Merge remote-tracking branch 'lp-zimoch/dbChannelForDBLinks' into 7.0

* lp-zimoch/dbChannelForDBLinks: (43 commits)
  add tests for empty array filter results
  Fix linkFilterTest, move Release Notes to the right place
  do not handle empty arrays (undefined behavior)
  Revert "new error code for empty arrays"
  test code beautification
  make db_init_event_freelists private
  remove unnecessary check
  remove needless pointer access
  new error code for empty arrays
  clean up code structure
  Release notes updated
  set number of planned link filter tests
  removed unnecessary recGblSetSevr call
  re-order link filter tests to alternate between success and failure
  unused variable removed
  Revert "fix crash in PINI: use local db_field_log"
  initialize free lists when starting dbChannel
  db link filter tests added
  bugfix: dbGet should not crash because of empty array requests
  fix crash in PINI: use local db_field_log
  ...

# Conflicts:
#	documentation/RELEASE_NOTES.md

modules/database/src/std/dev/devAaiSoft.c

@@ -61,9 +61,10 @@ static long init_record(dbCommon *pcommon)
         }
 
         status = dbLoadLinkArray(plink, prec->ftvl, prec->bptr, &nRequest);
-        if (!status && nRequest > 0) {
+        if (!status) {
             prec->nord = nRequest;
             prec->udf = FALSE;
+            return status;
         }
     }
     return 0;
@@ -75,7 +76,7 @@ static long readLocked(struct link *pinp, void *dummy)
     long nRequest = prec->nelm;
     long status = dbGetLink(pinp, prec->ftvl, prec->bptr, 0, &nRequest);
 
-    if (!status && nRequest > 0) {
+    if (!status) {
         prec->nord = nRequest;
         prec->udf = FALSE;
 
@@ -90,8 +91,12 @@ static long read_aai(aaiRecord *prec)
 {
     epicsUInt32 nord = prec->nord;
     struct link *pinp = prec->simm == menuYesNoYES ? &prec->siol : &prec->inp;
-    long status = dbLinkDoLocked(pinp, readLocked, NULL);
+    long status;
 
+    if (dbLinkIsConstant(pinp))
+        return 0;
+
+    status = dbLinkDoLocked(pinp, readLocked, NULL);
     if (status == S_db_noLSET)
         status = readLocked(pinp, NULL);
 

modules/database/src/std/dev/devAiSoft.c

@@ -86,9 +86,10 @@ static long read_ai(aiRecord *prec)
 
         prec->udf = FALSE;
         prec->dpvt = &devAiSoft;        /* Any non-zero value */
+        return 2;
     }
     else
         prec->dpvt = NULL;
 
-    return 2;
+    return status;
 }

modules/database/src/std/dev/devSASoft.c

@@ -66,7 +66,7 @@ static long init_record(dbCommon *pcommon)
 
     status = dbLoadLinkArray(&prec->inp, prec->ftvl, prec->bptr, &nRequest);
 
-    if (!status && nRequest > 0)
+    if (!status)
         subset(prec, nRequest);
 
     return status;
@@ -116,7 +116,7 @@ static long read_sa(subArrayRecord *prec)
             status = readLocked(&prec->inp, &rt);
     }
 
-    if (!status && rt.nRequest > 0) {
+    if (!status) {
         subset(prec, rt.nRequest);
 
         if (nord != prec->nord)

modules/database/src/std/dev/devWfSoft.c

@@ -42,7 +42,7 @@ static long init_record(dbCommon *pcommon)
     long nelm = prec->nelm;
     long status = dbLoadLinkArray(&prec->inp, prec->ftvl, prec->bptr, &nelm);
 
-    if (!status && nelm > 0) {
+    if (!status) {
         prec->nord = nelm;
         prec->udf = FALSE;
     }
@@ -78,11 +78,14 @@ static long read_wf(waveformRecord *prec)
     rt.ptime = (dbLinkIsConstant(&prec->tsel) &&
         prec->tse == epicsTimeEventDeviceTime) ? &prec->time : NULL;
 
+    if (dbLinkIsConstant(&prec->inp))
+        return 0;
+
     status = dbLinkDoLocked(&prec->inp, readLocked, &rt);
     if (status == S_db_noLSET)
         status = readLocked(&prec->inp, &rt);
 
-    if (!status && rt.nRequest > 0) {
+    if (!status) {
         prec->nord = rt.nRequest;
         prec->udf = FALSE;
         if (nord != prec->nord)

modules/database/src/std/rec/aSubRecord.c

@@ -278,10 +278,9 @@ static long fetch_values(aSubRecord *prec)
         long nRequest = (&prec->noa)[i];
         status = dbGetLink(&(&prec->inpa)[i], (&prec->fta)[i], (&prec->a)[i], 0,
             &nRequest);
-        if (nRequest > 0)
-            (&prec->nea)[i] = nRequest;
         if (status)
             return status;
+        (&prec->nea)[i] = nRequest;
     }
     return 0;
 }