From: Junio C Hamano <gitster@pobox.com>
To: Patrick Steinhardt <ps@pks.im>
Cc: git@vger.kernel.org, Christian Couder <christian.couder@gmail.com>
Subject: Re: [PATCH v2 1/4] fetch: extract writing to FETCH_HEAD
Date: Fri, 08 Jan 2021 15:40:17 -0800 [thread overview]
Message-ID: <xmqqmtxjgfq6.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <d80dbc5a9c9520621651541e418ee5216d164053.1610107599.git.ps@pks.im> (Patrick Steinhardt's message of "Fri, 8 Jan 2021 13:11:14 +0100")
Patrick Steinhardt <ps@pks.im> writes:
> +static int open_fetch_head(struct fetch_head *fetch_head)
> +{
> + const char *filename = git_path_fetch_head(the_repository);
> +
> + if (!write_fetch_head)
> + return 0;
> +
> + fetch_head->fp = fopen(filename, "a");
> + if (!fetch_head->fp)
> + return error_errno(_("cannot open %s"), filename);
> +
> + return 0;
> +}
So the difference from the original, which used to have a writable
filehandle to /dev/null in the dry-run mode, is that fetch_head->fp
is left as-is (not even NULLed out).
> +static void append_fetch_head(struct fetch_head *fetch_head, const char *old_oid,
It is clear from the type these days but variable names like
"old_oid" hint the readers that they are not a hexadecimal object
name string but either an array of uchar[40] or a struct object_id;
perhaps "old_oid_hex" would be less misleading.
If the caller does have struct object_id, then it would be even
better to take it as-is as a parameter and use oid_to_hex_r() on it in
this function when it is given to fprintf(). [Nit #1]
> + const char *merge_status_marker, const char *note,
> + const char *url, size_t url_len)
> +{
> + size_t i;
> +
> + if (!write_fetch_head)
> + return;
Presumably, this check is what makes sure that fetch_head->fp that
is left uninitialized will never gets used.
> + fprintf(fetch_head->fp, "%s\t%s\t%s",
> + old_oid, merge_status_marker, note);
> + for (i = 0; i < url_len; ++i)
> + if ('\n' == url[i])
> + fputs("\\n", fetch_head->fp);
> + else
> + fputc(url[i], fetch_head->fp);
> + fputc('\n', fetch_head->fp);
> +}
OK. This is the "case FETCH_HEAD_NOT_FOR_MERGE" and "case
FETCH_HEAD_MERGE" parts in the original.
As an abstraction, it may be better to make the caller pass a
boolean "is this for merge?" and keep the knowledge of what exact
string is used for merge_status_marker to this function, instead of
letting the caller passing it as a parameter in the string form.
After all, we never allow anything other than an empty string or a
fixed "not-for-merge" string in that place in the file format.
[Nit #2]
> +static void commit_fetch_head(struct fetch_head *fetch_head)
> +{
> + /* Nothing to commit yet. */
> +}
> +
> +static void close_fetch_head(struct fetch_head *fetch_head)
> +{
> + if (!write_fetch_head)
> + return;
So is this check a protection against uninitialized fetch_head->fp.
Both changes make sense.
> + fclose(fetch_head->fp);
> +}
> @@ -909,22 +959,19 @@ N_("It took %.2f seconds to check forced updates. You can use\n"
> static int store_updated_refs(const char *raw_url, const char *remote_name,
> int connectivity_checked, struct ref *ref_map)
> {
> - FILE *fp;
> + struct fetch_head fetch_head;
And that is why this variable is left uninitialised on stack and it
is OK. An alternative design would be to initialize fetch_head.fp
to NULL, and return early with "if (!fetch_head->fp)" in the two
functions that take fetch_head struct. That way, we have less
reliance on the global variable write_fetch_head.
> struct commit *commit;
> int url_len, i, rc = 0;
> struct strbuf note = STRBUF_INIT;
> const char *what, *kind;
> struct ref *rm;
> char *url;
> - const char *filename = (!write_fetch_head
> - ? "/dev/null"
> - : git_path_fetch_head(the_repository));
> int want_status;
> int summary_width = transport_summary_width(ref_map);
>
> - fp = fopen(filename, "a");
> - if (!fp)
> - return error_errno(_("cannot open %s"), filename);
> + rc = open_fetch_head(&fetch_head);
> + if (rc)
> + return -1;
OK, we've already said "cannot open" in the open_fetch_head()
function, so we just return an error silently.
> @@ -1016,16 +1063,10 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
> merge_status_marker = "not-for-merge";
> /* fall-through */
> case FETCH_HEAD_MERGE:
> - fprintf(fp, "%s\t%s\t%s",
> - oid_to_hex(&rm->old_oid),
> - merge_status_marker,
> - note.buf);
> - for (i = 0; i < url_len; ++i)
> - if ('\n' == url[i])
> - fputs("\\n", fp);
> - else
> - fputc(url[i], fp);
> - fputc('\n', fp);
> + append_fetch_head(&fetch_head,
> + oid_to_hex(&rm->old_oid),
> + merge_status_marker,
> + note.buf, url, url_len);
Here, we can lose merge_status_marker variable from this caller, and
then this caller becomes:
switch (rm->fetch_head_status) {
case FETCH_HEAD_NOT_FOR_MERGE:
case FETCH_HEAD_MERGE:
append_fetch_head(&fetch_head, &rm->old_oid,
rm->fetch_head_status == FETCH_HEAD_MERGE,
note.buf, url, url_len);
Note that I am passing "is this a ref to be merged?" boolean to keep
the exact string of "not-for-merge" in the callee.
> @@ -1060,6 +1101,9 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
> }
> }
>
> + if (!rc)
> + commit_fetch_head(&fetch_head);
> +
> if (rc & STORE_REF_ERROR_DF_CONFLICT)
> error(_("some local refs could not be updated; try running\n"
> " 'git remote prune %s' to remove any old, conflicting "
> @@ -1077,7 +1121,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
> abort:
> strbuf_release(¬e);
> free(url);
> - fclose(fp);
> + close_fetch_head(&fetch_head);
> return rc;
> }
Other than the above two nits, this step looks good to me.
Thanks.
next prev parent reply other threads:[~2021-01-08 23:41 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 13:51 [PATCH 0/2] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-07 13:51 ` [PATCH 1/2] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-07 22:59 ` Junio C Hamano
2021-01-08 0:45 ` Christian Couder
2021-01-08 7:18 ` Junio C Hamano
2021-01-07 13:51 ` [PATCH 2/2] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-08 0:19 ` Junio C Hamano
2021-01-08 12:11 ` [PATCH v2 0/4] " Patrick Steinhardt
2021-01-08 12:11 ` [PATCH v2 1/4] fetch: extract writing to FETCH_HEAD Patrick Steinhardt
2021-01-08 23:40 ` Junio C Hamano [this message]
2021-01-11 10:26 ` Patrick Steinhardt
2021-01-11 19:24 ` Junio C Hamano
2021-01-08 12:11 ` [PATCH v2 2/4] fetch: refactor `s_update_ref` to use common exit path Patrick Steinhardt
2021-01-08 23:50 ` Junio C Hamano
2021-01-11 10:28 ` Patrick Steinhardt
2021-01-08 12:11 ` [PATCH v2 3/4] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-08 23:53 ` Junio C Hamano
2021-01-08 12:11 ` [PATCH v2 4/4] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-09 0:05 ` Junio C Hamano
2021-01-11 10:42 ` Patrick Steinhardt
2021-01-11 19:47 ` Junio C Hamano
2021-01-12 12:22 ` Patrick Steinhardt
2021-01-12 12:29 ` Patrick Steinhardt
2021-01-12 19:19 ` Junio C Hamano
2021-01-11 11:05 ` [PATCH v3 0/5] " Patrick Steinhardt
2021-01-11 11:05 ` [PATCH v3 1/5] fetch: extract writing to FETCH_HEAD Patrick Steinhardt
2021-01-11 23:16 ` Junio C Hamano
2021-01-11 11:05 ` [PATCH v3 2/5] fetch: use strbuf to format FETCH_HEAD updates Patrick Steinhardt
2021-01-11 11:10 ` Patrick Steinhardt
2021-01-11 11:17 ` Christian Couder
2021-01-11 23:21 ` Junio C Hamano
2021-01-11 11:05 ` [PATCH v3 3/5] fetch: refactor `s_update_ref` to use common exit path Patrick Steinhardt
2021-01-11 11:05 ` [PATCH v3 4/5] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-11 11:05 ` [PATCH v3 5/5] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-12 0:04 ` [PATCH v3 0/5] " Junio C Hamano
2021-01-12 12:27 ` [PATCH v4 " Patrick Steinhardt
2021-01-12 12:27 ` [PATCH v4 1/5] fetch: extract writing to FETCH_HEAD Patrick Steinhardt
2021-01-12 12:27 ` [PATCH v4 2/5] fetch: use strbuf to format FETCH_HEAD updates Patrick Steinhardt
2021-01-12 12:27 ` [PATCH v4 3/5] fetch: refactor `s_update_ref` to use common exit path Patrick Steinhardt
2021-01-12 12:27 ` [PATCH v4 4/5] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-12 12:27 ` [PATCH v4 5/5] fetch: implement support for atomic reference updates Patrick Steinhardt
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