checkout: Don't crash when switching away from an invalid branch.

diff --git a/builtin-diff.c b/builtin-diff.c
index 4c289e798a25ee3893a483abd8465740999dcbef..d5fe775fc135c0905cabec6731104009ca3bfef3 100644 (file)
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -21,7 +21,7 @@ struct blobinfo {
 };
 
 static const char builtin_diff_usage[] =
-"git-diff <options> <rev>{0,2} -- <path>*";
+"git diff <options> <rev>{0,2} -- <path>*";
 
 static void stuff_change(struct diff_options *opt,
                         unsigned old_mode, unsigned new_mode,
@@ -122,6 +122,8 @@ static int builtin_diff_index(struct rev_info *revs,
                        usage(builtin_diff_usage);
                argv++; argc--;
        }
+       if (!cached)
+               setup_work_tree();
        /*
         * Make sure there is one revision (i.e. pending object),
         * and there is no revision filtering parameters.
@@ -221,10 +223,17 @@ static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv
                argv++; argc--;
        }
 
-       if (revs->max_count == -1 &&
+       /*
+        * "diff --base" should not combine merges because it was not
+        * asked to.  "diff -c" should not densify (if the user wants
+        * dense one, --cc can be explicitly asked for, or just rely
+        * on the default).
+        */
+       if (revs->max_count == -1 && !revs->combine_merges &&
            (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
                revs->combine_merges = revs->dense_combined_merges = 1;
 
+       setup_work_tree();
        if (read_cache() < 0) {
                perror("read_cache");
                return -1;
@@ -296,7 +305,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
         * If the user asked for our exit code then don't start a
         * pager or we would end up reporting its exit code instead.
         */
-       if (!DIFF_OPT_TST(&rev.diffopt, EXIT_WITH_STATUS))
+       if (!DIFF_OPT_TST(&rev.diffopt, EXIT_WITH_STATUS) &&
+           check_pager_config("diff") != 0)
                setup_pager();
 
        /*