Karthik Nayak <karthik.188@xxxxxxxxx> writes:
> The contents of the .gitattributes files may evolve over time, but "git
> check-attr" always checks attributes against them in the working tree
> and/or in the index. It may be beneficial to optionally allow the users
> to check attributes taken from a commit other than HEAD against paths.
>
> Add a new flag `--source` which will allow users to check the
> attributes against a commit (actually any tree-ish would do). When the
> user uses this flag, we go through the stack of .gitattributes files but
> instead of checking the current working tree and/or in the index, we
> check the blobs from the provided tree-ish object. This allows the
> command to also be used in bare repositories.
>
> Since we use a tree-ish object, the user can pass "--source
> HEAD:subdirectory" and all the attributes will be looked up as if
> subdirectory was the root directory of the repository.
>
> We cannot simply use the `<rev>:<path>` syntax without the `--source`
> flag, similar to how it is used in `git show` because any non-flag
> parameter before `--` is treated as an attribute and any parameter after
> `--` is treated as a pathname.
>
> The change involves creating a new function `read_attr_from_blob`, which
> given the path reads the blob for the path against the provided source and
> parses the attributes line by line. This function is plugged into
> `read_attr()` function wherein we go through the stack of attributes
> files.
>
> Signed-off-by: Karthik Nayak <karthik.188@xxxxxxxxx>
> Signed-off-by: Toon Claes <toon@xxxxxxxxx>
> Co-authored-by: toon@xxxxxxxxx
> ---
> Documentation/git-check-attr.txt | 10 +++-
> archive.c | 2 +-
> attr.c | 97 +++++++++++++++++++++++---------
> attr.h | 5 +-
> builtin/check-attr.c | 35 +++++++-----
> builtin/pack-objects.c | 2 +-
> convert.c | 2 +-
> ll-merge.c | 4 +-
> pathspec.c | 2 +-
> t/t0003-attributes.sh | 42 +++++++++++++-
> userdiff.c | 2 +-
> ws.c | 2 +-
> 12 files changed, 152 insertions(+), 53 deletions(-)
>
> diff --git a/Documentation/git-check-attr.txt b/Documentation/git-check-attr.txt
> index 84f41a8e82..fb15c44598 100644
> --- a/Documentation/git-check-attr.txt
> +++ b/Documentation/git-check-attr.txt
> @@ -9,8 +9,8 @@ git-check-attr - Display gitattributes information
> SYNOPSIS
> --------
> [verse]
> -'git check-attr' [-a | --all | <attr>...] [--] <pathname>...
> -'git check-attr' --stdin [-z] [-a | --all | <attr>...]
> +'git check-attr' [--source <tree>] [-a | --all | <attr>...] [--] <pathname>...
> +'git check-attr' --stdin [-z] [--source <tree>] [-a | --all | <attr>...]
>
> DESCRIPTION
> -----------
> @@ -36,6 +36,12 @@ OPTIONS
> If `--stdin` is also given, input paths are separated
> with a NUL character instead of a linefeed character.
>
> +--source=<tree>::
> + Check attributes against the specified tree-ish. Paths provided as part
> + of the revision will be treated as the root directory. It is common to
> + specify the source tree by naming a commit, branch or tag associated
> + with it.
> +
> \--::
> Interpret all preceding arguments as attributes and all following
> arguments as path names.
> diff --git a/archive.c b/archive.c
> index 941495f5d7..81ff76fce9 100644
> --- a/archive.c
> +++ b/archive.c
> @@ -120,7 +120,7 @@ static const struct attr_check *get_archive_attrs(struct index_state *istate,
> static struct attr_check *check;
> if (!check)
> check = attr_check_initl("export-ignore", "export-subst", NULL);
> - git_check_attr(istate, path, check);
> + git_check_attr(istate, NULL, path, check);
> return check;
> }
>
> diff --git a/attr.c b/attr.c
> index 42ad6de8c7..a63f267187 100644
> --- a/attr.c
> +++ b/attr.c
> @@ -13,6 +13,8 @@
> #include "dir.h"
> #include "utf8.h"
> #include "quote.h"
> +#include "revision.h"
> +#include "object-store.h"
> #include "thread-utils.h"
>
> const char git_attr__true[] = "(builtin)true";
> @@ -729,14 +731,62 @@ static struct attr_stack *read_attr_from_file(const char *path, unsigned flags)
> return res;
> }
>
> -static struct attr_stack *read_attr_from_index(struct index_state *istate,
> - const char *path,
> - unsigned flags)
> +static struct attr_stack *read_attr_from_buf(char *buf, const char *path,
> + unsigned flags)
> {
> struct attr_stack *res;
> - char *buf, *sp;
> + char *sp;
> int lineno = 0;
>
> + if (!buf)
> + return NULL;
> +
> + CALLOC_ARRAY(res, 1);
> + for (sp = buf; *sp;) {
> + char *ep;
> + int more;
> +
> + ep = strchrnul(sp, '\n');
> + more = (*ep == '\n');
> + *ep = '\0';
> + handle_attr_line(res, sp, path, ++lineno, flags);
> + sp = ep + more;
> + }
> + free(buf);
> +
> + return res;
> +}
> +
> +static struct attr_stack *read_attr_from_blob(struct index_state *istate,
> + const struct object_id *tree_oid,
> + const char *path, unsigned flags)
> +{
> + struct object_id oid;
> + unsigned long sz;
> + enum object_type type;
> + void *buf;
> + unsigned short mode;
> +
> + if (!tree_oid)
> + return NULL;
> +
> + if (get_tree_entry(istate->repo, tree_oid, path, &oid, &mode))
> + return NULL;
> +
> + buf = read_object_file(&oid, &type, &sz);
> + if (!buf || type != OBJ_BLOB) {
> + free(buf);
> + return NULL;
> + }
> +
> + return read_attr_from_buf(buf, path, flags);
> +}
> +
> +static struct attr_stack *read_attr_from_index(struct index_state *istate,
> + const char *path, unsigned flags)
> +{
> + char *buf;
> +
> if (!istate)
> return NULL;
>
> @@ -758,28 +808,19 @@ static struct attr_stack *read_attr_from_index(struct index_state *istate,
> if (!buf)
> return NULL;
>
> - CALLOC_ARRAY(res, 1);
> - for (sp = buf; *sp; ) {
> - char *ep;
> - int more;
> -
> - ep = strchrnul(sp, '\n');
> - more = (*ep == '\n');
> - *ep = '\0';
> - handle_attr_line(res, sp, path, ++lineno, flags);
> - sp = ep + more;
> - }
> - free(buf);
> - return res;
> + return read_attr_from_buf(buf, path, flags);
> }
>
> static struct attr_stack *read_attr(struct index_state *istate,
> + const struct object_id *tree_oid,
> const char *path, unsigned flags)
> {
> struct attr_stack *res = NULL;
>
> if (direction == GIT_ATTR_INDEX) {
> res = read_attr_from_index(istate, path, flags);
> + } else if (tree_oid) {
> + res = read_attr_from_blob(istate, tree_oid, path, flags);
> } else if (!is_bare_repository()) {
> if (direction == GIT_ATTR_CHECKOUT) {
> res = read_attr_from_index(istate, path, flags);
> @@ -839,6 +880,7 @@ static void push_stack(struct attr_stack **attr_stack_p,
> }
>
> static void bootstrap_attr_stack(struct index_state *istate,
> + const struct object_id *tree_oid,
> struct attr_stack **stack)
> {
> struct attr_stack *e;
> @@ -864,7 +906,7 @@ static void bootstrap_attr_stack(struct index_state *istate,
> }
>
> /* root directory */
> - e = read_attr(istate, GITATTRIBUTES_FILE, flags | READ_ATTR_NOFOLLOW);
> + e = read_attr(istate, tree_oid, GITATTRIBUTES_FILE, flags | READ_ATTR_NOFOLLOW);
> push_stack(stack, e, xstrdup(""), 0);
>
> /* info frame */
> @@ -878,6 +920,7 @@ static void bootstrap_attr_stack(struct index_state *istate,
> }
>
> static void prepare_attr_stack(struct index_state *istate,
> + const struct object_id *tree_oid,
> const char *path, int dirlen,
> struct attr_stack **stack)
> {
> @@ -899,7 +942,7 @@ static void prepare_attr_stack(struct index_state *istate,
> * .gitattributes in deeper directories to shallower ones,
> * and finally use the built-in set as the default.
> */
> - bootstrap_attr_stack(istate, stack);
> + bootstrap_attr_stack(istate, tree_oid, stack);
>
> /*
> * Pop the "info" one that is always at the top of the stack.
> @@ -954,7 +997,7 @@ static void prepare_attr_stack(struct index_state *istate,
> strbuf_add(&pathbuf, path + pathbuf.len, (len - pathbuf.len));
> strbuf_addf(&pathbuf, "/%s", GITATTRIBUTES_FILE);
>
> - next = read_attr(istate, pathbuf.buf, READ_ATTR_NOFOLLOW);
> + next = read_attr(istate, tree_oid, pathbuf.buf, READ_ATTR_NOFOLLOW);
>
> /* reset the pathbuf to not include "/.gitattributes" */
> strbuf_setlen(&pathbuf, len);
> @@ -1074,8 +1117,8 @@ static void determine_macros(struct all_attrs_item *all_attrs,
> * Otherwise all attributes are collected.
> */
> static void collect_some_attrs(struct index_state *istate,
> - const char *path,
> - struct attr_check *check)
> + const struct object_id *tree_oid,
> + const char *path, struct attr_check *check)
> {
> int pathlen, rem, dirlen;
> const char *cp, *last_slash = NULL;
> @@ -1094,7 +1137,7 @@ static void collect_some_attrs(struct index_state *istate,
> dirlen = 0;
> }
>
> - prepare_attr_stack(istate, path, dirlen, &check->stack);
> + prepare_attr_stack(istate, tree_oid, path, dirlen, &check->stack);
> all_attrs_init(&g_attr_hashmap, check);
> determine_macros(check->all_attrs, check->stack);
>
> @@ -1103,12 +1146,12 @@ static void collect_some_attrs(struct index_state *istate,
> }
>
> void git_check_attr(struct index_state *istate,
> - const char *path,
> + const struct object_id *tree_oid, const char *path,
> struct attr_check *check)
> {
> int i;
>
> - collect_some_attrs(istate, path, check);
> + collect_some_attrs(istate, tree_oid, path, check);
>
> for (i = 0; i < check->nr; i++) {
> size_t n = check->items[i].attr->attr_nr;
> @@ -1119,13 +1162,13 @@ void git_check_attr(struct index_state *istate,
> }
> }
>
> -void git_all_attrs(struct index_state *istate,
> +void git_all_attrs(struct index_state *istate, const struct object_id *tree_oid,
> const char *path, struct attr_check *check)
> {
> int i;
>
> attr_check_reset(check);
> - collect_some_attrs(istate, path, check);
> + collect_some_attrs(istate, tree_oid, path, check);
>
> for (i = 0; i < check->all_attrs_nr; i++) {
> const char *name = check->all_attrs[i].attr->name;
> diff --git a/attr.h b/attr.h
> index 3fb40cced0..84a3279215 100644
> --- a/attr.h
> +++ b/attr.h
> @@ -190,13 +190,14 @@ void attr_check_free(struct attr_check *check);
> const char *git_attr_name(const struct git_attr *);
>
> void git_check_attr(struct index_state *istate,
> - const char *path, struct attr_check *check);
> + const struct object_id *tree_oid, const char *path,
> + struct attr_check *check);
FYI, this breaks "make hdr-check".
> /*
> * Retrieve all attributes that apply to the specified path.
> * check holds the attributes and their values.
> */
> -void git_all_attrs(struct index_state *istate,
> +void git_all_attrs(struct index_state *istate, const struct object_id *tree_oid,
> const char *path, struct attr_check *check);
Likewise.
Perhaps squash something like this in in the next iteration?
attr.h | 1 +
1 file changed, 1 insertion(+)
diff --git i/attr.h w/attr.h
index 84a3279215..fca6c30430 100644
--- i/attr.h
+++ w/attr.h
@@ -108,6 +108,7 @@
*/
struct index_state;
+struct object_id;
/**
* An attribute is an opaque object that is identified by its name. Pass the
