Merge branch 'rs/pretty-add-again' into maint

The pretty-format specifiers like '%h', '%t', etc. had an
optimization that no longer works correctly.  In preparation/hope
of getting it correctly implemented, first discard the optimization
that is broken.

* rs/pretty-add-again:
  pretty: recalculate duplicate short hashes

pretty.c

@@ -783,29 +783,9 @@ struct format_commit_context {
 	size_t body_off;
 
 	/* The following ones are relative to the result struct strbuf. */
-	struct chunk abbrev_commit_hash;
-	struct chunk abbrev_tree_hash;
-	struct chunk abbrev_parent_hashes;
 	size_t wrap_start;
 };
 
-static int add_again(struct strbuf *sb, struct chunk *chunk)
-{
-	if (chunk->len) {
-		strbuf_adddup(sb, chunk->off, chunk->len);
-		return 1;
-	}
-
-	/*
-	 * We haven't seen this chunk before.  Our caller is surely
-	 * going to add it the hard way now.  Remember the most likely
-	 * start of the to-be-added chunk: the current end of the
-	 * struct strbuf.
-	 */
-	chunk->off = sb->len;
-	return 0;
-}
-
 static void parse_commit_header(struct format_commit_context *context)
 {
 	const char *msg = context->message;
@@ -1147,24 +1127,16 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 		return 1;
 	case 'h':		/* abbreviated commit hash */
 		strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_COMMIT));
-		if (add_again(sb, &c->abbrev_commit_hash)) {
-			strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_RESET));
-			return 1;
-		}
 		strbuf_add_unique_abbrev(sb, commit->object.oid.hash,
 					 c->pretty_ctx->abbrev);
 		strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_RESET));
-		c->abbrev_commit_hash.len = sb->len - c->abbrev_commit_hash.off;
 		return 1;
 	case 'T':		/* tree hash */
 		strbuf_addstr(sb, oid_to_hex(&commit->tree->object.oid));
 		return 1;
 	case 't':		/* abbreviated tree hash */
-		if (add_again(sb, &c->abbrev_tree_hash))
-			return 1;
 		strbuf_add_unique_abbrev(sb, commit->tree->object.oid.hash,
 					 c->pretty_ctx->abbrev);
-		c->abbrev_tree_hash.len = sb->len - c->abbrev_tree_hash.off;
 		return 1;
 	case 'P':		/* parent hashes */
 		for (p = commit->parents; p; p = p->next) {
@@ -1174,16 +1146,12 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 		}
 		return 1;
 	case 'p':		/* abbreviated parent hashes */
-		if (add_again(sb, &c->abbrev_parent_hashes))
-			return 1;
 		for (p = commit->parents; p; p = p->next) {
 			if (p != commit->parents)
 				strbuf_addch(sb, ' ');
 			strbuf_add_unique_abbrev(sb, p->item->object.oid.hash,
 						 c->pretty_ctx->abbrev);
 		}
-		c->abbrev_parent_hashes.len = sb->len -
-		                              c->abbrev_parent_hashes.off;
 		return 1;
 	case 'm':		/* left/right/bottom */
 		strbuf_addstr(sb, get_revision_mark(NULL, commit));

strbuf.c

@@ -204,13 +204,6 @@ void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
 	strbuf_setlen(sb, sb->len + sb2->len);
 }
 
-void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
-{
-	strbuf_grow(sb, len);
-	memcpy(sb->buf + sb->len, sb->buf + pos, len);
-	strbuf_setlen(sb, sb->len + len);
-}
-
 void strbuf_addchars(struct strbuf *sb, int c, size_t n)
 {
 	strbuf_grow(sb, n);

strbuf.h

@@ -263,12 +263,6 @@ static inline void strbuf_addstr(struct strbuf *sb, const char *s)
  */
 extern void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2);
 
-/**
- * Copy part of the buffer from a given position till a given length to the
- * end of the buffer.
- */
-extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
-
 /**
  * This function can be used to expand a format string containing
  * placeholders. To that end, it parses the string and calls the specified