Re: [RFC/PATCH] notes-util.c: replace git_config with git_config_get_string

On Mon, Jun 30, 2014 at 9:34 AM, Karsten Blees [off-list ref] wrote:

Am 29.06.2014 13:01, schrieb Eric Sunshine:

quoted

On Thu, Jun 26, 2014 at 4:19 AM, Tanay Abhra [off-list ref] wrote:

quoted

On 6/25/2014 1:24 PM, Eric Sunshine wrote:

quoted

On Mon, Jun 23, 2014 at 6:41 AM, Tanay Abhra [off-list ref] wrote:

quoted

Use git_config_get_string instead of git_config to take advantage of
the config hash-table api which provides a cleaner control flow.

Signed-off-by: Tanay Abhra <redacted>
---
 notes-utils.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/notes-utils.c b/notes-utils.c
index a0b1d7b..fdc9912 100644
--- a/notes-utils.c
+++ b/notes-utils.c

@@ -68,22 +68,23 @@ static combine_notes_fn parse_combine_notes_fn(const char *v)
                return NULL;
 }

-static int notes_rewrite_config(const char *k, const char *v, void *cb)
+static void notes_rewrite_config(struct notes_rewrite_cfg *c)
 {
-       struct notes_rewrite_cfg *c = cb;
-       if (starts_with(k, "notes.rewrite.") && !strcmp(k+14, c->cmd)) {
-               c->enabled = git_config_bool(k, v);
-               return 0;
-       } else if (!c->mode_from_env && !strcmp(k, "notes.rewritemode")) {
+       struct strbuf key = STRBUF_INIT;
+       const char *v;
+       strbuf_addf(&key, "notes.rewrite.%s", c->cmd);
+
+       if (!git_config_get_string(key.buf, &v))
+               c->enabled = git_config_bool(key.buf, v);
+
+       if (!c->mode_from_env && !git_config_get_string("notes.rewritemode", &v)) {
                if (!v)
-                       return config_error_nonbool(k);
+                       config_error_nonbool("notes.rewritemode");

There's a behavior change here. In the original code, the callback
function would return -1, which would cause the program to die() if
the config.c:die_on_error flag was set. The new code merely emits an
error.

Is this change serious enough? Can I ignore it?

IMO its better to Fail Fast than continue with some invalid config (which
may lead to more severe errors such as data corruption / data loss).

quoted

I don't know. Even within this single function there is no consistency
about whether such problems should die() or just emit a message and
continue. For instance:

- if "notes.rewritemode" is bool, it die()s.

- if "notes.rewritemode" doesn't specify a recognized mode, it
error()s but continues

I think this would also die in git_parse_source():
...
    if (get_value(fn, data, var) < 0)
      break;
  }
  if (cf->die_on_error)
    die("bad config file line %d in %s", cf->linenr, cf->name);
...

One would expect so, but notes-utils.c:notes_rewrite_config() is
actually doing this:

    if (!c->combine) {
        error(_("Bad notes.rewriteMode value: '%s'"), v);
        return 1;
    }

Rather than returning the -1 result of error(), which would make
git_parse_source() die(), it's explicitly returning 1, which
get_parse_source() ignores.

(AFAICT, die_on_error is always true, except if invoked via 'git-config
--blob', which isn't used anywhere...)

This, however, raises another issue: switching to the config cache looses
file/line-precise error reporting for semantic errors. I don't know if
this feature is important enough to do something about it, though. A
message of the form "Key 'xyz' is bad" should usually enable a user to
locate the problematic file and line.