[gnumeric] csv: be less aggressive in guessing date formats

[Morten Welinder <mortenw src gnome org>]

commit eed9e1436b1ed618cb12e08635dab382014f76d6
Author: Morten Welinder <terra gnome org>
Date:   Sun Jun 9 20:21:54 2019 -0400

    csv: be less aggressive in guessing date formats
    
    Specifically, insist on having all of year, month, and day-of-month.

 NEWS            |  3 +++
 configure.ac    |  2 +-
 src/stf-parse.c | 15 +++++++++++++--
 3 files changed, 17 insertions(+), 3 deletions(-)
---
diff --git a/NEWS b/NEWS
index 9c3a0e4ef..7d3227f97 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,8 @@
 Gnumeric 1.12.46
 
+Morten:
+       * Fix over-eager guessing of dates in csv.  [#401]
+
 --------------------------------------------------------------------------
 Gnumeric 1.12.45
 
diff --git a/configure.ac b/configure.ac
index 5fb52b896..a905c9676 100644
--- a/configure.ac
+++ b/configure.ac
@@ -166,7 +166,7 @@ PKG_PROG_PKG_CONFIG(0.18)
 
 dnl *****************************
 libspreadsheet_reqs="
-       libgoffice-${GOFFICE_API_VER}   >= 0.10.42
+       libgoffice-${GOFFICE_API_VER}   >= 0.10.46
        libgsf-1                >= 1.14.33
        libxml-2.0              >= 2.4.12
 "
diff --git a/src/stf-parse.c b/src/stf-parse.c
index 135de8662..3e0cfa109 100644
--- a/src/stf-parse.c
+++ b/src/stf-parse.c
@@ -1828,8 +1828,9 @@ do_check_date (const char *data, StfGuessFormats flag,
               GODateConventions const *date_conv)
 {
        GnmValue *v;
-       gboolean this_mbd, this_ybm;
+       gboolean has_all, this_mbd, this_ybm;
        int imbd;
+       GOFormat const *fmt;
 
        if (!(*possible & flag))
                return;
@@ -1838,7 +1839,17 @@ do_check_date (const char *data, StfGuessFormats flag,
        if (!v || !VALUE_FMT (v))
                goto fail;
 
-       imbd = go_format_month_before_day (VALUE_FMT (v));
+       fmt = VALUE_FMT (v);
+       has_all = (go_format_has_year (fmt) &&
+                  go_format_has_month (fmt) &&
+                  go_format_has_day (fmt));
+       if (!has_all) {
+               // See #401
+               // Avoid detecting 1.9999 is a date.
+               goto fail;
+       }
+
+       imbd = go_format_month_before_day (fmt);
        this_mbd = (imbd >= 1);
        this_ybm = (imbd == 2);
        if (mbd != this_mbd || ybm != this_ybm)