From 7572a68eaa7a4f311c6545ca2cf84489f4a9ec84 Mon Sep 17 00:00:00 2001
From: Tim Stack <timothyshanestack@gmail.com>
Date: Tue, 15 Aug 2023 21:14:37 -0700
Subject: [PATCH] [date_time] do not change time format if there is a loss of
 precision

---
 src/log_format.cc         | 21 +++++++++++++++++++++
 src/logfile_sub_source.cc | 13 +++++++------
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/log_format.cc b/src/log_format.cc
index 8a12bb70..676b3ed0 100644
--- a/src/log_format.cc
+++ b/src/log_format.cc
@@ -72,6 +72,9 @@ external_log_format::mod_map_t external_log_format::MODULE_FORMATS;
 std::vector<std::shared_ptr<external_log_format>>
     external_log_format::GRAPH_ORDERED_FORMATS;
 
+static const uint32_t DATE_TIME_SET_FLAGS = ETF_YEAR_SET | ETF_MONTH_SET
+    | ETF_DAY_SET | ETF_HOUR_SET | ETF_MINUTE_SET | ETF_SECOND_SET;
+
 log_level_stats&
 log_level_stats::operator|=(const log_level_stats& rhs)
 {
@@ -643,8 +646,26 @@ log_format::log_scanf(uint32_t line_number,
                 auto ls = this->lf_date_time.unlock();
                 retval = this->lf_date_time.scan(
                     ts->data(), ts->length(), nullptr, tm_out, *tv_out);
+                if (retval != nullptr) {
+                    auto old_flags
+                        = this->lf_timestamp_flags & DATE_TIME_SET_FLAGS;
+                    auto new_flags = tm_out->et_flags & DATE_TIME_SET_FLAGS;
+
+                    // It is unlikely a valid timestamp would lose much
+                    // precision.
+                    if (new_flags != old_flags) {
+                        retval = nullptr;
+                    }
+                }
                 if (retval == nullptr) {
                     this->lf_date_time.relock(ls);
+                } else {
+                    log_debug(
+                        "%d: changed time format to '%s' due to %.*s",
+                        line_number,
+                        PTIMEC_FORMAT_STR[this->lf_date_time.dts_fmt_lock],
+                        ts->length(),
+                        ts->data());
                 }
             }
 
diff --git a/src/logfile_sub_source.cc b/src/logfile_sub_source.cc
index d51e87b1..856919a5 100644
--- a/src/logfile_sub_source.cc
+++ b/src/logfile_sub_source.cc
@@ -273,12 +273,13 @@ logfile_sub_source::text_value_for_line(textview_curses& tc,
         value_out = this->lss_token_value;
     }
 
-    if ((this->lss_token_file->is_time_adjusted()
-         || (format->lf_timestamp_flags & ETF_ZONE_SET
-             && format->lf_date_time.dts_zoned_to_local)
-         || format->lf_timestamp_flags & ETF_MACHINE_ORIENTED
-         || !(format->lf_timestamp_flags & ETF_DAY_SET)
-         || !(format->lf_timestamp_flags & ETF_MONTH_SET))
+    if (!this->lss_token_line->is_continued()
+        && (this->lss_token_file->is_time_adjusted()
+            || (format->lf_timestamp_flags & ETF_ZONE_SET
+                && format->lf_date_time.dts_zoned_to_local)
+            || format->lf_timestamp_flags & ETF_MACHINE_ORIENTED
+            || !(format->lf_timestamp_flags & ETF_DAY_SET)
+            || !(format->lf_timestamp_flags & ETF_MONTH_SET))
         && format->lf_date_time.dts_fmt_lock != -1)
     {
         auto time_attr