Fix psql's \dC command to annotate I/O conversion casts as such.

A cast declared WITH INOUT was described as '(binary coercible)',
which seems pretty inaccurate; let's print '(with inout)' instead.
Per complaint from Jean-Pierre Pelletier.

This definitely seems like a bug fix, but given that it's been wrong
since 8.4 and nobody complained before, I'm hesitant to back-patch a
behavior change into stable branches.  It doesn't seem too late for
v11 though.

Discussion: https://postgr.es/m/5b887023.1c69fb81.ff96e.6a1d@mx.google.com

diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 4f7e93fe024cc378685cc0b0293183dab57a520c..4ca0db1d0ca423042cbb60b9256166108b546714 100644 (file)
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -15,6 +15,7 @@
 #include <ctype.h>
 
 #include "catalog/pg_attribute_d.h"
+#include "catalog/pg_cast_d.h"
 #include "catalog/pg_class_d.h"
 #include "catalog/pg_default_acl_d.h"
 #include "fe_utils/string_utils.h"
@@ -3953,37 +3954,56 @@ listCasts(const char *pattern, bool verbose)
 
        initPQExpBuffer(&buf);
 
-       /*
-        * We need a left join to pg_proc for binary casts; the others are just
-        * paranoia.  Also note that we don't attempt to localize '(binary
-        * coercible)', because there's too much risk of gettext translating a
-        * function name that happens to match some string in the PO database.
-        */
        printfPQExpBuffer(&buf,
                                          "SELECT pg_catalog.format_type(castsource, NULL) AS \"%s\",\n"
-                                         "       pg_catalog.format_type(casttarget, NULL) AS \"%s\",\n"
-                                         "       CASE WHEN castfunc = 0 THEN '(binary coercible)'\n"
-                                         "            ELSE p.proname\n"
-                                         "       END as \"%s\",\n"
-                                         "       CASE WHEN c.castcontext = 'e' THEN '%s'\n"
-                                         "            WHEN c.castcontext = 'a' THEN '%s'\n"
-                                         "            ELSE '%s'\n"
-                                         "       END as \"%s\"",
+                                         "       pg_catalog.format_type(casttarget, NULL) AS \"%s\",\n",
                                          gettext_noop("Source type"),
-                                         gettext_noop("Target type"),
-                                         gettext_noop("Function"),
+                                         gettext_noop("Target type"));
+
+       /*
+        * We don't attempt to localize '(binary coercible)' or '(with inout)',
+        * because there's too much risk of gettext translating a function name
+        * that happens to match some string in the PO database.
+        */
+       if (pset.sversion >= 80400)
+               appendPQExpBuffer(&buf,
+                                                 "       CASE WHEN c.castmethod = '%c' THEN '(binary coercible)'\n"
+                                                 "            WHEN c.castmethod = '%c' THEN '(with inout)'\n"
+                                                 "            ELSE p.proname\n"
+                                                 "       END AS \"%s\",\n",
+                                                 COERCION_METHOD_BINARY,
+                                                 COERCION_METHOD_INOUT,
+                                                 gettext_noop("Function"));
+       else
+               appendPQExpBuffer(&buf,
+                                                 "       CASE WHEN c.castfunc = 0 THEN '(binary coercible)'\n"
+                                                 "            ELSE p.proname\n"
+                                                 "       END AS \"%s\",\n",
+                                                 gettext_noop("Function"));
+
+       appendPQExpBuffer(&buf,
+                                         "       CASE WHEN c.castcontext = '%c' THEN '%s'\n"
+                                         "            WHEN c.castcontext = '%c' THEN '%s'\n"
+                                         "            ELSE '%s'\n"
+                                         "       END AS \"%s\"",
+                                         COERCION_CODE_EXPLICIT,
                                          gettext_noop("no"),
+                                         COERCION_CODE_ASSIGNMENT,
                                          gettext_noop("in assignment"),
                                          gettext_noop("yes"),
                                          gettext_noop("Implicit?"));
 
        if (verbose)
                appendPQExpBuffer(&buf,
-                                                 ",\n       d.description AS \"%s\"\n",
+                                                 ",\n       d.description AS \"%s\"",
                                                  gettext_noop("Description"));
 
+       /*
+        * We need a left join to pg_proc for binary casts; the others are just
+        * paranoia.
+        */
        appendPQExpBufferStr(&buf,
-                                                "FROM pg_catalog.pg_cast c LEFT JOIN pg_catalog.pg_proc p\n"
+                                                "\nFROM pg_catalog.pg_cast c LEFT JOIN pg_catalog.pg_proc p\n"
                                                 "     ON c.castfunc = p.oid\n"
                                                 "     LEFT JOIN pg_catalog.pg_type ts\n"
                                                 "     ON c.castsource = ts.oid\n"