showTrace flag for ErrorInfo; showTrace test.

src/libmain/shared.cc

@@ -303,6 +303,7 @@ int handleExceptions(const string & programName, std::function<void()> fun)
     ReceiveInterrupts receiveInterrupts; // FIXME: need better place for this
 
     ErrorInfo::programName = baseNameOf(programName);
+    ErrorInfo::showTrace = settings.showTrace;
 
     string error = ANSI_RED "error:" ANSI_NORMAL " ";
     try {
@@ -323,9 +324,6 @@ int handleExceptions(const string & programName, std::function<void()> fun)
         printError("Try '%1% --help' for more information.", programName);
         return 1;
     } catch (BaseError & e) {
-        // TODO showTrace as argument, or have calcWhat check settings?
-        // if (settings.showTrace && e.prefix() != "")
-        //     printError(e.prefix());
         logError(e.info());
         // TODO fix to detect non-empty trace here.
         if (e.hasTrace() && !settings.showTrace)

src/libutil/error.cc

@@ -34,6 +34,7 @@ const string& BaseError::calcWhat() const
 }
 
 std::optional<string> ErrorInfo::programName = std::nullopt;
+bool ErrorInfo::showTrace = false;
 
 std::ostream& operator<<(std::ostream &os, const hintformat &hf)
 {
@@ -325,6 +326,7 @@ std::ostream& operator<<(std::ostream &out, const ErrorInfo &einfo)
     }
 
     // traces
+    if (ErrorInfo::showTrace) {
         for (auto iter = einfo.traces.rbegin(); iter != einfo.traces.rend(); ++iter)
         {
             try {
@@ -363,6 +365,7 @@ std::ostream& operator<<(std::ostream &out, const ErrorInfo &einfo)
                 out << iter->hint.str() << std::endl;
             }
         }
+    }
 
     return out;
 }

src/libutil/error.hh

@@ -107,6 +107,7 @@ struct ErrorInfo {
     std::list<Trace> traces;
 
     static std::optional<string> programName;
+    static bool showTrace;
 };
 
 std::ostream& operator<<(std::ostream &out, const ErrorInfo &einfo);

src/libutil/tests/logging.cc

@@ -251,6 +251,7 @@ namespace nix {
 
     TEST(addTrace, showTracesWithShowTrace) {
         SymbolTable testTable;
+        ErrorInfo::showTrace = true;
         auto problem_file = testTable.create(test_file);
 
         auto oneliner_file = testTable.create(one_liner);
@@ -272,6 +273,30 @@ namespace nix {
         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 command line argument\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 output ---\nwhile 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     1| this is the other problem line of code\n      |                   \x1B[31;1m^\x1B[0m\n");
     }
 
+    TEST(addTrace, hideTracesWithoutShowTrace) {
+        SymbolTable testTable;
+        ErrorInfo::showTrace = false;
+        auto problem_file = testTable.create(test_file);
+
+        auto oneliner_file = testTable.create(one_liner);
+
+        auto e = AssertionError(ErrorInfo {
+                .name = "wat",
+                .description = "a well-known problem occurred",
+                .hint = hintfmt("it has been %1% days since our last error", "zero"),
+                .errPos = Pos(foString, problem_file, 2, 13),
+            });
+
+        e.addTrace(Pos(foStdin, oneliner_file, 1, 19), "while trying to compute %1%", 42);
+
+        testing::internal::CaptureStderr();
+
+        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 command line argument\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");
+    }
+
     /* ----------------------------------------------------------------------------
      * hintfmt
      * --------------------------------------------------------------------------*/