From 2a39c083dca8f672c695898d56cf62081ac79eca Mon Sep 17 00:00:00 2001
From: Ben Burdette <bburdette@gmail.com>
Date: Wed, 1 Jul 2020 10:37:31 -0600
Subject: [PATCH] non-pos trace test

---
 src/libutil/error.cc         | 24 ++++++++++++++----------
 src/libutil/logging.cc       |  1 +
 src/libutil/tests/logging.cc |  4 +++-
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/src/libutil/error.cc b/src/libutil/error.cc
index 6b6b268a2..78e2a5ea2 100644
--- a/src/libutil/error.cc
+++ b/src/libutil/error.cc
@@ -187,6 +187,7 @@ void printCodeLines(std::ostream &out,
 
 void printAtPos(const string &prefix, const ErrPos &pos, std::ostream &out)
 {
+    if (pos)
     {
         switch (pos.origin) {
             case foFile: {
@@ -290,7 +291,7 @@ std::ostream& showErrorInfo(std::ostream &out, const ErrorInfo &einfo, bool show
             einfo.programName.value_or(""));
 
     bool nl = false;  // intersperse newline between sections.
-    if (einfo.errPos.has_value()) {
+    if (einfo.errPos.has_value() && (*einfo.errPos)) {
         out << prefix << std::endl;
         printAtPos(prefix, *einfo.errPos, out);
         nl = true;
@@ -355,17 +356,20 @@ std::ostream& showErrorInfo(std::ostream &out, const ErrorInfo &einfo, bool show
         {
             try {
                 out << std::endl << prefix;
-                out << ANSI_BLUE << "trace: " << ANSI_NORMAL << iter->hint.str() <<  std::endl;
+                out << ANSI_BLUE << "trace: " << ANSI_NORMAL << iter->hint.str();
 
-                auto pos = *iter->pos;
-                printAtPos(prefix, pos, out);
                 nl = true;
-                auto loc = getCodeLines(pos);
-                if (loc.has_value())
-                {
-                    out << std::endl;
-                    printCodeLines(out, prefix, pos, *loc);
-                    out << std::endl;
+                auto pos = *iter->pos;
+                if (pos) {
+                    out << std::endl << prefix;
+                    printAtPos(prefix, pos, out);
+                    auto loc = getCodeLines(pos);
+                    if (loc.has_value())
+                    {
+                        out << std::endl << prefix;
+                        printCodeLines(out, prefix, pos, *loc);
+                        out << std::endl << prefix;
+                    }
                 }
             } catch(const std::bad_optional_access& e) {
                 out << iter->hint.str() << std::endl;
diff --git a/src/libutil/logging.cc b/src/libutil/logging.cc
index 504f5fb52..7a58527b8 100644
--- a/src/libutil/logging.cc
+++ b/src/libutil/logging.cc
@@ -84,6 +84,7 @@ public:
 
         log(ei.level, oss.str());
     }
+    
 
     void startActivity(ActivityId act, Verbosity lvl, ActivityType type,
         const std::string & s, const Fields & fields, ActivityId parent)
diff --git a/src/libutil/tests/logging.cc b/src/libutil/tests/logging.cc
index a73c1f8d9..4ebc3a3bf 100644
--- a/src/libutil/tests/logging.cc
+++ b/src/libutil/tests/logging.cc
@@ -263,6 +263,7 @@ namespace nix {
             });
 
         e.addTrace(Pos(foStdin, oneliner_file, 1, 19), "while trying to compute %1%", 42);
+        e.addTrace(std::nullopt, "while doing something without a %1%", "pos");
 
         testing::internal::CaptureStderr();
 
@@ -271,7 +272,7 @@ namespace nix {
         logError(e.info());
 
         auto str = testing::internal::GetCapturedStderr();
-        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- AssertionError --- error-unit-test\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(2:13)\x1B[34;1m from string\x1B[0m\n\na well-known problem occurred\n\n     1| previous line of code\n     2| this is the problem line of code\n      |             \x1B[31;1m^\x1B[0m\n     3| next line of code\n\nit has been \x1B[33;1mzero\x1B[0m days since our last error\n\x1B[34;1m---- show-trace ----\x1B[0m\n\x1B[34;1mtrace: \x1B[0mwhile trying to compute \x1B[33;1m42\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(1:19)\x1B[34;1m from stdin\x1B[0m\n\n     1| this is the other problem line of code\n      |                   \x1B[31;1m^\x1B[0m\n\n");
+        ASSERT_STREQ(str.c_str(), "\x1B[31;1merror:\x1B[0m\x1B[34;1m --- AssertionError --- error-unit-test\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(2:13)\x1B[34;1m from string\x1B[0m\n\na well-known problem occurred\n\n     1| previous line of code\n     2| this is the problem line of code\n      |             \x1B[31;1m^\x1B[0m\n     3| next line of code\n\nit has been \x1B[33;1mzero\x1B[0m days since our last error\n\x1B[34;1m---- show-trace ----\x1B[0m\n\x1B[34;1mtrace: \x1B[0mwhile trying to compute \x1B[33;1m42\x1B[0m\n\x1B[34;1mat: \x1B[33;1m(1:19)\x1B[34;1m from stdin\x1B[0m\n\n     1| this is the other problem line of code\n      |                   \x1B[31;1m^\x1B[0m\n\n\x1B[34;1mtrace: \x1B[0mwhile doing something without a \x1B[33;1mpos\x1B[0m\n");
     }
 
     TEST(addTrace, hideTracesWithoutShowTrace) {
@@ -288,6 +289,7 @@ namespace nix {
             });
 
         e.addTrace(Pos(foStdin, oneliner_file, 1, 19), "while trying to compute %1%", 42);
+        e.addTrace(std::nullopt, "while doing something without a %1%", "pos");
 
         testing::internal::CaptureStderr();