diff -c/--cc: do not mistake "resolved as deletion" as "use working tree"

The combined diff machinery can be used to compare:

 - a merge commit with its parent commits;
 - a working-tree file with multiple stages in an unmerged index; or
 - a working-tree file with the HEAD and the index.

The internal function combine-diff.c:show_patch_diff() checked if it needs
to read the "result" from the working tree by looking at the object name
of the result --- if it is null_sha1, it read from the working tree.

This mistook a merge that records a deletion as the conflict resolution
as if it is a cue to read from the working tree. Pass this information
explicitly from the caller instead.

Noticed and reported by Johan Herland.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/combine-diff.c b/combine-diff.c
index 655fa89d8a7ffe3c3823080f5af3e5e385e95440..360b816b3ef7e08cbeef9c9823e212354f8847eb 100644 (file)
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -682,7 +682,8 @@ static void dump_quoted_path(const char *head,
 }
 
 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
-                           int dense, struct rev_info *rev)
+                           int dense, int working_tree_file,
+                           struct rev_info *rev)
 {
        struct diff_options *opt = &rev->diffopt;
        unsigned long result_size, cnt, lno;
@@ -691,7 +692,6 @@ static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
        struct sline *sline; /* survived lines */
        int mode_differs = 0;
        int i, show_hunks;
-       int working_tree_file = is_null_sha1(elem->sha1);
        int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
        const char *a_prefix, *b_prefix;
        mmfile_t result_file;
@@ -954,6 +954,12 @@ static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct re
        write_name_quoted(p->path, stdout, line_termination);
 }
 
+/*
+ * The result (p->elem) is from the working tree and their
+ * parents are typically from multiple stages during a merge
+ * (i.e. diff-files) or the state in HEAD and in the index
+ * (i.e. diff-index).
+ */
 void show_combined_diff(struct combine_diff_path *p,
                       int num_parent,
                       int dense,
@@ -967,7 +973,7 @@ void show_combined_diff(struct combine_diff_path *p,
                                  DIFF_FORMAT_NAME_STATUS))
                show_raw_diff(p, num_parent, rev);
        else if (opt->output_format & DIFF_FORMAT_PATCH)
-               show_patch_diff(p, num_parent, dense, rev);
+               show_patch_diff(p, num_parent, dense, 1, rev);
 }
 
 void diff_tree_combined(const unsigned char *sha1,
@@ -1035,7 +1041,7 @@ void diff_tree_combined(const unsigned char *sha1,
                        for (p = paths; p; p = p->next) {
                                if (p->len)
                                        show_patch_diff(p, num_parent, dense,
-                                                       rev);
+                                                       0, rev);
                        }
                }
        }