From 0b11b8cffbcfc2c2512227904ba666f929775b1a Mon Sep 17 00:00:00 2001
From: ridiculousfish <corydoras@ridiculousfish.com>
Date: Thu, 28 Mar 2019 20:22:58 -0700
Subject: [PATCH] Revert "Optimize identification of deferred process"

This reverts commit 4aea4c09b310e23ae5b06b9dd195ec8106dd6355.

Said commit broke many tests
---
 src/exec.cpp | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/src/exec.cpp b/src/exec.cpp
index 90bcd15d6..ddf612d9d 100644
--- a/src/exec.cpp
+++ b/src/exec.cpp
@@ -993,21 +993,21 @@ static bool exec_process_in_job(parser_t &parser, process_t *p, std::shared_ptr<
 // This should show the output as it comes, not buffer until the end.
 // Any such process (only one per job) will be called the "deferred" process.
 static process_t *get_deferred_process(const shared_ptr<job_t> &j) {
-    // By enumerating in reverse order, we can avoid walking the entire list
-    for (auto i = j->processes.rbegin(); i != j->processes.rend(); ++i) {
-        const auto &p = *i;
+    process_t *last_internal = nullptr;
+    for (const auto &p : j->processes) {
         if (p->type == process_type_t::exec) {
             // No tail reordering for execs.
             return nullptr;
         } else if (p->type != process_type_t::external) {
-            if (p->is_last_in_job) {
-                return nullptr;
-            }
-            debug(1, "Deferring execution of %ls", p->argv0());
-            return p.get();
+            last_internal = p.get();
         }
     }
-    return nullptr;
+    if (last_internal && !last_internal->is_last_in_job) {
+        // This is the last internal process, and it pipes to an external process.
+        return last_internal;
+    } else {
+        return nullptr;
+    }
 }
 
 bool exec_job(parser_t &parser, shared_ptr<job_t> j) {
@@ -1086,16 +1086,16 @@ bool exec_job(parser_t &parser, shared_ptr<job_t> j) {
             }
             pipe_next_read = std::move(pipes->read);
             proc_pipes.write = std::move(pipes->write);
-
-            // The deferred process can never be the last in the job
-            if (p.get() == deferred_process) {
-                deferred_pipes = std::move(proc_pipes);
-            }
         }
-        if (!exec_process_in_job(parser, p.get(), j, std::move(proc_pipes), all_ios, deferred_pipes,
-                                 stdout_read_limit)) {
-            exec_error = true;
-            break;
+
+        if (p.get() == deferred_process) {
+            deferred_pipes = std::move(proc_pipes);
+        } else {
+            if (!exec_process_in_job(parser, p.get(), j, std::move(proc_pipes), all_ios,
+                                     deferred_pipes, stdout_read_limit)) {
+                exec_error = true;
+                break;
+            }
         }
     }
     pipe_next_read.close();