From 7b3128b3e4b496f332b4845ecc037c790460e62f Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@ucar.edu>
Date: Wed, 6 Apr 2022 15:54:19 -0600
Subject: [PATCH 1/7] update file permission

---
 nczarr_test/ref_jsonconvention.cdl | 13 +++++++++++++
 nczarr_test/run_jsonconvention.sh  | 31 ++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 nczarr_test/ref_jsonconvention.cdl
 create mode 100755 nczarr_test/run_jsonconvention.sh

diff --git a/nczarr_test/ref_jsonconvention.cdl b/nczarr_test/ref_jsonconvention.cdl
new file mode 100644
index 0000000000..c4a52b8104
--- /dev/null
+++ b/nczarr_test/ref_jsonconvention.cdl
@@ -0,0 +1,13 @@
+netcdf tmp_jsonconvention {
+dimensions:
+	d1 = 1 ;
+variables:
+	int v(d1) ;
+		v:varconvention = "{\n\"key1\": [1,2,3], \"key2\": {\"key3\": \"abc\"}}" ;
+
+// global attributes:
+		:grpconvention = "{\"key1\": [1,2,3], \n\"key2\": {\"key3\": \"abc\"}}" ;
+data:
+
+ v = _ ;
+}
diff --git a/nczarr_test/run_jsonconvention.sh b/nczarr_test/run_jsonconvention.sh
new file mode 100755
index 0000000000..5d96052f1e
--- /dev/null
+++ b/nczarr_test/run_jsonconvention.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+if test "x$srcdir" = x ; then srcdir=`pwd`; fi 
+. ../test_common.sh
+
+. "$srcdir/test_nczarr.sh"
+
+# This shell script tests support for:
+# read/write using json convention
+
+set -e
+
+testcase() {
+zext=$1
+
+echo "*** Test: write then read using json convention"
+fileargs tmp_jsonconvention "mode=nczarr,$zext"
+deletemap $zext $file
+${NCGEN} -4 -b -o "$fileurl" $srcdir/ref_jsonconvention.cdl
+${NCDUMP} $fileurl > tmp_jsonconvention_${zext}.cdl
+# remove '\n' from ref file before comparing
+rm -f tmp_jsonconvention.cdl
+sed -e 's|\\n||g' < ref_jsonconvention.cdl > tmp_jsonconvention.cdl
+diff -b ${srcdir}/tmp_jsonconvention.cdl tmp_jsonconvention_${zext}.cdl
+}
+
+testcase file
+#if test "x$FEATURE_NCZARR_ZIP" = xyes ; then testcase zip; fi
+#if test "x$FEATURE_S3TESTS" = xyes ; then testcase s3; fi
+
+exit 0

From 90fe06592ec3a71e2fa72e318e85e66fd9b27b77 Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@ucar.edu>
Date: Wed, 6 Apr 2022 15:54:42 -0600
Subject: [PATCH 2/7] ckp

---
 include/ncjson.h      |   5 +-
 libdispatch/ncjson.c  |  43 ++++++++++++----
 libnczarr/zsync.c     | 114 ++++++++++++++++++++++++++----------------
 nczarr_test/zisjson.c | 109 ++++++++++++++++++++++++++++++++++++----
 4 files changed, 208 insertions(+), 63 deletions(-)

diff --git a/include/ncjson.h b/include/ncjson.h
index 86a91ef172..c065bc2ed1 100644
--- a/include/ncjson.h
+++ b/include/ncjson.h
@@ -56,9 +56,12 @@ struct NCJconst {int bval; long long ival; double dval; char* sval;};
 extern "C" {
 #endif
 
-/* Parse a JSON string */
+/* Parse a string to NCjson*/
 DLLEXPORT int NCJparse(const char* text, unsigned flags, NCjson** jsonp);
 
+/* Parse a counted string to NCjson*/
+DLLEXPORT int NCJparsen(size_t len, const char* text, unsigned flags, NCjson** jsonp);
+
 /* Reclaim a JSON tree */
 DLLEXPORT extern void NCJreclaim(NCjson* json);
 
diff --git a/libdispatch/ncjson.c b/libdispatch/ncjson.c
index e862175648..c0f85dd3f4 100644
--- a/libdispatch/ncjson.c
+++ b/libdispatch/ncjson.c
@@ -94,6 +94,7 @@ static int NCJyytext(NCJparser*, char* start, size_t pdlen);
 static void NCJreclaimArray(struct NCjlist*);
 static void NCJreclaimDict(struct NCjlist*);
 static int NCJunescape(NCJparser* parser);
+static int unescape1(int c);
 static int listappend(struct NCjlist* list, NCjson* element);
 
 #ifndef NETCDF_JSON_H
@@ -109,24 +110,28 @@ static int bytesappendc(NCJbuf* bufp, const char c);
 
 int
 NCJparse(const char* text, unsigned flags, NCjson** jsonp)
+{
+    return NCJparsen(strlen(text),text,flags,jsonp);
+}
+
+int
+NCJparsen(size_t len, const char* text, unsigned flags, NCjson** jsonp)
 {
     int stat = NCJ_OK;
-    size_t len;
     NCJparser* parser = NULL;
     NCjson* json = NULL;
 
     /* Need at least 1 character of input */
-    if(text == NULL || text[0] == '\0')
+    if(len == 0 || text == NULL)
 	{stat = NCJTHROW(NCJ_ERR); goto done;}
     if(jsonp == NULL) goto done;
     parser = calloc(1,sizeof(NCJparser));
     if(parser == NULL)
 	{stat = NCJTHROW(NCJ_ERR); goto done;}
-    len = strlen(text);
     parser->text = (char*)malloc(len+1+1);
     if(parser->text == NULL)
 	{stat = NCJTHROW(NCJ_ERR); goto done;}
-    strcpy(parser->text,text);
+    memcpy(parser->text,text,len);
     parser->text[len] = '\0';
     parser->text[len+1] = '\0';
     parser->pos = &parser->text[0];
@@ -334,16 +339,21 @@ NCJlex(NCJparser* parser)
 	c = *parser->pos;
 	if(c == '\0') {
 	    token = NCJ_EOF;
-	} else if(c <= ' ' || c == '\177') {
+	} else if(c <= ' ' || c == '\177') {/* ignore whitespace */
+	    parser->pos++;
+	    continue;
+	} else if(c == NCJ_ESCAPE) {
 	    parser->pos++;
-	    continue; /* ignore whitespace */
+	    c = *parser->pos;
+	    *parser->pos = unescape1(c);
+	    continue;
 	} else if(strchr(JSON_WORD, c) != NULL) {
 	    start = parser->pos;
 	    for(;;) {
 		c = *parser->pos++;
 		if(c == '\0' || strchr(JSON_WORD,c) == NULL) break; /* end of word */
 	    }
-	    /* Pushback c if not whitespace */
+	    /* Pushback c */
 	    parser->pos--;
 	    count = ((parser->pos) - start);
 	    if(NCJyytext(parser,start,count)) goto done;
@@ -604,6 +614,21 @@ NCJunescape(NCJparser* parser)
     return NCJTHROW(NCJ_OK);    
 }
 
+/* Unescape a single character */
+static int
+unescape1(int c)
+{
+    switch (c) {
+    case 'b': c = '\b'; break;
+    case 'f': c = '\f'; break;
+    case 'n': c = '\n'; break;
+    case 'r': c = '\r'; break;
+    case 't': c = '\t'; break;
+    default: c = c; break;/* technically not Json conformant */
+    }
+    return c;
+}
+
 #ifdef NCJDEBUG
 static char*
 tokenname(int token)
@@ -896,7 +921,7 @@ NCJunparseR(const NCjson* json, NCJbuf* buf, unsigned flags)
 	if(json->list.len > 0 && json->list.contents != NULL) {
 	    int shortlist = 0;
 	    for(i=0;!shortlist && i < json->list.len;i+=2) {
-		if(i > 0) bytesappendc(buf,NCJ_COMMA);
+		if(i > 0) {bytesappendc(buf,NCJ_COMMA);bytesappendc(buf,' ');};
 		NCJunparseR(json->list.contents[i],buf,flags); /* key */
 		bytesappendc(buf,NCJ_COLON);
 		bytesappendc(buf,' ');
@@ -945,7 +970,7 @@ escape(const char* text, NCJbuf* buf)
 	case '\n': replace = 'n'; break;
 	case '\r': replace = 'r'; break;
 	case '\t': replace = 't'; break;
-	case NCJ_QUOTE: replace = '\''; break;
+	case NCJ_QUOTE: replace = '\"'; break;
 	case NCJ_ESCAPE: replace = '\\'; break;
 	default: break;
 	}
diff --git a/libnczarr/zsync.c b/libnczarr/zsync.c
index 7711032499..aa564211e9 100644
--- a/libnczarr/zsync.c
+++ b/libnczarr/zsync.c
@@ -12,6 +12,10 @@
 
 #undef FILLONCLOSE
 
+/*mnemonics*/
+#define DICTOPEN '{'
+#define DICTCLOSE '}'
+
 /* Forward */
 static int ncz_collect_dims(NC_FILE_INFO_T* file, NC_GRP_INFO_T* grp, NCjson** jdimsp);
 static int ncz_sync_var(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int isclose);
@@ -37,6 +41,8 @@ static int computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, s
 static int inferattrtype(NCjson* values, nc_type* typeidp);
 static int mininttype(unsigned long long u64, int negative);
 static int computedimrefs(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int purezarr, int xarray, int ndims, NClist* dimnames, size64_t* shapes, NC_DIM_INFO_T** dims);
+static int read_dict(NCjson** valuep);
+static int write_dict(size_t len, const void* data, NCjson** jsonp);
 
 /**************************************************/
 /**************************************************/
@@ -776,6 +782,7 @@ ncz_sync_atts(NC_FILE_INFO_T* file, NC_OBJ* container, NCindex* attlist, int isc
 Note that this does not push to the file.
 Also note that attributes of length 1 are stored as singletons, not arrays.
 This is to be more consistent with pure zarr.
+Also implements the JSON dictionary convention.
 @param attlist - [in] the attributes to dictify
 @param jattrsp - [out] the json'ized att list
 @return NC_NOERR
@@ -785,7 +792,7 @@ static int
 ncz_jsonize_atts(NCindex* attlist, NCjson** jattrsp)
 {
     int stat = NC_NOERR;
-    int i;
+    int i, isdict;
     NCjson* jattrs = NULL;
     NCjson* akey = NULL;
     NCjson* jdata = NULL;
@@ -795,9 +802,18 @@ ncz_jsonize_atts(NCindex* attlist, NCjson** jattrsp)
     /* Iterate over the attribute list */
     for(i=0;i<ncindexsize(attlist);i++) {
 	NC_ATT_INFO_T* att = (NC_ATT_INFO_T*)ncindexith(attlist,i);
+	isdict = 0;
 	/* Create the attribute dict value*/
-	if((stat = NCZ_stringconvert(att->nc_typeid,att->len,att->data,&jdata)))
-	    goto done;
+	if(att->nc_typeid == NC_CHAR
+	   && ((char*)att->data)[0] == DICTOPEN
+   	   && ((char*)att->data)[att->len-1] == DICTCLOSE) {
+	    /* this is subject to the JSON dictionary convention? */
+	    if(write_dict(att->len,att->data,&jdata)==NC_NOERR) isdict=1;
+	}
+	if(!isdict) {
+	    if((stat = NCZ_stringconvert(att->nc_typeid,att->len,att->data,&jdata)))
+	        goto done;
+	}
 	if((stat = NCJinsert(jattrs,att->hdr.name,jdata))) goto done;
 	jdata = NULL;
     }
@@ -1011,12 +1027,18 @@ computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, size_t* lenp
     if(typeid == NC_NAT) if((stat = inferattrtype(values,&typeid))) goto done;
     if(typeid == NC_NAT) {stat = NC_EBADTYPE; goto done;}
 
+    if((stat = NC4_inq_atomic_type(typeid, NULL, &typelen)))
+        goto done;
+
     /* Collect the length of the attribute; might be a singleton  */
     switch (NCJsort(values)) {
-    case NCJ_DICT: stat = NC_ENCZARR; goto done;
     case NCJ_ARRAY:
 	count = NCJlength(values);
 	break;
+    case NCJ_DICT:
+	/* Apply the JSON dictionary convention and convert to string */
+	if((stat = read_dict(&values))) goto done;
+	/* fall thru */
     case NCJ_STRING: /* requires special handling as an array of characters; also look out for empty string */
 	if(typeid == NC_CHAR) {
 	    count = strlen(NCJstring(values));
@@ -1029,10 +1051,8 @@ computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, size_t* lenp
 	break;
     }
 
-    if(count > 0) {
+    if(count > 0 && data == NULL) {
         /* Allocate data space */
-        if((stat = NC4_inq_atomic_type(typeid, NULL, &typelen)))
-	    goto done;
         if(typeid == NC_CHAR)
             data = malloc(typelen*(count+1));
         else
@@ -1079,7 +1099,9 @@ inferattrtype(NCjson* value, nc_type* typeidp)
     case NCJ_NULL:
         typeid = NC_CHAR;
 	return NC_NOERR;
-    case NCJ_DICT: /* fall thru */
+    case NCJ_DICT:
+    	typeid = NC_CHAR;
+	goto done;
     case NCJ_UNDEF:
 	return NC_EINVAL;
     default: /* atomic */
@@ -2289,42 +2311,48 @@ computedimrefs(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int purezarr, int xarra
     return THROW(stat);
 }
 
-#if 0
-Not currently used
-Special compatibility case:
-       if the value of the attribute is a dictionary,
-       or an array with non-atomic values, then
-       then stringify it and pretend it is of char type.
-/* Return 1 if this json is not an
-atomic value or an array of atomic values.
-That is, it does not look like valid
-attribute data.
+/**
+Implement the JSON convention for dictionaries.
+
+Reading: If the value of the attribute is a dictionary, then stringify
+         it as the value and make the attribute be of type "char".
+
+Writing: if the attribute is of type char and looks like a JSON dictionary,
+	 then parse it as JSON and use that as its value in .zattrs.
 */
+
 static int
-iscomplexjson(NCjson* j)
+read_dict(NCjson** jvaluep)
 {
-    int i;
-    switch(NCJsort(j)) {
-    case NCJ_ARRAY:
-	/* verify that the elements of the array are not complex */
-	for(i=0;i<NCJlength(j);i++) {
-	    switch (NCJith(j,NCJsort(i)))) {
-	    case NCJ_DICT:
-    	    case NCJ_ARRAY:
-	    case NCJ_UNDEF:
-	    case NCJ_NULL:
-		return 1;
-	    default: break;
-	    }
-	}
-	return 0;
-    case NCJ_DICT:
-    case NCJ_UNDEF:
-    case NCJ_NULL:
-	break;
-    default:
-        return 0;
-    }
-    return 1;
+    int stat = NC_NOERR;
+    NCjson* jdict = NULL;
+    NCjson* jtext = NULL;
+    char* text = NULL;
+
+    assert(jvaluep != NULL && *jvaluep != NULL);
+    jdict = *jvaluep;
+    if(NCJsort(jdict) != NCJ_DICT)  {stat = NC_EINVAL; goto done;}
+    if(NCJunparse(jdict,0,&text)) {stat = NC_EINVAL; goto done;}
+    if(NCJnewstring(NCJ_STRING,text,&jtext)) {stat = NC_EINVAL; goto done;}
+    *jvaluep = jtext;
+done:
+    nullfree(text);
+    return stat;
 }
-#endif
+
+static int
+write_dict(size_t len, const void* data, NCjson** jsonp)
+{
+    int stat = NC_NOERR;
+    NCjson* jdict = NULL;
+
+    assert(jsonp != NULL);
+    if(NCJparsen(len,(char*)data,0,&jdict))
+        {stat = NC_EINVAL; goto done;}
+    if(NCJsort(jdict) != NCJ_DICT)
+        {stat = NC_EINVAL; goto done;}
+    *jsonp = jdict;
+done:
+    return stat;
+}
+
diff --git a/nczarr_test/zisjson.c b/nczarr_test/zisjson.c
index 186ae45f6c..e13c69f23f 100644
--- a/nczarr_test/zisjson.c
+++ b/nczarr_test/zisjson.c
@@ -7,36 +7,122 @@
    Output 1 or 0.
 */
 
-#include "config.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
 
 #include "stdlib.h"
 #include "stdio.h"
+#include "string.h"
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 
+#if defined(_WIN32) && !defined(__MINGW32__)
+#include "XGetopt.h"
+#else
+#include <getopt.h>
+#endif
+
 #include "netcdf.h"
 #include "nclist.h"
 #include "ncjson.h"
 
 #define MAXREAD 8192
 
+/* Command line options */
+struct Jsonpptions {
+    int trace;
+} jsonoptions;
+
+static const char*
+sortname(int thesort)
+{
+    switch(thesort) {
+    default: break;
+    case NCJ_INT: return "NCJ_INT";
+    case NCJ_DOUBLE: return "NCJ_DOUBLE";
+    case NCJ_BOOLEAN: return "NCJ_BOOLEAN";
+    case NCJ_STRING: return "NCJ_STRING";
+    case NCJ_DICT: return "NCJ_DICT";
+    case NCJ_ARRAY: return "NCJ_ARRAY";
+    case NCJ_NULL: return "NCJ_NULL";
+    }
+    return "?";
+}
+
+
+static void
+jsontrace(NCjson* json, int depth)
+{
+    int i;
+    if(json == NULL) goto done;
+    printf("[%d] sort=%s",depth,sortname(NCJsort(json)));
+    switch(NCJsort(json)) {
+    case NCJ_INT:
+    case NCJ_DOUBLE:
+    case NCJ_BOOLEAN:
+    case NCJ_STRING:
+	printf(" string=|%s|\n",NCJstring(json));
+	break;
+    case NCJ_NULL:
+	printf("\n");
+	break;
+    case NCJ_ARRAY:
+	printf("\n");
+	for(i=0;i<NCJlength(json);i++)
+	    jsontrace(NCJith(json,i),depth+1);
+	break;
+    case NCJ_DICT:
+	printf("\n");
+	for(i=0;i<NCJlength(json);i+=2) {
+	    jsontrace(NCJith(json,i),depth+1);
+	    jsontrace(NCJith(json,i+1),depth+1);
+	} break;
+    default: break;
+    }
+done:
+    return;
+}
+
 int
 main(int argc, char** argv)
 {
     int stat = NC_NOERR;
     char text[MAXREAD+1];
     NCjson* json = NULL;
-    int i, red;
+    int i, red, c;
     FILE* f = NULL;
 
-    if(argc > 1) {
-	/* use argv[1] as input */
-	f = fopen(argv[1],"r");
-	if(f == NULL) {fprintf(stderr,"No such file: %s\n",argv[1]); exit(1);}
-    } else
-        f = stdin;
+    nc_initialize();
+    memset((void*)&jsonoptions,0,sizeof(jsonoptions));
+
+    while ((c = getopt(argc, argv, "t")) != EOF) {
+	switch(c) {
+	case 't': jsonoptions.trace = 1; break;
+	case '?':
+	   fprintf(stderr,"unknown option\n");
+	   exit(1);
+	}
+    }	
+
+    /* get file argument */
+    argc -= optind;
+    argv += optind;
+
+    if (argc > 1) {
+	fprintf(stderr, "zisjson: only one input file argument permitted\n");
+	exit(1);
+    }
+    if (argc == 0)
+	f = stdin;
+    else {
+        /* use argv[0] as input */
+        f = fopen(argv[0],"r");
+        if(f == NULL) {fprintf(stderr,"No such file: %s\n",argv[1]); exit(1);}
+    }
 
     /* Read json from stdin */
     for(i=0;;i++) {
@@ -54,9 +140,12 @@ main(int argc, char** argv)
 	stat = NC_EEMPTY;
     } else {
         stat = NCJparse(text,0,&json);
-	NCJreclaim(json);
+	if(!stat) {
+	    if(jsonoptions.trace) jsontrace(json,0);
+	    NCJreclaim(json);
+	}
     }
-    printf("%d",(stat==NC_NOERR?1:0)); /* parse success|failure */    
+    printf("%d",(stat?0:1)); /* parse success|failure */    
     if(f != stdin) fclose(f);
     return 0;
 }

From d5798aff2eef6e83ab5cf2e36e854f6119df117b Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@ucar.edu>
Date: Wed, 6 Apr 2022 15:57:17 -0600
Subject: [PATCH 3/7] testing

---
 .github/workflows/run_tests_ubuntu.yml    | 2 +-
 .github/workflows/run_tests_win_mingw.yml | 2 +-
 nczarr_test/Makefile.am                   | 5 +++--
 nczarr_test/run_jsonconvention.sh         | 4 ++--
 4 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/run_tests_ubuntu.yml b/.github/workflows/run_tests_ubuntu.yml
index 93f402c150..15cbf017f6 100644
--- a/.github/workflows/run_tests_ubuntu.yml
+++ b/.github/workflows/run_tests_ubuntu.yml
@@ -4,7 +4,7 @@
 
 name: Run Ubuntu/Linux netCDF Tests
 
-on: [ pull_request ]
+on: [pull_request,push]
 
 jobs:
 
diff --git a/.github/workflows/run_tests_win_mingw.yml b/.github/workflows/run_tests_win_mingw.yml
index 913920a3aa..aaf999e6a4 100644
--- a/.github/workflows/run_tests_win_mingw.yml
+++ b/.github/workflows/run_tests_win_mingw.yml
@@ -7,7 +7,7 @@
 name: Run MSYS2, MinGW64-based Tests
 
 
-on: [pull_request]
+on: [pull_request,push]
 
 jobs:
 
diff --git a/nczarr_test/Makefile.am b/nczarr_test/Makefile.am
index e9efa73f7e..968b5a821e 100644
--- a/nczarr_test/Makefile.am
+++ b/nczarr_test/Makefile.am
@@ -61,6 +61,7 @@ TESTS += run_purezarr.sh
 TESTS += run_interop.sh
 TESTS += run_misc.sh
 TESTS += run_nczarr_fill.sh
+TESTS += run_jsonconvention.sh
 
 endif
 
@@ -127,7 +128,7 @@ run_ut_map.sh run_ut_mapapi.sh run_ut_misc.sh run_ut_chunk.sh run_ncgen4.sh \
 run_nccopyz.sh run_fillonlyz.sh run_chunkcases.sh test_nczarr.sh run_perf_chunks1.sh run_s3_cleanup.sh \
 run_purezarr.sh run_interop.sh run_misc.sh \
 run_filter.sh run_specific_filters.sh \
-run_newformat.sh run_nczarr_fill.sh run_quantize.sh
+run_newformat.sh run_nczarr_fill.sh run_quantize.sh run_jsonconvention.sh
 
 EXTRA_DIST += \
 ref_ut_map_create.cdl ref_ut_map_writedata.cdl ref_ut_map_writemeta2.cdl ref_ut_map_writemeta.cdl \
@@ -147,7 +148,7 @@ ref_bzip2.cdl ref_filtered.cdl ref_multi.cdl \
 ref_any.cdl ref_oldformat.cdl ref_oldformat.zip ref_newformatpure.cdl \
 ref_quotes.zip ref_quotes.cdl \
 ref_groups.h5 ref_byte.zarr.zip ref_byte_fill_value_null.zarr.zip \
-ref_groups_regular.cdl ref_byte.cdl ref_byte_fill_value_null.cdl
+ref_groups_regular.cdl ref_byte.cdl ref_byte_fill_value_null.cdl ref_jsonconvention.cdl
 
 # Interoperability files
 EXTRA_DIST += ref_power_901_constants.zip ref_power_901_constants.cdl ref_quotes.zip ref_quotes.cdl 
diff --git a/nczarr_test/run_jsonconvention.sh b/nczarr_test/run_jsonconvention.sh
index 5d96052f1e..fc9c84d1dc 100755
--- a/nczarr_test/run_jsonconvention.sh
+++ b/nczarr_test/run_jsonconvention.sh
@@ -25,7 +25,7 @@ diff -b ${srcdir}/tmp_jsonconvention.cdl tmp_jsonconvention_${zext}.cdl
 }
 
 testcase file
-#if test "x$FEATURE_NCZARR_ZIP" = xyes ; then testcase zip; fi
-#if test "x$FEATURE_S3TESTS" = xyes ; then testcase s3; fi
+if test "x$FEATURE_NCZARR_ZIP" = xyes ; then testcase zip; fi
+if test "x$FEATURE_S3TESTS" = xyes ; then testcase s3; fi
 
 exit 0

From 56167a777541f8aa73513163cc7d80cef222fa6b Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@ucar.edu>
Date: Wed, 6 Apr 2022 17:16:40 -0600
Subject: [PATCH 4/7] final

---
 nc_test4/tst_broken_files.c       | 3 ++-
 nczarr_test/CMakeLists.txt        | 3 ++-
 nczarr_test/run_jsonconvention.sh | 4 ++--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/nc_test4/tst_broken_files.c b/nc_test4/tst_broken_files.c
index af68b26905..22bf3e8802 100644
--- a/nc_test4/tst_broken_files.c
+++ b/nc_test4/tst_broken_files.c
@@ -28,7 +28,8 @@ main() {
         fclose(fp);
 
         int  ncid;
-        if (nc_open(FILE_NAME, 0, &ncid) != NC_EHDFERR) ERR;
+        int stat=nc_open(FILE_NAME, 0, &ncid);
+        if (stat != NC_EHDFERR && stat != NC_ENOTNC) ERR;
     }
 
     {
diff --git a/nczarr_test/CMakeLists.txt b/nczarr_test/CMakeLists.txt
index 03db4557fb..ef31d15df1 100644
--- a/nczarr_test/CMakeLists.txt
+++ b/nczarr_test/CMakeLists.txt
@@ -73,7 +73,7 @@ IF(ENABLE_TESTS)
   BUILD_BIN_TEST(zmapio ${COMMONSRC})
   TARGET_INCLUDE_DIRECTORIES(zmapio PUBLIC ../libnczarr)
   BUILD_BIN_TEST(zhex)
-  BUILD_BIN_TEST(zisjson)
+  BUILD_BIN_TEST(zisjson ${COMMONSRC})
   TARGET_INCLUDE_DIRECTORIES(zisjson PUBLIC ../libnczarr)
   BUILD_BIN_TEST(zs3parse ${COMMONSRC})
   TARGET_INCLUDE_DIRECTORIES(zs3parse PUBLIC ../libnczarr)
@@ -108,6 +108,7 @@ IF(ENABLE_TESTS)
     add_sh_test(nczarr_test run_interop)
     add_sh_test(nczarr_test run_misc)
     add_sh_test(nczarr_test run_nczarr_fill)
+    add_sh_test(nczarr_test run_jsonconvention)
 
     BUILD_BIN_TEST(test_quantize ${TSTCOMMONSRC})
     add_sh_test(nczarr_test run_quantize)
diff --git a/nczarr_test/run_jsonconvention.sh b/nczarr_test/run_jsonconvention.sh
index fc9c84d1dc..7cf786a685 100755
--- a/nczarr_test/run_jsonconvention.sh
+++ b/nczarr_test/run_jsonconvention.sh
@@ -20,8 +20,8 @@ ${NCGEN} -4 -b -o "$fileurl" $srcdir/ref_jsonconvention.cdl
 ${NCDUMP} $fileurl > tmp_jsonconvention_${zext}.cdl
 # remove '\n' from ref file before comparing
 rm -f tmp_jsonconvention.cdl
-sed -e 's|\\n||g' < ref_jsonconvention.cdl > tmp_jsonconvention.cdl
-diff -b ${srcdir}/tmp_jsonconvention.cdl tmp_jsonconvention_${zext}.cdl
+sed -e 's|\\n||g' < ${srcdir}/ref_jsonconvention.cdl > tmp_jsonconvention.cdl
+diff -b tmp_jsonconvention.cdl tmp_jsonconvention_${zext}.cdl
 }
 
 testcase file

From 9f78be8bb8af0cbc2293b2e1cd8984894762cc6b Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@ucar.edu>
Date: Wed, 6 Apr 2022 18:22:59 -0600
Subject: [PATCH 5/7] Allow the read/write of JSON-valued Zarr attributes.

A number of other packages that read/write Zarr insert
attributes whose value is a dictionary containing specialized
information.  An example is the GDAL Driver convention (see
https://gdal.org/drivers/raster/zarr.html).

In order to handle such attributes, this PR enforces a special
convention. It applies to both pure Zarr an NCZarr format as
written by the netdf-c library.

The convention is as follows:

## Reading
Suppose an attribute is read from *.zattrs* and it has a JSON
value that is a a dictionary.  In this case, the JSON dictionary
is converted to a string value.  It then appears in the netcdf-c
API as if it is a character valued attribute of the same name,
and whose value is the "stringified" dictionary.

# Writing
Suppose an attribute is of type character and its *value* *looks like*
a JSON dictionary. In this case, it is parsed to JSON
and written as the value of the attribute in the NCZarr file.
Here the *value* is the concatenation of all the characters
in the attributes netcdf-c value.
The term "looks like" means that the *value*'s first character is
"{", its last value is "}", and it can be successfully parsed
by a JSON parser.

A test case, *nczarr_test/run_jsonconventions.sh* was also added.

## Misc. Unrelated Changes

1. Fix an error in nc_test4/tst_broken_files.c
2. Modify the internal JSON parser API.
3. Modify the nczarr_test/zisjson program is modified to support
   this convention.
---
 .github/workflows/run_tests_osx.yml    |   2 +-
 .github/workflows/run_tests_ubuntu.yml |   2 +-
 include/ncjson.h                       |   5 +-
 libdispatch/ncjson.c                   |  43 ++++++++--
 libnczarr/zsync.c                      | 114 +++++++++++++++----------
 nc_test4/tst_broken_files.c            |   3 +-
 nczarr_test/CMakeLists.txt             |   3 +-
 nczarr_test/Makefile.am                |   5 +-
 nczarr_test/ref_jsonconvention.cdl     |  13 +++
 nczarr_test/run_jsonconvention.sh      |  31 +++++++
 nczarr_test/zisjson.c                  | 109 ++++++++++++++++++++---
 11 files changed, 261 insertions(+), 69 deletions(-)
 create mode 100644 nczarr_test/ref_jsonconvention.cdl
 create mode 100755 nczarr_test/run_jsonconvention.sh

diff --git a/.github/workflows/run_tests_osx.yml b/.github/workflows/run_tests_osx.yml
index aa35ae8795..8e9d65a6fb 100644
--- a/.github/workflows/run_tests_osx.yml
+++ b/.github/workflows/run_tests_osx.yml
@@ -7,7 +7,7 @@
 name: Run macOS-based netCDF Tests
 
 
-on: [pull_request,push]
+on: [pull_request]
 
 jobs:
 
diff --git a/.github/workflows/run_tests_ubuntu.yml b/.github/workflows/run_tests_ubuntu.yml
index a1f6544249..92b5bfca66 100644
--- a/.github/workflows/run_tests_ubuntu.yml
+++ b/.github/workflows/run_tests_ubuntu.yml
@@ -4,7 +4,7 @@
 
 name: Run Ubuntu/Linux netCDF Tests
 
-on: [ pull_request ]
+on: [pull_request]
 
 jobs:
 
diff --git a/include/ncjson.h b/include/ncjson.h
index 86a91ef172..c065bc2ed1 100644
--- a/include/ncjson.h
+++ b/include/ncjson.h
@@ -56,9 +56,12 @@ struct NCJconst {int bval; long long ival; double dval; char* sval;};
 extern "C" {
 #endif
 
-/* Parse a JSON string */
+/* Parse a string to NCjson*/
 DLLEXPORT int NCJparse(const char* text, unsigned flags, NCjson** jsonp);
 
+/* Parse a counted string to NCjson*/
+DLLEXPORT int NCJparsen(size_t len, const char* text, unsigned flags, NCjson** jsonp);
+
 /* Reclaim a JSON tree */
 DLLEXPORT extern void NCJreclaim(NCjson* json);
 
diff --git a/libdispatch/ncjson.c b/libdispatch/ncjson.c
index e862175648..c0f85dd3f4 100644
--- a/libdispatch/ncjson.c
+++ b/libdispatch/ncjson.c
@@ -94,6 +94,7 @@ static int NCJyytext(NCJparser*, char* start, size_t pdlen);
 static void NCJreclaimArray(struct NCjlist*);
 static void NCJreclaimDict(struct NCjlist*);
 static int NCJunescape(NCJparser* parser);
+static int unescape1(int c);
 static int listappend(struct NCjlist* list, NCjson* element);
 
 #ifndef NETCDF_JSON_H
@@ -109,24 +110,28 @@ static int bytesappendc(NCJbuf* bufp, const char c);
 
 int
 NCJparse(const char* text, unsigned flags, NCjson** jsonp)
+{
+    return NCJparsen(strlen(text),text,flags,jsonp);
+}
+
+int
+NCJparsen(size_t len, const char* text, unsigned flags, NCjson** jsonp)
 {
     int stat = NCJ_OK;
-    size_t len;
     NCJparser* parser = NULL;
     NCjson* json = NULL;
 
     /* Need at least 1 character of input */
-    if(text == NULL || text[0] == '\0')
+    if(len == 0 || text == NULL)
 	{stat = NCJTHROW(NCJ_ERR); goto done;}
     if(jsonp == NULL) goto done;
     parser = calloc(1,sizeof(NCJparser));
     if(parser == NULL)
 	{stat = NCJTHROW(NCJ_ERR); goto done;}
-    len = strlen(text);
     parser->text = (char*)malloc(len+1+1);
     if(parser->text == NULL)
 	{stat = NCJTHROW(NCJ_ERR); goto done;}
-    strcpy(parser->text,text);
+    memcpy(parser->text,text,len);
     parser->text[len] = '\0';
     parser->text[len+1] = '\0';
     parser->pos = &parser->text[0];
@@ -334,16 +339,21 @@ NCJlex(NCJparser* parser)
 	c = *parser->pos;
 	if(c == '\0') {
 	    token = NCJ_EOF;
-	} else if(c <= ' ' || c == '\177') {
+	} else if(c <= ' ' || c == '\177') {/* ignore whitespace */
+	    parser->pos++;
+	    continue;
+	} else if(c == NCJ_ESCAPE) {
 	    parser->pos++;
-	    continue; /* ignore whitespace */
+	    c = *parser->pos;
+	    *parser->pos = unescape1(c);
+	    continue;
 	} else if(strchr(JSON_WORD, c) != NULL) {
 	    start = parser->pos;
 	    for(;;) {
 		c = *parser->pos++;
 		if(c == '\0' || strchr(JSON_WORD,c) == NULL) break; /* end of word */
 	    }
-	    /* Pushback c if not whitespace */
+	    /* Pushback c */
 	    parser->pos--;
 	    count = ((parser->pos) - start);
 	    if(NCJyytext(parser,start,count)) goto done;
@@ -604,6 +614,21 @@ NCJunescape(NCJparser* parser)
     return NCJTHROW(NCJ_OK);    
 }
 
+/* Unescape a single character */
+static int
+unescape1(int c)
+{
+    switch (c) {
+    case 'b': c = '\b'; break;
+    case 'f': c = '\f'; break;
+    case 'n': c = '\n'; break;
+    case 'r': c = '\r'; break;
+    case 't': c = '\t'; break;
+    default: c = c; break;/* technically not Json conformant */
+    }
+    return c;
+}
+
 #ifdef NCJDEBUG
 static char*
 tokenname(int token)
@@ -896,7 +921,7 @@ NCJunparseR(const NCjson* json, NCJbuf* buf, unsigned flags)
 	if(json->list.len > 0 && json->list.contents != NULL) {
 	    int shortlist = 0;
 	    for(i=0;!shortlist && i < json->list.len;i+=2) {
-		if(i > 0) bytesappendc(buf,NCJ_COMMA);
+		if(i > 0) {bytesappendc(buf,NCJ_COMMA);bytesappendc(buf,' ');};
 		NCJunparseR(json->list.contents[i],buf,flags); /* key */
 		bytesappendc(buf,NCJ_COLON);
 		bytesappendc(buf,' ');
@@ -945,7 +970,7 @@ escape(const char* text, NCJbuf* buf)
 	case '\n': replace = 'n'; break;
 	case '\r': replace = 'r'; break;
 	case '\t': replace = 't'; break;
-	case NCJ_QUOTE: replace = '\''; break;
+	case NCJ_QUOTE: replace = '\"'; break;
 	case NCJ_ESCAPE: replace = '\\'; break;
 	default: break;
 	}
diff --git a/libnczarr/zsync.c b/libnczarr/zsync.c
index 7711032499..aa564211e9 100644
--- a/libnczarr/zsync.c
+++ b/libnczarr/zsync.c
@@ -12,6 +12,10 @@
 
 #undef FILLONCLOSE
 
+/*mnemonics*/
+#define DICTOPEN '{'
+#define DICTCLOSE '}'
+
 /* Forward */
 static int ncz_collect_dims(NC_FILE_INFO_T* file, NC_GRP_INFO_T* grp, NCjson** jdimsp);
 static int ncz_sync_var(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int isclose);
@@ -37,6 +41,8 @@ static int computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, s
 static int inferattrtype(NCjson* values, nc_type* typeidp);
 static int mininttype(unsigned long long u64, int negative);
 static int computedimrefs(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int purezarr, int xarray, int ndims, NClist* dimnames, size64_t* shapes, NC_DIM_INFO_T** dims);
+static int read_dict(NCjson** valuep);
+static int write_dict(size_t len, const void* data, NCjson** jsonp);
 
 /**************************************************/
 /**************************************************/
@@ -776,6 +782,7 @@ ncz_sync_atts(NC_FILE_INFO_T* file, NC_OBJ* container, NCindex* attlist, int isc
 Note that this does not push to the file.
 Also note that attributes of length 1 are stored as singletons, not arrays.
 This is to be more consistent with pure zarr.
+Also implements the JSON dictionary convention.
 @param attlist - [in] the attributes to dictify
 @param jattrsp - [out] the json'ized att list
 @return NC_NOERR
@@ -785,7 +792,7 @@ static int
 ncz_jsonize_atts(NCindex* attlist, NCjson** jattrsp)
 {
     int stat = NC_NOERR;
-    int i;
+    int i, isdict;
     NCjson* jattrs = NULL;
     NCjson* akey = NULL;
     NCjson* jdata = NULL;
@@ -795,9 +802,18 @@ ncz_jsonize_atts(NCindex* attlist, NCjson** jattrsp)
     /* Iterate over the attribute list */
     for(i=0;i<ncindexsize(attlist);i++) {
 	NC_ATT_INFO_T* att = (NC_ATT_INFO_T*)ncindexith(attlist,i);
+	isdict = 0;
 	/* Create the attribute dict value*/
-	if((stat = NCZ_stringconvert(att->nc_typeid,att->len,att->data,&jdata)))
-	    goto done;
+	if(att->nc_typeid == NC_CHAR
+	   && ((char*)att->data)[0] == DICTOPEN
+   	   && ((char*)att->data)[att->len-1] == DICTCLOSE) {
+	    /* this is subject to the JSON dictionary convention? */
+	    if(write_dict(att->len,att->data,&jdata)==NC_NOERR) isdict=1;
+	}
+	if(!isdict) {
+	    if((stat = NCZ_stringconvert(att->nc_typeid,att->len,att->data,&jdata)))
+	        goto done;
+	}
 	if((stat = NCJinsert(jattrs,att->hdr.name,jdata))) goto done;
 	jdata = NULL;
     }
@@ -1011,12 +1027,18 @@ computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, size_t* lenp
     if(typeid == NC_NAT) if((stat = inferattrtype(values,&typeid))) goto done;
     if(typeid == NC_NAT) {stat = NC_EBADTYPE; goto done;}
 
+    if((stat = NC4_inq_atomic_type(typeid, NULL, &typelen)))
+        goto done;
+
     /* Collect the length of the attribute; might be a singleton  */
     switch (NCJsort(values)) {
-    case NCJ_DICT: stat = NC_ENCZARR; goto done;
     case NCJ_ARRAY:
 	count = NCJlength(values);
 	break;
+    case NCJ_DICT:
+	/* Apply the JSON dictionary convention and convert to string */
+	if((stat = read_dict(&values))) goto done;
+	/* fall thru */
     case NCJ_STRING: /* requires special handling as an array of characters; also look out for empty string */
 	if(typeid == NC_CHAR) {
 	    count = strlen(NCJstring(values));
@@ -1029,10 +1051,8 @@ computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, size_t* lenp
 	break;
     }
 
-    if(count > 0) {
+    if(count > 0 && data == NULL) {
         /* Allocate data space */
-        if((stat = NC4_inq_atomic_type(typeid, NULL, &typelen)))
-	    goto done;
         if(typeid == NC_CHAR)
             data = malloc(typelen*(count+1));
         else
@@ -1079,7 +1099,9 @@ inferattrtype(NCjson* value, nc_type* typeidp)
     case NCJ_NULL:
         typeid = NC_CHAR;
 	return NC_NOERR;
-    case NCJ_DICT: /* fall thru */
+    case NCJ_DICT:
+    	typeid = NC_CHAR;
+	goto done;
     case NCJ_UNDEF:
 	return NC_EINVAL;
     default: /* atomic */
@@ -2289,42 +2311,48 @@ computedimrefs(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int purezarr, int xarra
     return THROW(stat);
 }
 
-#if 0
-Not currently used
-Special compatibility case:
-       if the value of the attribute is a dictionary,
-       or an array with non-atomic values, then
-       then stringify it and pretend it is of char type.
-/* Return 1 if this json is not an
-atomic value or an array of atomic values.
-That is, it does not look like valid
-attribute data.
+/**
+Implement the JSON convention for dictionaries.
+
+Reading: If the value of the attribute is a dictionary, then stringify
+         it as the value and make the attribute be of type "char".
+
+Writing: if the attribute is of type char and looks like a JSON dictionary,
+	 then parse it as JSON and use that as its value in .zattrs.
 */
+
 static int
-iscomplexjson(NCjson* j)
+read_dict(NCjson** jvaluep)
 {
-    int i;
-    switch(NCJsort(j)) {
-    case NCJ_ARRAY:
-	/* verify that the elements of the array are not complex */
-	for(i=0;i<NCJlength(j);i++) {
-	    switch (NCJith(j,NCJsort(i)))) {
-	    case NCJ_DICT:
-    	    case NCJ_ARRAY:
-	    case NCJ_UNDEF:
-	    case NCJ_NULL:
-		return 1;
-	    default: break;
-	    }
-	}
-	return 0;
-    case NCJ_DICT:
-    case NCJ_UNDEF:
-    case NCJ_NULL:
-	break;
-    default:
-        return 0;
-    }
-    return 1;
+    int stat = NC_NOERR;
+    NCjson* jdict = NULL;
+    NCjson* jtext = NULL;
+    char* text = NULL;
+
+    assert(jvaluep != NULL && *jvaluep != NULL);
+    jdict = *jvaluep;
+    if(NCJsort(jdict) != NCJ_DICT)  {stat = NC_EINVAL; goto done;}
+    if(NCJunparse(jdict,0,&text)) {stat = NC_EINVAL; goto done;}
+    if(NCJnewstring(NCJ_STRING,text,&jtext)) {stat = NC_EINVAL; goto done;}
+    *jvaluep = jtext;
+done:
+    nullfree(text);
+    return stat;
 }
-#endif
+
+static int
+write_dict(size_t len, const void* data, NCjson** jsonp)
+{
+    int stat = NC_NOERR;
+    NCjson* jdict = NULL;
+
+    assert(jsonp != NULL);
+    if(NCJparsen(len,(char*)data,0,&jdict))
+        {stat = NC_EINVAL; goto done;}
+    if(NCJsort(jdict) != NCJ_DICT)
+        {stat = NC_EINVAL; goto done;}
+    *jsonp = jdict;
+done:
+    return stat;
+}
+
diff --git a/nc_test4/tst_broken_files.c b/nc_test4/tst_broken_files.c
index af68b26905..22bf3e8802 100644
--- a/nc_test4/tst_broken_files.c
+++ b/nc_test4/tst_broken_files.c
@@ -28,7 +28,8 @@ main() {
         fclose(fp);
 
         int  ncid;
-        if (nc_open(FILE_NAME, 0, &ncid) != NC_EHDFERR) ERR;
+        int stat=nc_open(FILE_NAME, 0, &ncid);
+        if (stat != NC_EHDFERR && stat != NC_ENOTNC) ERR;
     }
 
     {
diff --git a/nczarr_test/CMakeLists.txt b/nczarr_test/CMakeLists.txt
index 03db4557fb..ef31d15df1 100644
--- a/nczarr_test/CMakeLists.txt
+++ b/nczarr_test/CMakeLists.txt
@@ -73,7 +73,7 @@ IF(ENABLE_TESTS)
   BUILD_BIN_TEST(zmapio ${COMMONSRC})
   TARGET_INCLUDE_DIRECTORIES(zmapio PUBLIC ../libnczarr)
   BUILD_BIN_TEST(zhex)
-  BUILD_BIN_TEST(zisjson)
+  BUILD_BIN_TEST(zisjson ${COMMONSRC})
   TARGET_INCLUDE_DIRECTORIES(zisjson PUBLIC ../libnczarr)
   BUILD_BIN_TEST(zs3parse ${COMMONSRC})
   TARGET_INCLUDE_DIRECTORIES(zs3parse PUBLIC ../libnczarr)
@@ -108,6 +108,7 @@ IF(ENABLE_TESTS)
     add_sh_test(nczarr_test run_interop)
     add_sh_test(nczarr_test run_misc)
     add_sh_test(nczarr_test run_nczarr_fill)
+    add_sh_test(nczarr_test run_jsonconvention)
 
     BUILD_BIN_TEST(test_quantize ${TSTCOMMONSRC})
     add_sh_test(nczarr_test run_quantize)
diff --git a/nczarr_test/Makefile.am b/nczarr_test/Makefile.am
index a7ca56d36c..b2241152ea 100644
--- a/nczarr_test/Makefile.am
+++ b/nczarr_test/Makefile.am
@@ -61,6 +61,7 @@ TESTS += run_purezarr.sh
 TESTS += run_interop.sh
 TESTS += run_misc.sh
 TESTS += run_nczarr_fill.sh
+TESTS += run_jsonconvention.sh
 
 endif
 
@@ -127,7 +128,7 @@ run_ut_map.sh run_ut_mapapi.sh run_ut_misc.sh run_ut_chunk.sh run_ncgen4.sh \
 run_nccopyz.sh run_fillonlyz.sh run_chunkcases.sh test_nczarr.sh run_perf_chunks1.sh run_s3_cleanup.sh \
 run_purezarr.sh run_interop.sh run_misc.sh \
 run_filter.sh run_specific_filters.sh \
-run_newformat.sh run_nczarr_fill.sh run_quantize.sh
+run_newformat.sh run_nczarr_fill.sh run_quantize.sh run_jsonconvention.sh
 
 EXTRA_DIST += \
 ref_ut_map_create.cdl ref_ut_map_writedata.cdl ref_ut_map_writemeta2.cdl ref_ut_map_writemeta.cdl \
@@ -147,7 +148,7 @@ ref_bzip2.cdl ref_filtered.cdl ref_multi.cdl \
 ref_any.cdl ref_oldformat.cdl ref_oldformat.zip ref_newformatpure.cdl \
 ref_quotes.zip ref_quotes.cdl \
 ref_groups.h5 ref_byte.zarr.zip ref_byte_fill_value_null.zarr.zip \
-ref_groups_regular.cdl ref_byte.cdl ref_byte_fill_value_null.cdl
+ref_groups_regular.cdl ref_byte.cdl ref_byte_fill_value_null.cdl ref_jsonconvention.cdl
 
 # Interoperability files
 EXTRA_DIST += ref_power_901_constants.zip ref_power_901_constants.cdl ref_quotes.zip ref_quotes.cdl 
diff --git a/nczarr_test/ref_jsonconvention.cdl b/nczarr_test/ref_jsonconvention.cdl
new file mode 100644
index 0000000000..c4a52b8104
--- /dev/null
+++ b/nczarr_test/ref_jsonconvention.cdl
@@ -0,0 +1,13 @@
+netcdf tmp_jsonconvention {
+dimensions:
+	d1 = 1 ;
+variables:
+	int v(d1) ;
+		v:varconvention = "{\n\"key1\": [1,2,3], \"key2\": {\"key3\": \"abc\"}}" ;
+
+// global attributes:
+		:grpconvention = "{\"key1\": [1,2,3], \n\"key2\": {\"key3\": \"abc\"}}" ;
+data:
+
+ v = _ ;
+}
diff --git a/nczarr_test/run_jsonconvention.sh b/nczarr_test/run_jsonconvention.sh
new file mode 100755
index 0000000000..7cf786a685
--- /dev/null
+++ b/nczarr_test/run_jsonconvention.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+if test "x$srcdir" = x ; then srcdir=`pwd`; fi 
+. ../test_common.sh
+
+. "$srcdir/test_nczarr.sh"
+
+# This shell script tests support for:
+# read/write using json convention
+
+set -e
+
+testcase() {
+zext=$1
+
+echo "*** Test: write then read using json convention"
+fileargs tmp_jsonconvention "mode=nczarr,$zext"
+deletemap $zext $file
+${NCGEN} -4 -b -o "$fileurl" $srcdir/ref_jsonconvention.cdl
+${NCDUMP} $fileurl > tmp_jsonconvention_${zext}.cdl
+# remove '\n' from ref file before comparing
+rm -f tmp_jsonconvention.cdl
+sed -e 's|\\n||g' < ${srcdir}/ref_jsonconvention.cdl > tmp_jsonconvention.cdl
+diff -b tmp_jsonconvention.cdl tmp_jsonconvention_${zext}.cdl
+}
+
+testcase file
+if test "x$FEATURE_NCZARR_ZIP" = xyes ; then testcase zip; fi
+if test "x$FEATURE_S3TESTS" = xyes ; then testcase s3; fi
+
+exit 0
diff --git a/nczarr_test/zisjson.c b/nczarr_test/zisjson.c
index 186ae45f6c..e13c69f23f 100644
--- a/nczarr_test/zisjson.c
+++ b/nczarr_test/zisjson.c
@@ -7,36 +7,122 @@
    Output 1 or 0.
 */
 
-#include "config.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
 
 #include "stdlib.h"
 #include "stdio.h"
+#include "string.h"
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 
+#if defined(_WIN32) && !defined(__MINGW32__)
+#include "XGetopt.h"
+#else
+#include <getopt.h>
+#endif
+
 #include "netcdf.h"
 #include "nclist.h"
 #include "ncjson.h"
 
 #define MAXREAD 8192
 
+/* Command line options */
+struct Jsonpptions {
+    int trace;
+} jsonoptions;
+
+static const char*
+sortname(int thesort)
+{
+    switch(thesort) {
+    default: break;
+    case NCJ_INT: return "NCJ_INT";
+    case NCJ_DOUBLE: return "NCJ_DOUBLE";
+    case NCJ_BOOLEAN: return "NCJ_BOOLEAN";
+    case NCJ_STRING: return "NCJ_STRING";
+    case NCJ_DICT: return "NCJ_DICT";
+    case NCJ_ARRAY: return "NCJ_ARRAY";
+    case NCJ_NULL: return "NCJ_NULL";
+    }
+    return "?";
+}
+
+
+static void
+jsontrace(NCjson* json, int depth)
+{
+    int i;
+    if(json == NULL) goto done;
+    printf("[%d] sort=%s",depth,sortname(NCJsort(json)));
+    switch(NCJsort(json)) {
+    case NCJ_INT:
+    case NCJ_DOUBLE:
+    case NCJ_BOOLEAN:
+    case NCJ_STRING:
+	printf(" string=|%s|\n",NCJstring(json));
+	break;
+    case NCJ_NULL:
+	printf("\n");
+	break;
+    case NCJ_ARRAY:
+	printf("\n");
+	for(i=0;i<NCJlength(json);i++)
+	    jsontrace(NCJith(json,i),depth+1);
+	break;
+    case NCJ_DICT:
+	printf("\n");
+	for(i=0;i<NCJlength(json);i+=2) {
+	    jsontrace(NCJith(json,i),depth+1);
+	    jsontrace(NCJith(json,i+1),depth+1);
+	} break;
+    default: break;
+    }
+done:
+    return;
+}
+
 int
 main(int argc, char** argv)
 {
     int stat = NC_NOERR;
     char text[MAXREAD+1];
     NCjson* json = NULL;
-    int i, red;
+    int i, red, c;
     FILE* f = NULL;
 
-    if(argc > 1) {
-	/* use argv[1] as input */
-	f = fopen(argv[1],"r");
-	if(f == NULL) {fprintf(stderr,"No such file: %s\n",argv[1]); exit(1);}
-    } else
-        f = stdin;
+    nc_initialize();
+    memset((void*)&jsonoptions,0,sizeof(jsonoptions));
+
+    while ((c = getopt(argc, argv, "t")) != EOF) {
+	switch(c) {
+	case 't': jsonoptions.trace = 1; break;
+	case '?':
+	   fprintf(stderr,"unknown option\n");
+	   exit(1);
+	}
+    }	
+
+    /* get file argument */
+    argc -= optind;
+    argv += optind;
+
+    if (argc > 1) {
+	fprintf(stderr, "zisjson: only one input file argument permitted\n");
+	exit(1);
+    }
+    if (argc == 0)
+	f = stdin;
+    else {
+        /* use argv[0] as input */
+        f = fopen(argv[0],"r");
+        if(f == NULL) {fprintf(stderr,"No such file: %s\n",argv[1]); exit(1);}
+    }
 
     /* Read json from stdin */
     for(i=0;;i++) {
@@ -54,9 +140,12 @@ main(int argc, char** argv)
 	stat = NC_EEMPTY;
     } else {
         stat = NCJparse(text,0,&json);
-	NCJreclaim(json);
+	if(!stat) {
+	    if(jsonoptions.trace) jsontrace(json,0);
+	    NCJreclaim(json);
+	}
     }
-    printf("%d",(stat==NC_NOERR?1:0)); /* parse success|failure */    
+    printf("%d",(stat?0:1)); /* parse success|failure */    
     if(f != stdin) fclose(f);
     return 0;
 }

From 3e2f32a4bcca19fd755bb3c731a05f99e2b8bcce Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@ucar.edu>
Date: Mon, 9 May 2022 14:23:28 -0600
Subject: [PATCH 6/7] update

---
 libnczarr/zsync.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/libnczarr/zsync.c b/libnczarr/zsync.c
index aa564211e9..032ea1c525 100644
--- a/libnczarr/zsync.c
+++ b/libnczarr/zsync.c
@@ -22,7 +22,7 @@ static int ncz_sync_var(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int isclose);
 
 static int ncz_jsonize_atts(NCindex* attlist, NCjson** jattrsp);
 static int load_jatts(NCZMAP* map, NC_OBJ* container, int nczarrv1, NCjson** jattrsp, NClist** atypes);
-static int zconvert(nc_type typeid, size_t typelen, void* dst, NCjson* src);
+static int zconvert(nc_type typeid, size_t typelen, NCjson* src, void* dst);
 static int computeattrinfo(const char* name, NClist* atypes, NCjson* values,
 		nc_type* typeidp, size_t* typelenp, size_t* lenp, void** datap);
 static int parse_group_content(NCjson* jcontent, NClist* dimdefs, NClist* varnames, NClist* subgrps);
@@ -41,7 +41,7 @@ static int computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, s
 static int inferattrtype(NCjson* values, nc_type* typeidp);
 static int mininttype(unsigned long long u64, int negative);
 static int computedimrefs(NC_FILE_INFO_T* file, NC_VAR_INFO_T* var, int purezarr, int xarray, int ndims, NClist* dimnames, size64_t* shapes, NC_DIM_INFO_T** dims);
-static int read_dict(NCjson** valuep);
+static int read_dict(NCjson* jdict, NCjson** jtextp);
 static int write_dict(size_t len, const void* data, NCjson** jsonp);
 
 /**************************************************/
@@ -934,7 +934,7 @@ load_jatts(NCZMAP* map, NC_OBJ* container, int nczarrv1, NCjson** jattrsp, NClis
 
 /* Convert a json value to actual data values of an attribute. */
 static int
-zconvert(nc_type typeid, size_t typelen, void* dst0, NCjson* src)
+zconvert(nc_type typeid, size_t typelen, NCjson* src, void* dst0)
 {
     int stat = NC_NOERR;
     int i;
@@ -1020,6 +1020,7 @@ computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, size_t* lenp
     void* data = NULL;
     size_t typelen;
     nc_type typeid = NC_NAT;
+    NCjson* jtext = NULL;
     int reclaimvalues = 0;
 
     /* Get assumed type */
@@ -1037,7 +1038,9 @@ computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, size_t* lenp
 	break;
     case NCJ_DICT:
 	/* Apply the JSON dictionary convention and convert to string */
-	if((stat = read_dict(&values))) goto done;
+	if((stat = read_dict(values,&jtext))) goto done;
+	values = jtext; jtext = NULL;
+	reclaimvalues = 1;
 	/* fall thru */
     case NCJ_STRING: /* requires special handling as an array of characters; also look out for empty string */
 	if(typeid == NC_CHAR) {
@@ -1060,7 +1063,7 @@ computeattrdata(nc_type* typeidp, NCjson* values, size_t* typelenp, size_t* lenp
         if(data == NULL)
 	    {stat = NC_ENOMEM; goto done;}
         /* convert to target type */
-        if((stat = zconvert(typeid, typelen, data, values)))
+        if((stat = zconvert(typeid, typelen, values, data)))
    	    goto done;
     }
     if(lenp) *lenp = count;
@@ -2322,20 +2325,19 @@ Writing: if the attribute is of type char and looks like a JSON dictionary,
 */
 
 static int
-read_dict(NCjson** jvaluep)
+read_dict(NCjson* jdict, NCjson** jtextp)
 {
     int stat = NC_NOERR;
-    NCjson* jdict = NULL;
     NCjson* jtext = NULL;
     char* text = NULL;
 
-    assert(jvaluep != NULL && *jvaluep != NULL);
-    jdict = *jvaluep;
+    if(jdict == NULL) {stat = NC_EINVAL; goto done;}
     if(NCJsort(jdict) != NCJ_DICT)  {stat = NC_EINVAL; goto done;}
     if(NCJunparse(jdict,0,&text)) {stat = NC_EINVAL; goto done;}
     if(NCJnewstring(NCJ_STRING,text,&jtext)) {stat = NC_EINVAL; goto done;}
-    *jvaluep = jtext;
+    *jtextp = jtext; jtext = NULL;
 done:
+    NCJreclaim(jtext);
     nullfree(text);
     return stat;
 }
@@ -2351,8 +2353,9 @@ write_dict(size_t len, const void* data, NCjson** jsonp)
         {stat = NC_EINVAL; goto done;}
     if(NCJsort(jdict) != NCJ_DICT)
         {stat = NC_EINVAL; goto done;}
-    *jsonp = jdict;
+    *jsonp = jdict; jdict = NULL;
 done:
+    NCJreclaim(jdict);
     return stat;
 }
 

From 8eb0712eb66fa4e7ccc290e63ede276bb8d63f87 Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@ucar.edu>
Date: Mon, 9 May 2022 14:45:06 -0600
Subject: [PATCH 7/7] final1

---
 .github/workflows/run_tests_osx.yml       | 2 +-
 .github/workflows/run_tests_ubuntu.yml    | 2 +-
 .github/workflows/run_tests_win_mingw.yml | 2 +-
 RELEASE_NOTES.md                          | 2 ++
 ncdump/tst_nccopy3.sh                     | 1 -
 ncdump/tst_output.sh                      | 1 -
 6 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/run_tests_osx.yml b/.github/workflows/run_tests_osx.yml
index aa35ae8795..8e9d65a6fb 100644
--- a/.github/workflows/run_tests_osx.yml
+++ b/.github/workflows/run_tests_osx.yml
@@ -7,7 +7,7 @@
 name: Run macOS-based netCDF Tests
 
 
-on: [pull_request,push]
+on: [pull_request]
 
 jobs:
 
diff --git a/.github/workflows/run_tests_ubuntu.yml b/.github/workflows/run_tests_ubuntu.yml
index 826ac43589..a21ac5b001 100644
--- a/.github/workflows/run_tests_ubuntu.yml
+++ b/.github/workflows/run_tests_ubuntu.yml
@@ -4,7 +4,7 @@
 
 name: Run Ubuntu/Linux netCDF Tests
 
-on: [pull_request,push]
+on: [pull_request]
 
 jobs:
 
diff --git a/.github/workflows/run_tests_win_mingw.yml b/.github/workflows/run_tests_win_mingw.yml
index aaf999e6a4..913920a3aa 100644
--- a/.github/workflows/run_tests_win_mingw.yml
+++ b/.github/workflows/run_tests_win_mingw.yml
@@ -7,7 +7,7 @@
 name: Run MSYS2, MinGW64-based Tests
 
 
-on: [pull_request,push]
+on: [pull_request]
 
 jobs:
 
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index f876461b14..157b3d2abf 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -7,6 +7,8 @@ This file contains a high-level description of this package's evolution. Release
 
 ## 4.8.2 - TBD
 
+* [Enhancement] Allow the read/write of JSON-valued Zarr attributes to allow
+for domain specific info such as used by GDAL/Zarr. See [Github #????](https://github.com/Unidata/netcdf-c/pull/????).
 * [Enhancement] Update the documentation to match the current filter capabilities  See [Github #2249](https://github.com/Unidata/netcdf-c/pull/2249).
 * [Enhancement] Support installation of pre-built standard filters into user-specified location. See [Github #2318](https://github.com/Unidata/netcdf-c/pull/2318).
 * [Enhancement] Improve filter support. More specifically (1) add nc_inq_filter_avail to check if a filter is available, (2) add the notion of standard filters, (3) cleanup szip support to fix interaction with NCZarr. See [Github #2245](https://github.com/Unidata/netcdf-c/pull/2245).
diff --git a/ncdump/tst_nccopy3.sh b/ncdump/tst_nccopy3.sh
index 7dcfc910c5..30b53bb8b1 100755
--- a/ncdump/tst_nccopy3.sh
+++ b/ncdump/tst_nccopy3.sh
@@ -8,7 +8,6 @@
 if test "x$srcdir" = x ; then srcdir=`pwd`; fi
 . ../test_common.sh
 
-set -x
 set -e
 
 echo ""
diff --git a/ncdump/tst_output.sh b/ncdump/tst_output.sh
index 18da9c3e6f..40c7e7cd47 100755
--- a/ncdump/tst_output.sh
+++ b/ncdump/tst_output.sh
@@ -4,7 +4,6 @@ if test "x$srcdir" = x ; then srcdir=`pwd`; fi
 . ../test_common.sh
 
 # This shell script tests the output from several previous tests.
-set -x
 set -e
 
 echo ""