Remove the last of the signal blocking and checks

fish's signal handlers are now sufficiently innocuous that there should
be no reason to block signals (outside of temporarily, when creating a
thread and we need to manipulate the signal mask).

src/autoload.cpp

@@ -63,7 +63,6 @@ int autoload_t::unload(const wcstring &cmd) { return this->evict_node(cmd); }
 
 int autoload_t::load(const wcstring &cmd, bool reload) {
     int res;
-    CHECK_BLOCK(0);
     ASSERT_IS_MAIN_THREAD();
 
     // TODO: Justify this principal_parser.

src/common.h

@@ -272,19 +272,6 @@ inline bool is_whitespace(const wchar_t *input) { return is_whitespace(wcstring(
 
 [[noreturn]] void __fish_assert(const char *msg, const char *file, size_t line, int error);
 
-/// Check if signals are blocked. If so, print an error message and return from the function
-/// performing this check.
-#define CHECK_BLOCK(retval)
-#if 0
-#define CHECK_BLOCK(retval)                                                \
-    if (signal_is_blocked()) {                                             \
-        debug(0, "function %s called while blocking signals. ", __func__); \
-        bugreport();                                                       \
-        show_stackframe(L'E');                                             \
-        return retval;                                                     \
-    }
-#endif
-
 /// Shorthand for wgettext call in situations where a C-style string is needed (e.g., fwprintf()).
 #define _(wstr) wgettext(wstr).c_str()
 

src/event.cpp

@@ -254,18 +254,6 @@ static void event_fire_internal(const event_t &event) {
         }
     }
 
-    // No matches. Time to return.
-    if (fire.empty()) return;
-
-    if (signal_is_blocked()) {
-        // Fix for #608. Don't run event handlers while signals are blocked.
-        input_common_add_callback([event]() {
-            ASSERT_IS_MAIN_THREAD();
-            event_fire(event);
-        });
-        return;
-    }
-
     // Iterate over our list of matching events. Fire the ones that are still present.
     for (const shared_ptr<event_handler_t> &handler : fire) {
         // Only fire if this event is still present

src/input.cpp

@@ -483,8 +483,6 @@ static wchar_t input_read_characters_only() {
 }
 
 wint_t input_readch(bool allow_commands) {
-    CHECK_BLOCK(R_NULL);
-
     // Clear the interrupted flag.
     reader_reset_interrupted();
     // Search for sequence in mapping tables.

src/parser.cpp

@@ -647,7 +647,6 @@ int parser_t::eval(wcstring cmd, const io_chain_t &io, enum block_type_t block_t
 }
 
 void parser_t::eval(parsed_source_ref_t ps, const io_chain_t &io, enum block_type_t block_type) {
-    CHECK_BLOCK(1);
     assert(block_type == TOP || block_type == SUBST);
     if (!ps->tree.empty()) {
         // Execute the first node.
@@ -662,8 +661,6 @@ int parser_t::eval_node(parsed_source_ref_t ps, tnode_t<T> node, const io_chain_
     static_assert(
         std::is_same<T, grammar::statement>::value || std::is_same<T, grammar::job_list>::value,
         "Unexpected node type");
-    CHECK_BLOCK(1);
-
     // Handle cancellation requests. If our block stack is currently empty, then we already did
     // successfully cancel (or there was nothing to cancel); clear the flag. If our block stack is
     // not empty, we are still in the process of cancelling; refuse to evaluate anything.

src/signal.cpp

@@ -29,9 +29,6 @@ struct lookup_entry {
     const wchar_t *desc;
 };
 
-/// The number of signal blocks in place. Increased by signal_block, decreased by signal_unblock.
-static int block_count = 0;
-
 /// Lookup table used to convert between signal names and signal ids, etc.
 static const struct lookup_entry signal_table[] = {
 #ifdef SIGHUP
@@ -413,19 +410,6 @@ void get_signals_with_handlers(sigset_t *set) {
     }
 }
 
-void signal_block() {
-    ASSERT_IS_MAIN_THREAD();
-    sigset_t chldset;
-
-    if (!block_count) {
-        sigfillset(&chldset);
-        DIE_ON_FAILURE(pthread_sigmask(SIG_BLOCK, &chldset, NULL));
-    }
-
-    block_count++;
-    // debug( 0, L"signal block level increased to %d", block_count );
-}
-
 /// Ensure we did not inherit any blocked signals. See issue #3964.
 void signal_unblock_all() {
     sigset_t iset;
@@ -433,21 +417,3 @@ void signal_unblock_all() {
     sigprocmask(SIG_SETMASK, &iset, NULL);
 }
 
-void signal_unblock() {
-    ASSERT_IS_MAIN_THREAD();
-
-    block_count--;
-    if (block_count < 0) {
-        debug(0, _(L"Signal block mismatch"));
-        bugreport();
-        FATAL_EXIT();
-    }
-
-    if (!block_count) {
-        sigset_t chldset;
-        sigfillset(&chldset);
-        DIE_ON_FAILURE(pthread_sigmask(SIG_UNBLOCK, &chldset, 0));
-    }
-}
-
-bool signal_is_blocked() { return static_cast<bool>(block_count); }

src/signal.h

@@ -29,15 +29,6 @@ void signal_handle(int sig, int do_handle);
 /// Ensure we did not inherit any blocked signals. See issue #3964.
 void signal_unblock_all();
 
-/// Block all signals.
-void signal_block();
-
-/// Unblock all signals.
-void signal_unblock();
-
-/// Returns true if signals are being blocked.
-bool signal_is_blocked();
-
 /// Returns signals with non-default handlers.
 void get_signals_with_handlers(sigset_t *set);