From e640a01ea5a1789e8ea69110e93073dabd786622 Mon Sep 17 00:00:00 2001
From: ridiculousfish <corydoras@ridiculousfish.com>
Date: Wed, 22 Jan 2020 11:58:10 -0800
Subject: [PATCH] Express cancellation as a possible result of expand_string

This allows us to properly thread control-C signals from command
substitutions into the expanding string.
---
 src/complete.cpp        | 3 +++
 src/expand.cpp          | 6 +++++-
 src/expand.h            | 2 ++
 src/parse_execution.cpp | 9 +++++++++
 4 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/complete.cpp b/src/complete.cpp
index 67d1522d2..088c0ec47 100644
--- a/src/complete.cpp
+++ b/src/complete.cpp
@@ -680,6 +680,9 @@ void completer_t::complete_cmd(const wcstring &str_cmd) {
                       this->expand_flags() | expand_flag::special_for_command |
                           expand_flag::for_completions | expand_flag::executables_only,
                       ctx);
+    if (result == expand_result_t::cancel) {
+        return;
+    }
     if (result != expand_result_t::error && this->wants_descriptions()) {
         this->complete_cmd_desc(str_cmd);
     }
diff --git a/src/expand.cpp b/src/expand.cpp
index 3cb203e6e..990295037 100644
--- a/src/expand.cpp
+++ b/src/expand.cpp
@@ -1012,7 +1012,7 @@ expand_result_t expander_t::stage_wildcards(wcstring path_to_expand, completion_
                 case wildcard_expand_result_t::no_match:
                     break;
                 case wildcard_expand_result_t::cancel:
-                    result = expand_result_t::error;
+                    result = expand_result_t::cancel;
                     break;
             }
         }
@@ -1055,6 +1055,10 @@ expand_result_t expander_t::expand_string(wcstring input, completion_list_t *out
     expand_result_t total_result = expand_result_t::ok;
     for (stage_t stage : stages) {
         for (completion_t &comp : completions) {
+            if (ctx.check_cancel()) {
+                total_result = expand_result_t::cancel;
+                break;
+            }
             expand_result_t this_result =
                 (expand.*stage)(std::move(comp.completion), &output_storage);
             total_result = this_result;
diff --git a/src/expand.h b/src/expand.h
index 5b396c711..8aa2915cc 100644
--- a/src/expand.h
+++ b/src/expand.h
@@ -105,6 +105,8 @@ enum class expand_result_t {
     error,
     /// Expansion succeeded.
     ok,
+    /// Expansion was cancelled (e.g. control-C).
+    cancel,
     /// Expansion succeeded, but a wildcard in the string matched no files,
     /// so the output is empty.
     wildcard_no_match,
diff --git a/src/parse_execution.cpp b/src/parse_execution.cpp
index 5f0de0765..f60d9d61f 100644
--- a/src/parse_execution.cpp
+++ b/src/parse_execution.cpp
@@ -465,6 +465,9 @@ eval_result_t parse_execution_context_t::run_switch_statement(
         case expand_result_t::error:
             return report_errors(errors);
 
+        case expand_result_t::cancel:
+            return eval_result_t::cancelled;
+
         case expand_result_t::wildcard_no_match:
             return report_unmatched_wildcard_error(switch_value_n);
 
@@ -874,6 +877,9 @@ eval_result_t parse_execution_context_t::expand_arguments_from_nodes(
             case expand_result_t::error: {
                 return this->report_errors(errors);
             }
+            case expand_result_t::cancel: {
+                return eval_result_t::cancelled;
+            }
             case expand_result_t::wildcard_no_match: {
                 if (glob_behavior == failglob) {
                     // Report the unmatched wildcard error and stop processing.
@@ -1023,6 +1029,9 @@ eval_result_t parse_execution_context_t::apply_variable_assignments(
                 this->report_errors(errors);
                 return eval_result_t::error;
             }
+            case expand_result_t::cancel: {
+                return eval_result_t::cancelled;
+            }
             case expand_result_t::wildcard_no_match:  // nullglob (equivalent to set)
             case expand_result_t::ok: {
                 break;