From 1cf01a34eaccd6da613dba82291666db237916ab Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 21 Sep 2017 02:25:41 -0400 Subject: consistently use "fallthrough" comments in switches Gcc 7 adds -Wimplicit-fallthrough, which can warn when a switch case falls through to the next case. The general idea is that the compiler can't tell if this was intentional or not, so you should annotate any intentional fall-throughs as such, leaving it to complain about any unannotated ones. There's a GNU __attribute__ which can be used for annotation, but of course we'd have to #ifdef it away on non-gcc compilers. Gcc will also recognize specially-formatted comments, which matches our current practice. Let's extend that practice to all of the unannotated sites (which I did look over and verify that they were behaving as intended). Ideally in each case we'd actually give some reasons in the comment about why we're falling through, or what we're falling through to. And gcc does support that with -Wimplicit-fallthrough=2, which relaxes the comment pattern matching to anything that contains "fallthrough" (or a variety of spelling variants). However, this isn't the default for -Wimplicit-fallthrough, nor for -Wextra. In the name of simplicity, it's probably better for us to support the default level, which requires "fallthrough" to be the only thing in the comment (modulo some window dressing like "else" and some punctuation; see the gcc manual for the complete set of patterns). This patch suppresses all warnings due to -Wimplicit-fallthrough. We might eventually want to add that to the DEVELOPER Makefile knob, but we should probably wait until gcc 7 is more widely adopted (since earlier versions will complain about the unknown warning type). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano diff --git a/apply.c b/apply.c index 71cbbd1..c022af5 100644 --- a/apply.c +++ b/apply.c @@ -2920,6 +2920,7 @@ static int apply_one_fragment(struct apply_state *state, if (plen && (ws_rule & WS_BLANK_AT_EOF) && ws_blank_line(patch + 1, plen, ws_rule)) is_blank_context = 1; + /* fallthrough */ case '-': memcpy(old, patch + 1, plen); add_line_info(&preimage, old, plen, @@ -2927,7 +2928,7 @@ static int apply_one_fragment(struct apply_state *state, old += plen; if (first == '-') break; - /* Fall-through for ' ' */ + /* fallthrough */ case '+': /* --no-add does not add new lines */ if (first == '+' && state->no_add) diff --git a/builtin/cat-file.c b/builtin/cat-file.c index 4ccbfaa..aee280e 100644 --- a/builtin/cat-file.c +++ b/builtin/cat-file.c @@ -113,6 +113,7 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name, if (textconv_object(path, obj_context.mode, &oid, 1, &buf, &size)) break; + /* else fallthrough */ case 'p': type = sha1_object_info(oid.hash, NULL); diff --git a/builtin/checkout.c b/builtin/checkout.c index 5c202b7..d091f06 100644 --- a/builtin/checkout.c +++ b/builtin/checkout.c @@ -436,6 +436,7 @@ static int reset_tree(struct tree *tree, const struct checkout_opts *o, * update paths in the work tree, and we cannot revert * them. */ + /* fallthrough */ case 0: return 0; default: diff --git a/builtin/remote-ext.c b/builtin/remote-ext.c index bfb21ba..6a9127a 100644 --- a/builtin/remote-ext.c +++ b/builtin/remote-ext.c @@ -57,7 +57,7 @@ static char *strip_escapes(const char *str, const char *service, special = str[rpos]; if (rpos == 1) break; - /* Fall-through to error. */ + /* fallthrough */ default: die("Bad remote-ext placeholder '%%%c'.", str[rpos]); diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c index 818fe74..f6a5e1a 100644 --- a/builtin/submodule--helper.c +++ b/builtin/submodule--helper.c @@ -1189,6 +1189,7 @@ static int push_check(int argc, const char **argv, const char *prefix) break; die("HEAD does not match the named branch in the superproject"); } + /* fallthrough */ default: die("src refspec '%s' must name a ref", rs->src); diff --git a/config.c b/config.c index cd5a69e..08490df 100644 --- a/config.c +++ b/config.c @@ -2353,6 +2353,7 @@ static int store_write_pair(int fd, const char *key, const char *value) case '"': case '\\': strbuf_addch(&sb, '\\'); + /* fallthrough */ default: strbuf_addch(&sb, value[i]); break; diff --git a/convert.c b/convert.c index a09935c..20d7ab6 100644 --- a/convert.c +++ b/convert.c @@ -1545,8 +1545,9 @@ static int ident_filter_fn(struct stream_filter *filter, switch (ident->state) { default: strbuf_add(&ident->left, head, ident->state); + /* fallthrough */ case IDENT_SKIPPING: - /* fallthru */ + /* fallthrough */ case IDENT_DRAINING: ident_drain(ident, &output, osize_p); } diff --git a/fsck.c b/fsck.c index 2d2d2e9..2ad00fc 100644 --- a/fsck.c +++ b/fsck.c @@ -588,6 +588,7 @@ static int fsck_tree(struct tree *item, struct fsck_options *options) case S_IFREG | 0664: if (!options->strict) break; + /* fallthrough */ default: has_bad_modes = 1; } diff --git a/http-push.c b/http-push.c index e4c9b06..d860c47 100644 --- a/http-push.c +++ b/http-push.c @@ -1523,6 +1523,7 @@ static int remote_exists(const char *path) break; case HTTP_ERROR: error("unable to access '%s': %s", url, curl_errorstr); + /* fallthrough */ default: ret = -1; } diff --git a/mailinfo.c b/mailinfo.c index f2387a3..bcdbf98 100644 --- a/mailinfo.c +++ b/mailinfo.c @@ -822,6 +822,7 @@ static void handle_filter(struct mailinfo *mi, struct strbuf *line) if (!handle_commit_msg(mi, line)) break; mi->filter_stage++; + /* fallthrough */ case 1: handle_patch(mi, line); break; diff --git a/quote.c b/quote.c index 53b98a5..de2922d 100644 --- a/quote.c +++ b/quote.c @@ -431,6 +431,7 @@ void tcl_quote_buf(struct strbuf *sb, const char *src) case '{': case '}': case '$': case '\\': case '"': strbuf_addch(sb, '\\'); + /* fallthrough */ default: strbuf_addch(sb, c); break; diff --git a/read-cache.c b/read-cache.c index b211c57..a051567 100644 --- a/read-cache.c +++ b/read-cache.c @@ -220,6 +220,7 @@ static int ce_modified_check_fs(const struct cache_entry *ce, struct stat *st) case S_IFDIR: if (S_ISGITLINK(ce->ce_mode)) return ce_compare_gitlink(ce) ? DATA_CHANGED : 0; + /* else fallthrough */ default: return TYPE_CHANGED; } diff --git a/send-pack.c b/send-pack.c index b865f66..a8cc6b2 100644 --- a/send-pack.c +++ b/send-pack.c @@ -497,7 +497,7 @@ int send_pack(struct send_pack_args *args, strbuf_release(&cap_buf); return atomic_push_failure(args, remote_refs, ref); } - /* Fallthrough for non atomic case. */ + /* else fallthrough */ default: continue; } -- cgit v0.10.2-6-g49f6