Stop storing is_breakpoint inside the parser

This can also be trivially computed from the block list.

src/builtin_status.cpp

@@ -414,7 +414,7 @@ maybe_t<int> builtin_status(parser_t &parser, io_streams_t &streams, const wchar
         }
         case STATUS_IS_BREAKPOINT: {
             CHECK_FOR_UNEXPECTED_STATUS_ARGS(opts.status_cmd)
-            retval = parser.libdata().is_breakpoint ? 0 : 1;
+            retval = parser.is_breakpoint() ? 0 : 1;
             break;
         }
         case STATUS_IS_LOGIN: {

src/parser.cpp

@@ -136,10 +136,6 @@ block_t *parser_t::push_block(block_t &&block) {
         new_current.src_filename = intern(filename);
     }
 
-    if (type == block_type_t::breakpoint) {
-        libdata().is_breakpoint = true;
-    }
-
     if (new_current.type() != block_type_t::top) {
         bool shadow = (type == block_type_t::function_call);
         vars().push(shadow);
@@ -161,16 +157,6 @@ void parser_t::pop_block(const block_t *expected) {
     block_list.pop_front();
 
     if (old.wants_pop_env) vars().pop();
-
-    // Are we still in a breakpoint?
-    bool new_is_breakpoint = false;
-    for (const auto &b : block_list) {
-        if (b.type() == block_type_t::breakpoint) {
-            new_is_breakpoint = true;
-            break;
-        }
-    }
-    libdata().is_breakpoint = new_is_breakpoint;
 }
 
 const wchar_t *parser_t::get_block_desc(block_type_t block) {
@@ -419,6 +405,15 @@ bool parser_t::is_block() const {
     return false;
 }
 
+bool parser_t::is_breakpoint() const {
+    for (const auto &b : block_list) {
+        if (b.type() == block_type_t::breakpoint) {
+            return true;
+        }
+    }
+    return false;
+}
+
 maybe_t<wcstring> parser_t::get_function_name(int level) {
     if (level == 0) {
         // Return the function name for the level preceding the most recent breakpoint. If there

src/parser.h

@@ -169,9 +169,6 @@ struct library_data_t {
     /// Whether we are running a subshell command.
     bool is_subshell{false};
 
-    /// Whether we are running due to a `breakpoint` command.
-    bool is_breakpoint{false};
-
     /// Whether we are running an event handler. This is not a bool because we keep count of the
     /// event nesting level.
     int is_event{0};
@@ -341,6 +338,9 @@ class parser_t : public std::enable_shared_from_this<parser_t> {
     /// This supports 'status is-block'.
     bool is_block() const;
 
+    /// \return whether we have a breakpoint block.
+    bool is_breakpoint() const;
+
     /// Returns the block at the given index. 0 corresponds to the innermost block. Returns nullptr
     /// when idx is at or equal to the number of blocks.
     const block_t *block_at_index(size_t idx) const;

src/reader.cpp

@@ -2747,7 +2747,7 @@ static int read_i(parser_t &parser) {
     conf.autosuggest_ok = true;
     conf.expand_abbrev_ok = true;
 
-    if (parser.libdata().is_breakpoint && function_exists(DEBUG_PROMPT_FUNCTION_NAME, parser)) {
+    if (parser.is_breakpoint() && function_exists(DEBUG_PROMPT_FUNCTION_NAME, parser)) {
         conf.left_prompt_cmd = DEBUG_PROMPT_FUNCTION_NAME;
         conf.right_prompt_cmd = wcstring{};
     } else {