environment: stop storing "core.warnAmbiguousRefs" globally

Same as the preceding commits, storing the "core.warnAmbiguousRefs"
value globally is misdesigned as this setting may be set per repository.

Move the logic into the repo-settings subsystem. The usual pattern here
is that users are expected to call `prepare_repo_settings()` before they
access the settings themselves. This seems somewhat fragile though, as
it is easy to miss and leads to somewhat ugly code patterns at the call
sites.

Instead, introduce a new function that encapsulates this logic for us.
This also allows us to change how exactly the lazy initialization works
in the future, e.g. by only partially initializing values as requested
by the caller.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/rev-parse.c

@@ -19,6 +19,7 @@
 #include "path.h"
 #include "diff.h"
 #include "read-cache-ll.h"
+#include "repo-settings.h"
 #include "repository.h"
 #include "revision.h"
 #include "setup.h"
@@ -899,7 +900,8 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 			}
 			if (opt_with_value(arg, "--abbrev-ref", &arg)) {
 				abbrev_ref = 1;
-				abbrev_ref_strict = warn_ambiguous_refs;
+				abbrev_ref_strict =
+					repo_settings_get_warn_ambiguous_refs(the_repository);
 				if (arg) {
 					if (!strcmp(arg, "strict"))
 						abbrev_ref_strict = 1;

config.c

@@ -1447,11 +1447,6 @@ static int git_default_core_config(const char *var, const char *value,
 		return 0;
 	}
 
-	if (!strcmp(var, "core.warnambiguousrefs")) {
-		warn_ambiguous_refs = git_config_bool(var, value);
-		return 0;
-	}
-
 	if (!strcmp(var, "core.abbrev")) {
 		if (!value)
 			return config_error_nonbool(var);

environment.c

@@ -35,7 +35,6 @@ int minimum_abbrev = 4, default_abbrev = -1;
 int ignore_case;
 int assume_unchanged;
 int is_bare_repository_cfg = -1; /* unspecified */
-int warn_ambiguous_refs = 1;
 int warn_on_object_refname_ambiguity = 1;
 int repository_format_precious_objects;
 char *git_commit_encoding;

environment.h

@@ -156,7 +156,6 @@ extern int has_symlinks;
 extern int minimum_abbrev, default_abbrev;
 extern int ignore_case;
 extern int assume_unchanged;
-extern int warn_ambiguous_refs;
 extern int warn_on_object_refname_ambiguity;
 extern char *apply_default_whitespace;
 extern char *apply_default_ignorewhitespace;

object-name.c

@@ -20,6 +20,7 @@
 #include "pretty.h"
 #include "object-store-ll.h"
 #include "read-cache-ll.h"
+#include "repo-settings.h"
 #include "repository.h"
 #include "setup.h"
 #include "midx.h"
@@ -959,7 +960,7 @@ static int get_oid_basic(struct repository *r, const char *str, int len,
 	int fatal = !(flags & GET_OID_QUIETLY);
 
 	if (len == r->hash_algo->hexsz && !get_oid_hex(str, oid)) {
-		if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
+		if (repo_settings_get_warn_ambiguous_refs(r) && warn_on_object_refname_ambiguity) {
 			refs_found = repo_dwim_ref(r, str, len, &tmp_oid, &real_ref, 0);
 			if (refs_found > 0) {
 				warning(warn_msg, len, str);
@@ -1020,7 +1021,7 @@ static int get_oid_basic(struct repository *r, const char *str, int len,
 	if (!refs_found)
 		return -1;
 
-	if (warn_ambiguous_refs && !(flags & GET_OID_QUIETLY) &&
+	if (repo_settings_get_warn_ambiguous_refs(r) && !(flags & GET_OID_QUIETLY) &&
 	    (refs_found > 1 ||
 	     !get_short_oid(r, str, len, &tmp_oid, GET_OID_QUIETLY)))
 		warning(warn_msg, len, str);

ref-filter.c

@@ -13,6 +13,7 @@
 #include "object-name.h"
 #include "object-store-ll.h"
 #include "oid-array.h"
+#include "repo-settings.h"
 #include "repository.h"
 #include "commit.h"
 #include "mailmap.h"
@@ -2160,7 +2161,7 @@ static const char *show_ref(struct refname_atom *atom, const char *refname)
 	if (atom->option == R_SHORT)
 		return refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
 						    refname,
-						    warn_ambiguous_refs);
+						    repo_settings_get_warn_ambiguous_refs(the_repository));
 	else if (atom->option == R_LSTRIP)
 		return lstrip_ref_components(refname, atom->lstrip);
 	else if (atom->option == R_RSTRIP)

refs.c

@@ -730,7 +730,7 @@ int expand_ref(struct repository *repo, const char *str, int len,
 		if (r) {
 			if (!refs_found++)
 				*ref = xstrdup(r);
-			if (!warn_ambiguous_refs)
+			if (!repo_settings_get_warn_ambiguous_refs(repo))
 				break;
 		} else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
 			warning(_("ignoring dangling symref %s"), fullref.buf);
@@ -775,7 +775,7 @@ int repo_dwim_log(struct repository *r, const char *str, int len,
 			if (oid)
 				oidcpy(oid, &hash);
 		}
-		if (!warn_ambiguous_refs)
+		if (!repo_settings_get_warn_ambiguous_refs(r))
 			break;
 	}
 	strbuf_release(&path);

repo-settings.c

@@ -140,3 +140,12 @@ enum log_refs_config repo_settings_get_log_all_ref_updates(struct repository *re
 
 	return LOG_REFS_UNSET;
 }
+
+int repo_settings_get_warn_ambiguous_refs(struct repository *repo)
+{
+	prepare_repo_settings(repo);
+	if (repo->settings.warn_ambiguous_refs < 0)
+		repo_cfg_bool(repo, "core.warnambiguousrefs",
+			      &repo->settings.warn_ambiguous_refs, 1);
+	return repo->settings.warn_ambiguous_refs;
+}

repo-settings.h

@@ -56,16 +56,20 @@ struct repo_settings {
 	enum fetch_negotiation_setting fetch_negotiation_algorithm;
 
 	int core_multi_pack_index;
+	int warn_ambiguous_refs; /* lazily loaded via accessor */
 };
 #define REPO_SETTINGS_INIT { \
 	.index_version = -1, \
 	.core_untracked_cache = UNTRACKED_CACHE_KEEP, \
 	.fetch_negotiation_algorithm = FETCH_NEGOTIATION_CONSECUTIVE, \
+	.warn_ambiguous_refs = -1, \
 }
 
 void prepare_repo_settings(struct repository *r);
 
 /* Read the value for "core.logAllRefUpdates". */
 enum log_refs_config repo_settings_get_log_all_ref_updates(struct repository *repo);
+/* Read the value for "core.warnAmbiguousRefs". */
+int repo_settings_get_warn_ambiguous_refs(struct repository *repo);
 
 #endif /* REPO_SETTINGS_H */