Merge branch 'jk/external-diff-use-argv-array' (early part)

Crash fix for codepath that miscounted the necessary size for an
array when spawning an external diff program.

* 'jk/external-diff-use-argv-array' (early part):
run_external_diff: use an argv_array for the command line

diff --combined diff.c
index 54d530826881684c916a78a4334579a2e401ee47,76ae3790324c6ef6007a939af9b82327130d1bd2..f72769a1c492dfcac501032c54c3fb2ac0a4343e
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -16,6 -16,7 +16,7 @@@
  #include "submodule.h"
  #include "ll-merge.h"
  #include "string-list.h"
+ #include "argv-array.h"
  
  #ifdef NO_FAST_WORKING_DIRECTORY
  #define FAST_WORKING_DIRECTORY 0
@@@ -1361,7 -1362,11 +1362,7 @@@ static struct diffstat_file *diffstat_a
  {
        struct diffstat_file *x;
        x = xcalloc(sizeof (*x), 1);
 -      if (diffstat->nr == diffstat->alloc) {
 -              diffstat->alloc = alloc_nr(diffstat->alloc);
 -              diffstat->files = xrealloc(diffstat->files,
 -                              diffstat->alloc * sizeof(x));
 -      }
 +      ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
        diffstat->files[diffstat->nr++] = x;
        if (name_b) {
                x->from_name = xstrdup(name_a);
@@@ -1461,12 -1466,20 +1462,12 @@@ int print_stat_summary(FILE *fp, int fi
         * but nothing about added/removed lines? Is this a bug in Git?").
         */
        if (insertions || deletions == 0) {
 -              /*
 -               * TRANSLATORS: "+" in (+) is a line addition marker;
 -               * do not translate it.
 -               */
                strbuf_addf(&sb,
                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
                            insertions);
        }
  
        if (deletions || insertions == 0) {
 -              /*
 -               * TRANSLATORS: "-" in (-) is a line removal marker;
 -               * do not translate it.
 -               */
                strbuf_addf(&sb,
                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
                            deletions);
@@@ -2894,9 -2907,8 +2895,8 @@@ static void run_external_diff(const cha
                              int complete_rewrite,
                              struct diff_options *o)
  {
-       const char *spawn_arg[10];
+       struct argv_array argv = ARGV_ARRAY_INIT;
        int retval;
-       const char **arg = &spawn_arg[0];
        struct diff_queue_struct *q = &diff_queued_diff;
        const char *env[3] = { NULL };
        char env_counter[50];
@@@ -2907,23 -2919,22 +2907,22 @@@
                const char *othername = (other ? other : name);
                temp_one = prepare_temp_file(name, one);
                temp_two = prepare_temp_file(othername, two);
-               *arg++ = pgm;
-               *arg++ = name;
-               *arg++ = temp_one->name;
-               *arg++ = temp_one->hex;
-               *arg++ = temp_one->mode;
-               *arg++ = temp_two->name;
-               *arg++ = temp_two->hex;
-               *arg++ = temp_two->mode;
+               argv_array_push(&argv, pgm);
+               argv_array_push(&argv, name);
+               argv_array_push(&argv, temp_one->name);
+               argv_array_push(&argv, temp_one->hex);
+               argv_array_push(&argv, temp_one->mode);
+               argv_array_push(&argv, temp_two->name);
+               argv_array_push(&argv, temp_two->hex);
+               argv_array_push(&argv, temp_two->mode);
                if (other) {
-                       *arg++ = other;
-                       *arg++ = xfrm_msg;
+                       argv_array_push(&argv, other);
+                       argv_array_push(&argv, xfrm_msg);
                }
        } else {
-               *arg++ = pgm;
-               *arg++ = name;
+               argv_array_push(&argv, pgm);
+               argv_array_push(&argv, name);
        }
-       *arg = NULL;
        fflush(NULL);
  
        env[0] = env_counter;
@@@ -2932,8 -2943,9 +2931,9 @@@
        env[1] = env_total;
        snprintf(env_total, sizeof(env_total), "GIT_DIFF_PATH_TOTAL=%d", q->nr);
  
-       retval = run_command_v_opt_cd_env(spawn_arg, RUN_USING_SHELL, NULL, env);
+       retval = run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env);
        remove_tempfile();
+       argv_array_clear(&argv);
        if (retval) {
                fprintf(stderr, "external diff died, stopping at %s.\n", name);
                exit(1);
@@@ -3354,11 -3366,14 +3354,11 @@@ static int opt_arg(const char *arg, in
        if (c != '-')
                return 0;
        arg++;
 -      eq = strchr(arg, '=');
 -      if (eq)
 -              len = eq - arg;
 -      else
 -              len = strlen(arg);
 +      eq = strchrnul(arg, '=');
 +      len = eq - arg;
        if (!len || strncmp(arg, arg_long, len))
                return 0;
 -      if (eq) {
 +      if (*eq) {
                int n;
                char *end;
                if (!isdigit(*++eq))
@@@ -3585,6 -3600,14 +3585,6 @@@ static int parse_diff_filter_opt(const 
        return 0;
  }
  
 -/* Used only by "diff-files" and "diff --no-index" */
 -void handle_deprecated_show_diff_q(struct diff_options *opt)
 -{
 -      warning("'diff -q' and 'diff-files -q' are deprecated.");
 -      warning("Use 'diff --diff-filter=d' instead to ignore deleted filepairs.");
 -      parse_diff_filter_opt("d", opt);
 -}
 -
  static void enable_patch_output(int *fmt) {
        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
        *fmt |= DIFF_FORMAT_PATCH;
@@@ -3943,7 -3966,11 +3943,7 @@@ struct diff_queue_struct diff_queued_di
  
  void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
  {
 -      if (queue->alloc <= queue->nr) {
 -              queue->alloc = alloc_nr(queue->alloc);
 -              queue->queue = xrealloc(queue->queue,
 -                                      sizeof(dp) * queue->alloc);
 -      }
 +      ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
        queue->queue[queue->nr++] = dp;
  }