-pack_objects="$pack_objects $local $quiet $no_reuse_delta"
+pack_objects="$pack_objects $local $quiet $no_reuse_delta$extra"
 name=$(git-rev-list --objects --all $rev_list 2>&1 |
 	git-pack-objects --non-empty $pack_objects .tmp-pack) ||
 	exit 1
diff --git a/git.c b/git.c
index 0c40773a87..447d86cd57 100644
--- a/git.c
+++ b/git.c
@@ -368,8 +368,6 @@ static int cmd_log(int argc, const char **argv, char **envp)
 	init_revisions(&rev);
 	rev.always_show_header = 1;
 	rev.diffopt.recursive = 1;
-	rev.combine_merges = 1;
-	rev.ignore_merges = 0;
 	return cmd_log_wc(argc, argv, envp, &rev);
 }
 
diff --git a/sha1_name.c b/sha1_name.c
index 0cd1139e06..345935bb2b 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -3,7 +3,7 @@
 #include "commit.h"
 #include "tree.h"
 #include "blob.h"
-#include "diff.h"
+#include "tree-walk.h"
 
 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 {
@@ -450,59 +450,6 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 	return get_short_sha1(name, len, sha1, 0);
 }
 
-static int get_tree_entry(const unsigned char *, const char *, unsigned char *);
-
-static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result)
-{
-	int namelen = strlen(name);
-	while (t->size) {
-		const char *entry;
-		const unsigned char *sha1;
-		int entrylen, cmp;
-		unsigned mode;
-
-		sha1 = tree_entry_extract(t, &entry, &mode);
-		update_tree_entry(t);
-		entrylen = strlen(entry);
-		if (entrylen > namelen)
-			continue;
-		cmp = memcmp(name, entry, entrylen);
-		if (cmp > 0)
-			continue;
-		if (cmp < 0)
-			break;
-		if (entrylen == namelen) {
-			memcpy(result, sha1, 20);
-			return 0;
-		}
-		if (name[entrylen] != '/')
-			continue;
-		if (!S_ISDIR(mode))
-			break;
-		if (++entrylen == namelen) {
-			memcpy(result, sha1, 20);
-			return 0;
-		}
-		return get_tree_entry(sha1, name + entrylen, result);
-	}
-	return -1;
-}
-
-static int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1)
-{
-	int retval;
-	void *tree;
-	struct tree_desc t;
-
-	tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
-	if (!tree)
-		return -1;
-	t.buf = tree;
-	retval = find_tree_entry(&t, name, sha1);
-	free(tree);
-	return retval;
-}
-
 /*
  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
  * notably "xyz^" for "parent of xyz"
@@ -510,6 +457,7 @@ static int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsi
 int get_sha1(const char *name, unsigned char *sha1)
 {
 	int ret;
+	unsigned unused;
 
 	prepare_alt_odb();
 	ret = get_sha1_1(name, strlen(name), sha1);
@@ -518,7 +466,8 @@ int get_sha1(const char *name, unsigned char *sha1)
 		if (cp) {
 			unsigned char tree_sha1[20];
 			if (!get_sha1_1(name, cp-name, tree_sha1))
-				return get_tree_entry(tree_sha1, cp+1, sha1);
+				return get_tree_entry(tree_sha1, cp+1, sha1,
+						      &unused);
 		}
 	}
 	return ret;
diff --git a/templates/hooks--pre-commit b/templates/hooks--pre-commit
index 43d3b6ef4a..723a9ef210 100644
--- a/templates/hooks--pre-commit
+++ b/templates/hooks--pre-commit
@@ -61,6 +61,9 @@ perl -e '
 	    if (/^\s* 	/) {
 		bad_line("indent SP followed by a TAB", $_);
 	    }
+	    if (/^(?:[<>=]){7}/) {
+		bad_line("unresolved merge conflict", $_);
+	    }
 	}
     }
     exit($found_bad);
diff --git a/tree-walk.c b/tree-walk.c
index bf8bfdfdf8..9f7abb7cb3 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -115,3 +115,53 @@ void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callb
 	free(entry);
 }
 
+static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
+{
+	int namelen = strlen(name);
+	while (t->size) {
+		const char *entry;
+		const unsigned char *sha1;
+		int entrylen, cmp;
+
+		sha1 = tree_entry_extract(t, &entry, mode);
+		update_tree_entry(t);
+		entrylen = strlen(entry);
+		if (entrylen > namelen)
+			continue;
+		cmp = memcmp(name, entry, entrylen);
+		if (cmp > 0)
+			continue;
+		if (cmp < 0)
+			break;
+		if (entrylen == namelen) {
+			memcpy(result, sha1, 20);
+			return 0;
+		}
+		if (name[entrylen] != '/')
+			continue;
+		if (!S_ISDIR(*mode))
+			break;
+		if (++entrylen == namelen) {
+			memcpy(result, sha1, 20);
+			return 0;
+		}
+		return get_tree_entry(sha1, name + entrylen, result, mode);
+	}
+	return -1;
+}
+
+int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
+{
+	int retval;
+	void *tree;
+	struct tree_desc t;
+
+	tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
+	if (!tree)
+		return -1;
+	t.buf = tree;
+	retval = find_tree_entry(&t, name, sha1, mode);
+	free(tree);
+	return retval;
+}
+
diff --git a/tree-walk.h b/tree-walk.h
index 76893e36c3..47438fe1c0 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -22,4 +22,6 @@ typedef void (*traverse_callback_t)(int n, unsigned long mask, struct name_entry
 
 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback);
 
+int get_tree_entry(const unsigned char *, const char *, unsigned char *, unsigned *);
+
 #endif
diff --git a/unresolve.c b/unresolve.c
new file mode 100644
index 0000000000..0b23b9bc75
--- /dev/null
+++ b/unresolve.c
@@ -0,0 +1,146 @@
+#include "cache.h"
+#include "tree-walk.h"
+
+static const char unresolve_usage[] =
+"git-unresolve <paths>...";
+
+static struct cache_file cache_file;
+static unsigned char head_sha1[20];
+static unsigned char merge_head_sha1[20];
+
+static struct cache_entry *read_one_ent(const char *which,
+					unsigned char *ent, const char *path,
+					int namelen, int stage)
+{
+	unsigned mode;
+	unsigned char sha1[20];
+	int size;
+	struct cache_entry *ce;
+
+	if (get_tree_entry(ent, path, sha1, &mode)) {
+		error("%s: not in %s branch.", path, which);
+		return NULL;
+	}
+	if (mode == S_IFDIR) {
+		error("%s: not a blob in %s branch.", path, which);
+		return NULL;
+	}
+	size = cache_entry_size(namelen);
+	ce = xcalloc(1, size);
+
+	memcpy(ce->sha1, sha1, 20);
+	memcpy(ce->name, path, namelen);
+	ce->ce_flags = create_ce_flags(namelen, stage);
+	ce->ce_mode = create_ce_mode(mode);
+	return ce;
+}
+
+static int unresolve_one(const char *path)
+{
+	int namelen = strlen(path);
+	int pos;
+	int ret = 0;
+	struct cache_entry *ce_2 = NULL, *ce_3 = NULL;
+
+	/* See if there is such entry in the index. */
+	pos = cache_name_pos(path, namelen);
+	if (pos < 0) {
+		/* If there isn't, either it is unmerged, or
+		 * resolved as "removed" by mistake.  We do not
+		 * want to do anything in the former case.
+		 */
+		pos = -pos-1;
+		if (pos < active_nr) {
+			struct cache_entry *ce = active_cache[pos];
+			if (ce_namelen(ce) == namelen &&
+			    !memcmp(ce->name, path, namelen)) {
+				fprintf(stderr,
+					"%s: skipping still unmerged path.\n",
+					path);
+				goto free_return;
+			}
+		}
+	}
+
+	/* Grab blobs from given path from HEAD and MERGE_HEAD,
+	 * stuff HEAD version in stage #2,
+	 * stuff MERGE_HEAD version in stage #3.
+	 */
+	ce_2 = read_one_ent("our", head_sha1, path, namelen, 2);
+	ce_3 = read_one_ent("their", merge_head_sha1, path, namelen, 3);
+
+	if (!ce_2 || !ce_3) {
+		ret = -1;
+		goto free_return;
+	}
+	if (!memcmp(ce_2->sha1, ce_3->sha1, 20) &&
+	    ce_2->ce_mode == ce_3->ce_mode) {
+		fprintf(stderr, "%s: identical in both, skipping.\n",
+			path);
+		goto free_return;
+	}
+
+	remove_file_from_cache(path);
+	if (add_cache_entry(ce_2, ADD_CACHE_OK_TO_ADD)) {
+		error("%s: cannot add our version to the index.", path);
+		ret = -1;
+		goto free_return;
+	}
+	if (!add_cache_entry(ce_3, ADD_CACHE_OK_TO_ADD))
+		return 0;
+	error("%s: cannot add their version to the index.", path);
+	ret = -1;
+ free_return:
+	free(ce_2);
+	free(ce_3);
+	return ret;
+}
+
+static void read_head_pointers(void)
+{
+	if (read_ref(git_path("HEAD"), head_sha1))
+		die("Cannot read HEAD -- no initial commit yet?");
+	if (read_ref(git_path("MERGE_HEAD"), merge_head_sha1)) {
+		fprintf(stderr, "Not in the middle of a merge.\n");
+		exit(0);
+	}
+}
+
+int main(int ac, char **av)
+{
+	int i;
+	int err = 0;
+	int newfd;
+
+	if (ac < 2)
+		usage(unresolve_usage);
+
+	git_config(git_default_config);
+
+	/* Read HEAD and MERGE_HEAD; if MERGE_HEAD does not exist, we
+	 * are not doing a merge, so exit with success status.
+	 */
+	read_head_pointers();
+
+	/* Otherwise we would need to update the cache. */
+	newfd= hold_index_file_for_update(&cache_file, get_index_file());
+	if (newfd < 0)
+		die("unable to create new cachefile");
+
+	if (read_cache() < 0)
+		die("cache corrupted");
+
+	for (i = 1; i < ac; i++) {
+		char *arg = av[i];
+		err |= unresolve_one(arg);
+	}
+	if (err)
+		die("Error encountered; index not updated.");
+
+	if (active_cache_changed) {
+		if (write_cache(newfd, active_cache, active_nr) ||
+		    commit_index_file(&cache_file))
+			die("Unable to write new cachefile");
+	}
+	return 0;
+}