From: Phillip Wood Date: Mon, 26 Sep 2022 13:27:31 GMT Subject: Re: [PATCH 04/10] evolve: add support for parsing metacommits Message-ID: In-Reply-To: <2e9a4a9bd819785404e8a5343385f4fb2bc06109.1663959325.git.gitgitgadget@gmail.com> Hi Chris On 23/09/2022 19:55, Stefan Xenos via GitGitGadget wrote: > From: Stefan Xenos > > 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 > Signed-off-by: Chris Poucet > --- > 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); > 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. > +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. > +/* > + * 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. > +{ > + 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