Re: [PATCH 04/10] evolve: add support for parsing metacommits
- From
- Phillip Wood <phillip.wood123@gmail.com>
- Date
- Sep 26, 2022, 13:27 UTC
- Message-ID
- <e7278794-428d-4aff-e91b-d2e6527f142d@gmail.com>
- In-Reply-To
- <2e9a4a9bd819785404e8a5343385f4fb2bc06109.1663959325.git.gitgitgadget@gmail.com>
Hi Chris
On 23/09/2022 19:55, Stefan Xenos via GitGitGadget wrote:
Show 26 quoted lines
> From: Stefan Xenos <sxenos@google.com> > > This patch adds the get_metacommit_content method, which can classify > commits as either metacommits or normal commits, determine whether they > are abandoned, and extract the content commit's object id from the > metacommit. > > Signed-off-by: Stefan Xenos <sxenos@google.com> > Signed-off-by: Chris Poucet <poucet@google.com> > --- > Makefile | 1 + > metacommit-parser.c | 110 ++++++++++++++++++++++++++++++++++++++++++++ > metacommit-parser.h | 19 ++++++++ > 3 files changed, 130 insertions(+) > create mode 100644 metacommit-parser.c > create mode 100644 metacommit-parser.h > > diff --git a/Makefile b/Makefile > index cac3452edb9..b2bcc00c289 100644 > --- a/Makefile > +++ b/Makefile > @@ -999,6 +999,7 @@ LIB_OBJS += merge-ort.o > LIB_OBJS += merge-ort-wrappers.o > LIB_OBJS += merge-recursive.o > LIB_OBJS += merge.o > +LIB_OBJS += metacommit-parser.o
There seems to be a problem with the indent here
> LIB_OBJS += midx.o > LIB_OBJS += name-hash.o > LIB_OBJS += negotiator/default.o
> diff --git a/metacommit-parser.h b/metacommit-parser.h > new file mode 100644 > index 00000000000..1c74bd6d699 > --- /dev/null > +++ b/metacommit-parser.h > @@ -0,0 +1,19 @@ > +#ifndef METACOMMIT_PARSER_H > +#define METACOMMIT_PARSER_H > + > +#include "commit.h" > +#include "hash.h" > + > +/* Indicates a normal commit (non-metacommit) */ > +#define METACOMMIT_TYPE_NONE 0 > +/* Indicates a metacommit with normal content (non-abandoned) */ > +#define METACOMMIT_TYPE_NORMAL 1 > +/* Indicates a metacommit with abandoned content */ > +#define METACOMMIT_TYPE_ABANDONED 2
Is it possible to define these as an enum? It would make the signature of get_meta_commit_content() nicer.
> +struct commit;
What's this for? We're including commit.h above.
> +extern int get_metacommit_content( > + struct commit *commit, struct object_id *content);
Show 14 quoted lines
> diff --git a/metacommit-parser.c b/metacommit-parser.c > new file mode 100644 > index 00000000000..70c1428bfc6 > --- /dev/null > +++ b/metacommit-parser.c > @@ -0,0 +1,110 @@ > +#include "cache.h" > +#include "metacommit-parser.h" > +#include "commit.h" > + > +/* > + * Search the commit buffer for a line starting with the given key. Unlike > + * find_commit_header, this also searches the commit message body. > + */
There is no explanation in the code or commit message as to why this function is needed. The documentation added in the first commit says that "parent-type" header is a commit header. I think the answer is that this series does not implement that header but uses the commit message instead. That's perfectly fine for a proof of concept but it is precisely the sort of detail that should be described it the commit message and probably flagged up in the cover letter.
Show 30 quoted lines
> +static const char *find_key(const char *msg, const char *key, size_t *out_len)
> +{
> + int key_len = strlen(key);
> + const char *line = msg;
> +
> + while (line) {
> + const char *eol = strchrnul(line, '\n');
> +
> + if (eol - line > key_len && !memcmp(line, key, key_len) &&
> + line[key_len] == ' ') {
> + *out_len = eol - line - key_len - 1;
> + return line + key_len + 1;
> + }
> + line = *eol ? eol + 1 : NULL;
> + }
> + return NULL;
> +}
> +
> +static struct commit *get_commit_by_index(struct commit_list *to_search, int index)
> +{
> + while (to_search && index) {
> + to_search = to_search->next;
> + index--;
> + }
> +
> + if (!to_search)
> + return NULL;
> +
> + return to_search->item;
> +}This function is a useful utility for struct commit_list and should live in commit.c. It could be used to simplify object-name.c:get_parent() for example.
Show 5 quoted lines
> +/* > + * Writes the index of the content parent to "result". Returns the metacommit > + * type. See the METACOMMIT_TYPE_* constants. > + */ > +static int index_of_content_commit(const char *buffer, int *result)
I found the signature confusing as it is returning an int but that is not the index. Switching to an enum for the metacommit types would clarify that.
Show 19 quoted lines
> +{
> + int index = 0;
> + int ret = METACOMMIT_TYPE_NONE;
> + size_t parent_types_size;
> + const char *parent_types = find_key(buffer, "parent-type",
> + &parent_types_size);
> + const char *end;
> + const char *enum_start = parent_types;
> + int enum_length = 0;
> +
> + if (!parent_types)
> + return METACOMMIT_TYPE_NONE;
> +
> + end = &parent_types[parent_types_size];
> +
> + while (1) {
> + char next = *parent_types;
> + if (next == ' ' || parent_types >= end) {
> + if (enum_length == 1) {if enum_length != 1 then there is an error in the parent-type header and we should probably bail out.
> + char first_char_in_enum = *enum_start;
It's not just the first character, it's the only character, do we really need such a long variable name? (how about just calling it "type")
I'll try and take at look at the next couple of patches later in the week.
Best Wishes
Phillip