Re: [PATCH v2] refs: add GIT_TRACE_REFS debugging mechanism

From: Han-Wen Nienhuys <hanwen@google.com>
Date: Sep 9, 2020, 09:43 UTC
Message-ID: <CAFQ2z_OOCvFH-+FNdPWjQ=vGwgeBdVzMjt8avm6AkX=H81kPdQ@mail.gmail.com>
In-Reply-To: <xmqq7dt4x957.fsf@gitster.c.googlers.com>

On Tue, Sep 8, 2020 at 11:15 PM Junio C Hamano <gitster@pobox.com> wrote:

> Cute.  I like it.

thanks :)

> > +     res = malloc(sizeof(struct debug_ref_store));
> > +     be_copy = malloc(sizeof(*be_copy));
>
> Not xmalloc() and friends?

done.

Show 7 quoted lines

>
> > +     *be_copy = refs_be_debug;
> > +     be_copy->name = store->be->name;
>
> I guess we never destroy the ref-store instances so it is OK to
> assume that it would not cause problems later by sharing pieces of
> memory with underlying "real" thing like this.

correct. But changed to xstrdup to avoid confusion.

> > +     char o[200] = "null";
> > +     char n[200] = "null";
>
> I thought we had better constant than 200 (later you use 100 in the

done.

> same patch).  I am not sure how I feel about "null"; all places in
> Git, we tend to use 0{length-of-the-hash} for "no object name on
> this side", I think.

Some functions take NULL as a legitimate parameter, eg. a transaction update with NULL as old OID (don't check old OID) is different from an update with 0{40} as old OID. (ref must not exist yet).

Show 5 quoted lines

> > +     for (int i = 0; i < transaction->nr; i++) {
>
> We still do not allow variable decl inside the set-up part of a
> for(;;) statement, if I recall Documentation/CodingGuidelines
> correctly.

Fixed.

Show 9 quoted lines

> > +static int debug_delete_refs(struct ref_store *ref_store, const char *msg,
> > +                          struct string_list *refnames, unsigned int flags)
> > +{
> > +     struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
> > +     int res =
> > +             drefs->refs->be->delete_refs(drefs->refs, msg, refnames, flags);
> > +     int i = 0;
>
> No need to initialize 'i' here.

Fixed.

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Han-Wen Nienhuys - Google Munich
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