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"