use exceptionStr() when formating some errors in the logging code

Summary:
If an error is thrown when formating arguments for a log message, use
`folly::exceptionStr()` to format the exception instead of just `ex.what()`.

I changed all of the tests that verify the results of these strings to use a
regular expression, as `folly::exceptionStr()` produces different results in
different platforms, and does not always demangle type names.

I also included a minor change to increase a timeout in
AsyncFileWriterTest.cpp, as I saw this timeout fail spuriously once in my
testing.

Reviewed By: yfeldblum

Differential Revision: D21635680

fbshipit-source-id: 749ef48deb59af1f2faef0158e0291838e09fc38

folly/logging/LogStreamProcessor.h

@@ -19,6 +19,7 @@
 #include <fmt/core.h>
 #include <folly/CPortability.h>
 #include <folly/Conv.h>
+#include <folly/ExceptionString.h>
 #include <folly/Portability.h>
 #include <folly/lang/Exception.h>
 #include <folly/logging/LogCategory.h>
@@ -333,7 +334,7 @@ class LogStreamProcessor {
           // Just log an error message letting indicating that something went
           // wrong formatting the log message.
           return folly::to<std::string>(
-              "error constructing log message: ", ex.what());
+              "error constructing log message: ", exceptionStr(ex));
         });
   }
 
@@ -356,7 +357,7 @@ class LogStreamProcessor {
           failed = true;
           std::string result;
           result.append("error formatting log message: ");
-          result.append(ex.what());
+          result.append(exceptionStr(ex).c_str());
           result.append("; format string: \"");
           result.append(fmt.data(), fmt.size());
           result.append("\", arguments: ");

folly/logging/test/AsyncFileWriterTest.cpp

@@ -258,7 +258,7 @@ TEST(AsyncFileWriter, flush) {
   EXPECT_EQ(bytesRead, paddingSize);
 
   // Make sure flush completes successfully now
-  std::move(future).get(10ms);
+  std::move(future).get(50ms);
 }
 
 // A large-ish message suffix, just to consume space and help fill up

folly/logging/test/LoggerTest.cpp

@@ -111,12 +111,12 @@ TEST_F(LoggerTest, formatError) {
   ASSERT_EQ(1, messages.size());
   // Use a regex match here, since the type IDs are reported slightly
   // differently on different platforms.
-  EXPECT_EQ(
-      R"(error formatting log message: )"
-      R"(invalid type specifier; )"
-      R"(format string: "param1: {:06d}, param2: {:6.3f}", )"
-      R"(arguments: 1234, hello world!)",
-      messages[0].first.getMessage());
+  EXPECT_THAT(
+      messages[0].first.getMessage(),
+      MatchesRegex(R"(error formatting log message: )"
+                   R"(.*invalid type specifier; )"
+                   R"(format string: "param1: \{:06d\}, param2: \{:6.3f\}", )"
+                   R"(arguments: 1234, hello world!)"));
   EXPECT_EQ("LoggerTest.cpp", pathBasename(messages[0].first.getFileName()));
   EXPECT_EQ(LogLevel::WARN, messages[0].first.getLevel());
   EXPECT_FALSE(messages[0].first.containsNewlines());
@@ -185,10 +185,10 @@ TEST_F(LoggerTest, toStringError) {
 
   auto& messages = handler_->getMessages();
   ASSERT_EQ(1, messages.size());
-  EXPECT_EQ(
-      "error constructing log message: "
-      "error converting ToStringFailure object to a string",
-      messages[0].first.getMessage());
+  EXPECT_THAT(
+      messages[0].first.getMessage(),
+      MatchesRegex("error constructing log message: .*"
+                   "error converting ToStringFailure object to a string"));
   EXPECT_EQ("LoggerTest.cpp", pathBasename(messages[0].first.getFileName()));
   EXPECT_EQ(expectedLine, messages[0].first.getLineNumber());
   EXPECT_EQ(LogLevel::DBG1, messages[0].first.getLevel());
@@ -207,7 +207,7 @@ TEST_F(LoggerTest, formatFallbackError) {
   EXPECT_THAT(
       messages[0].first.getMessage(),
       MatchesRegex(
-          R"(error formatting log message: argument index out of range; )"
+          R"(error formatting log message: .*argument index out of range; )"
           R"(format string: "param1: \{\}, param2: \{\}, \{\}", )"
           R"(arguments: 1234, )"
           R"(\[(.*ToStringFailure.*|object) of size (.*):.*\])"));
@@ -225,7 +225,7 @@ TEST_F(LoggerTest, formatFallbackUnsupported) {
 
   std::string objectHex = kIsLittleEndian ? "ef cd 34 12" : "12 34 cd ef";
   auto expectedRegex =
-      R"(error formatting log message: test; )"
+      R"(error formatting log message: .*test; )"
       R"(format string: "param1: \{\}, param2: \{\}", )"
       R"(arguments: 1234, )"
       R"(\[(.*FormattableButNoToString.*|object) of size 4: )" +
@@ -343,10 +343,11 @@ TEST_F(LoggerTest, logMacros) {
   // Bad format arguments should not throw
   FB_LOGF(footest1234, ERR, "whoops: {}, {}", getValue());
   ASSERT_EQ(1, messages.size());
-  EXPECT_EQ(
-      R"(error formatting log message: argument index out of range; )"
-      R"(format string: "whoops: {}, {}", arguments: 5)",
-      messages[0].first.getMessage());
+  EXPECT_THAT(
+      messages[0].first.getMessage(),
+      MatchesRegex(
+          R"(error formatting log message: .*argument index out of range; )"
+          R"(format string: "whoops: \{\}, \{\}", arguments: 5)"));
   messages.clear();
 }