Change default file format to 1.8 (#5949)

Change default file format to 1.8 across various tests and examples, updating file creation and access logic accordingly.

Behavior:
Default file format version changed to 1.8 in H5Pfapl.c.
Updated file creation and access to use 1.8 format in h5ex_g_compact.c and test_file_image.c.
Set earliest file format in multiple test files including cache_tagging.c, dtypes.c, and links.c.
Tests:
Modified expected output in tools/test/misc/expected/*.ls files to reflect new file format locations.
Adjusted test logic in test_file_image.c and cache_tagging.c to accommodate format changes.
Misc:
Added comments and TODOs for future format testing in test_file_image.c.
Minor variable renaming for clarity in test_file_image.c.

Author: fortnern

HDF5Examples/C/H5G/h5ex_g_compact.c

@@ -28,10 +28,17 @@ main(void)
     H5G_info_t ginfo;
     hsize_t    size;
 
+    /*
+     * Set file access property list to use the earliest file format.
+     * This will force the library to create original format groups.
+     */
+    fapl   = H5Pcreate(H5P_FILE_ACCESS);
+    status = H5Pset_libver_bounds(fapl, H5F_LIBVER_EARLIEST, H5F_LIBVER_LATEST);
+
     /*
      * Create file 1.  This file will use original format groups.
      */
-    file  = H5Fcreate(FILENAME1, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    file  = H5Fcreate(FILENAME1, H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
     group = H5Gcreate(file, GROUP, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
 
     /*
@@ -72,16 +79,16 @@ main(void)
     status = H5Fclose(file);
 
     /*
-     * Set file access property list to allow the latest file format.
-     * This will allow the library to create new compact format groups.
+     * Now use the default file access property list to allow the latest file
+     * format. This will allow the library to create new compact format groups.
+     * Since HDF5 2.0, the default is to use the 1.8 file format as the low
+     * bound, which includes compact groups.
      */
-    fapl   = H5Pcreate(H5P_FILE_ACCESS);
-    status = H5Pset_libver_bounds(fapl, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST);
 
     /*
-     * Create file 2 using the new file access property list.
+     * Create file 2 using the default access property list.
      */
-    file  = H5Fcreate(FILENAME2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
+    file  = H5Fcreate(FILENAME2, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
     group = H5Gcreate(file, GROUP, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
 
     /*

c++/test/tfile.cpp

@@ -80,7 +80,7 @@ test_file_create()
     H5File *file1 = NULL;
     try {
         // Create file FILE1
-        file1 = new H5File(FILE1, H5F_ACC_EXCL);
+        file1 = new H5File(FILE1, H5F_ACC_TRUNC);
 
         // Try to create the same file with H5F_ACC_TRUNC. This should fail
         // because file1 is the same file and is currently open.
@@ -847,8 +847,10 @@ test_file_info()
     H5F_fspace_strategy_t out_strategy = H5F_FSPACE_STRATEGY_FSM_AGGR;
 
     try {
-        // Create a file using default properties.
-        H5File tempfile(FILE7, H5F_ACC_TRUNC);
+        // Create a file using the earliest format.
+        FileAccPropList fapl;
+        fapl.setLibverBounds(H5F_LIBVER_EARLIEST, H5F_LIBVER_LATEST);
+        H5File tempfile(FILE7, H5F_ACC_TRUNC, FileCreatPropList::DEFAULT, fapl);
 
         // Get the file's version information.
         H5F_info2_t finfo;

c++/test/tlinks.cpp

@@ -666,7 +666,7 @@ test_visit(hid_t fapl_id, bool new_format)
         delete file;
 
         // Reopen the file and group in the file.
-        file  = new H5File(filename, H5F_ACC_RDWR);
+        file  = new H5File(filename, H5F_ACC_RDWR, FileCreatPropList::DEFAULT, fapl);
         group = new Group(file->openGroup("Data"));
 
         // Open the group

fortran/test/tH5F.F90

@@ -1145,7 +1145,7 @@ SUBROUTINE file_space(filename, cleanup, total_error)
 
     CALL h5fget_freespace_f(fid, free_space, error)
     CALL check("h5fget_freespace_f",error,total_error)
-    IF(error .EQ.0 .AND. free_space .NE. 1248) THEN
+    IF(error .EQ.0 .AND. free_space .NE. 1853) THEN
        total_error = total_error + 1
        WRITE(*,*) "1: Wrong amount of free space reported, ", free_space
     ENDIF
@@ -1161,7 +1161,7 @@ SUBROUTINE file_space(filename, cleanup, total_error)
     ! Check the free space now
     CALL h5fget_freespace_f(fid, free_space, error)
     CALL check("h5fget_freespace_f",error,total_error)
-    IF(error .EQ.0 .AND. free_space .NE. 216) THEN
+    IF(error .EQ.0 .AND. free_space .NE. 1706) THEN
        total_error = total_error + 1
        WRITE(*,*) "2: Wrong amount of free space reported, ", free_space
     ENDIF
@@ -1173,7 +1173,7 @@ SUBROUTINE file_space(filename, cleanup, total_error)
     ! Check the free space now
     CALL h5fget_freespace_f(fid, free_space, error)
     CALL check("h5fget_freespace_f",error,total_error)
-    IF(error .EQ.0 .AND. free_space .NE. 1248) THEN
+    IF(error .EQ.0 .AND. free_space .NE. 1853) THEN
        total_error = total_error + 1
        WRITE(*,*) "3: Wrong amount of free space reported, ", free_space
     ENDIF

hl/test/test_file_image.c

@@ -52,8 +52,12 @@
 static int
 test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
 {
-    hid_t  *file_id = NULL, *dset_id = NULL, file_space, plist; /* HDF5 ids */
-    hsize_t dims1[RANK]    = {2, 3};                            /* original dimension of datasets */
+    hid_t  *file_id        = NULL;            /* Array of file IDs */
+    hid_t  *dset_id        = NULL;            /* Array of dataset IDs */
+    hid_t   file_space_id  = H5I_INVALID_HID; /* Dataspace ID */
+    hid_t   dcpl_id        = H5I_INVALID_HID; /* DCPL ID */
+    hid_t   fapl_id        = H5I_INVALID_HID; /* FAPL ID */
+    hsize_t dims1[RANK]    = {2, 3};          /* original dimension of datasets */
     hsize_t max_dims[RANK] = {H5S_UNLIMITED, H5S_UNLIMITED};
     int     data1[6]       = {1, 2, 3, 4, 5, 6};    /* original contents of dataset */
     int     data2[6]       = {7, 8, 9, 10, 11, 12}; /* "wrong" contents of dataset */
@@ -99,6 +103,13 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
     if (NULL == (dset_id = (hid_t *)malloc(sizeof(hid_t) * open_images)))
         FAIL_PUTS_ERROR("malloc() failed");
 
+    /* Create FAPL and set earliest format */
+    /* TODO: run this test with all different formats */
+    if ((fapl_id = H5Pcreate(H5P_FILE_ACCESS)) < 0)
+        FAIL_PUTS_ERROR("H5Pcreate() failed");
+    if (H5Pset_libver_bounds(fapl_id, H5F_LIBVER_EARLIEST, H5F_LIBVER_LATEST) < 0)
+        FAIL_PUTS_ERROR("H5Pset_libver_bounds() failed");
+
     HL_TESTING2("get file images");
 
     /* create several file images */
@@ -117,24 +128,24 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
         snprintf(filename[i], filenamelength, "image_file%d.h5", (int)i);
 
         /* create file */
-        if ((file_id[i] = H5Fcreate(filename[i], H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+        if ((file_id[i] = H5Fcreate(filename[i], H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id)) < 0)
             FAIL_PUTS_ERROR("H5Fcreate() failed");
 
         /* define dataspace for the dataset */
-        if ((file_space = H5Screate_simple(RANK, dims1, max_dims)) < 0)
+        if ((file_space_id = H5Screate_simple(RANK, dims1, max_dims)) < 0)
             FAIL_PUTS_ERROR("H5Screate_simple() failed");
 
         /* create dataset property list */
-        if ((plist = H5Pcreate(H5P_DATASET_CREATE)) < 0)
+        if ((dcpl_id = H5Pcreate(H5P_DATASET_CREATE)) < 0)
             FAIL_PUTS_ERROR("H5Pcreate() failed");
 
         /* set property list to create chunked dataset */
-        if (H5Pset_chunk(plist, RANK, dims1) < 0)
+        if (H5Pset_chunk(dcpl_id, RANK, dims1) < 0)
             FAIL_PUTS_ERROR("H5Pset_chunk() failed");
 
         /* create and write an integer type dataset named "dset" */
-        if ((dset_id[i] = H5Dcreate2(file_id[i], DSET_NAME, H5T_NATIVE_INT, file_space, H5P_DEFAULT, plist,
-                                     H5P_DEFAULT)) < 0)
+        if ((dset_id[i] = H5Dcreate2(file_id[i], DSET_NAME, H5T_NATIVE_INT, file_space_id, H5P_DEFAULT,
+                                     dcpl_id, H5P_DEFAULT)) < 0)
             FAIL_PUTS_ERROR("H5Dcreate() failed");
 
         /* dataset in open image 1 is written with "wrong" data */
@@ -153,11 +164,11 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
             FAIL_PUTS_ERROR("H5Fflush() failed");
 
         /* close dataset property list */
-        if (H5Pclose(plist) < 0)
+        if (H5Pclose(dcpl_id) < 0)
             FAIL_PUTS_ERROR("H5Pclose() failed");
 
         /* close dataspace */
-        if (H5Sclose(file_space) < 0)
+        if (H5Sclose(file_space_id) < 0)
             FAIL_PUTS_ERROR("H5Sclose() failed");
 
         /* close dataset */
@@ -277,11 +288,11 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
             FAIL_PUTS_ERROR("H5Dopen() failed");
 
         /* get dataspace for the dataset */
-        if ((file_space = H5Dget_space(dset_id[i])) < 0)
+        if ((file_space_id = H5Dget_space(dset_id[i])) < 0)
             FAIL_PUTS_ERROR("H5Dget_space() failed");
 
         /* get dimensions for the dataset */
-        if (H5Sget_simple_extent_dims(file_space, dims3, NULL) < 0)
+        if (H5Sget_simple_extent_dims(file_space_id, dims3, NULL) < 0)
             FAIL_PUTS_ERROR("H5Sget_simple_extent_dims() failed");
 
         /* read dataset */
@@ -312,7 +323,7 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
         } /* end else */
 
         /* close dataspace */
-        if (H5Sclose(file_space) < 0)
+        if (H5Sclose(file_space_id) < 0)
             FAIL_PUTS_ERROR("H5Sclose() failed");
     } /* end for */
 
@@ -455,11 +466,11 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
             FAIL_PUTS_ERROR("H5Dopen() failed");
 
         /* get dataspace for the dataset */
-        if ((file_space = H5Dget_space(dset_id[i])) < 0)
+        if ((file_space_id = H5Dget_space(dset_id[i])) < 0)
             FAIL_PUTS_ERROR("H5Dget_space() failed");
 
         /* get dimensions for the dataset */
-        if (H5Sget_simple_extent_dims(file_space, dims3, NULL) < 0)
+        if (H5Sget_simple_extent_dims(file_space_id, dims3, NULL) < 0)
             FAIL_PUTS_ERROR("H5Sget_simple_extent_dims() failed");
 
         /* read dataset */
@@ -479,7 +490,7 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
                     FAIL_PUTS_ERROR("comparison of image values with original data failed");
 
         /* close dataspace */
-        if (H5Sclose(file_space) < 0)
+        if (H5Sclose(file_space_id) < 0)
             FAIL_PUTS_ERROR("H5Sclose() failed");
 
         /* close dataset */
@@ -513,6 +524,10 @@ test_file_image(size_t open_images, size_t nflags, const unsigned *flags)
 
     } /* end for */
 
+    /* close file access property list */
+    if (H5Pclose(fapl_id) < 0)
+        FAIL_PUTS_ERROR("H5Pclose() failed");
+
     /* release temporary working buffers */
     for (i = 0; i < open_images; i++)
         free(filename[i]);

java/test/TestH5Fbasic.java

@@ -293,7 +293,7 @@ public void testH5Fget_mdc_size()
         catch (Throwable err) {
             fail("H5.H5Fget_mdc_size: " + err);
         }
-        assertTrue("H5.H5Fget_mdc_size #:" + nentries, nentries == 4);
+        assertTrue("H5.H5Fget_mdc_size #:" + nentries, nentries == 2);
     }
 
     // TODO: test more cases of different cache sizes.

java/test/TestH5Fparams.java

@@ -210,7 +210,7 @@ public void testH5Fget_info()
 
             try {
                 H5F_info2_t finfo = H5.H5Fget_info(fid);
-                assertEquals(finfo.super_version, 0);
+                assertEquals(finfo.super_version, 2);
                 assertEquals(finfo.free_version, 0);
                 assertEquals(finfo.sohm_version, 0);
             }

java/test/TestH5P.java

@@ -1038,7 +1038,7 @@ public void testH5P_userblock()
 
             /* Get the file's version information */
             H5F_info2_t finfo = H5.H5Fget_info(H5fid);
-            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 0);
+            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 2);
             assertTrue("free-space manager version: " + finfo.free_version, finfo.free_version == 0);
             assertTrue("shared object header version: " + finfo.sohm_version, finfo.sohm_version == 0);
             H5.H5Pget_userblock(fcpl_id, size);
@@ -1074,7 +1074,7 @@ public void testH5P_sizes()
 
             /* Get the file's version information */
             H5F_info2_t finfo = H5.H5Fget_info(H5fid);
-            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 0);
+            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 2);
             assertTrue("free-space manager version: " + finfo.free_version, finfo.free_version == 0);
             assertTrue("shared object header version: " + finfo.sohm_version, finfo.sohm_version == 0);
             H5.H5Pget_sizes(fcpl_id, size);
@@ -1111,7 +1111,7 @@ public void testH5P_sym_k()
 
             /* Get the file's version information */
             H5F_info2_t finfo = H5.H5Fget_info(H5fid);
-            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 0);
+            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 2);
             assertTrue("free-space manager version: " + finfo.free_version, finfo.free_version == 0);
             assertTrue("shared object header version: " + finfo.sohm_version, finfo.sohm_version == 0);
             H5.H5Pget_sym_k(fcpl_id, size);
@@ -1148,7 +1148,7 @@ public void testH5P_istore_k()
 
             /* Get the file's version information */
             H5F_info2_t finfo = H5.H5Fget_info(H5fid);
-            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 1);
+            assertTrue("super block version: " + finfo.super_version, finfo.super_version == 2);
             assertTrue("free-space manager version: " + finfo.free_version, finfo.free_version == 0);
             assertTrue("shared object header version: " + finfo.sohm_version, finfo.sohm_version == 0);
             H5.H5Pget_istore_k(fcpl_id, size);

java/test/TestH5Pfapl.java

@@ -412,7 +412,7 @@ public void testH5Pget_libver_bounds()
         }
         assertTrue("testH5Pget_libver_bounds", ret_val >= 0);
         // Check the Earliest Version if the library
-        assertEquals(HDF5Constants.H5F_LIBVER_EARLIEST, libver[0]);
+        assertEquals(HDF5Constants.H5F_LIBVER_V18, libver[0]);
         // Check the Latest Version if the library
         assertEquals(HDF5Constants.H5F_LIBVER_LATEST, libver[1]);
     }

release_docs/CHANGELOG.md

@@ -51,6 +51,10 @@ For releases prior to version 2.0.0, please see the release.txt file and for mor
 
 # ⚠️ Breaking Changes
 
+### Updated default file format to 1.8
+
+   By default, HDF5 will now use the 1.8 file format (`H5F_LIBVER_V18`). This provides improved performance and space efficiency, particularly with groups and links. However, HDF5 library versions 1.6 and earlier will not be able to read files created with the default settings. The previous behavior can be restored using `H5Pset_libver_bounds(fapl_id, H5F_LIBVER_EARLIEST, H5F_LIBVER_LATEST)`.
+
 ### Renamed the option: `HDF5_ENABLE_Z_LIB_SUPPORT`
 
    The option has been renamed to `HDF5_ENABLE_ZLIB_SUPPORT` to be consistent with the naming of other options. Also, the option defaults to OFF. This requires the user to explicitly enable zlib support when configuring the library.
@@ -59,6 +63,10 @@ For releases prior to version 2.0.0, please see the release.txt file and for mor
 
    CMake is now the build system available in HDF5 code. Version 3.26 or later is required. See the AutotoolsToCMakeOptions.md file for highlights of the CMake HDF5 install layout and CMake options to use in place of former Autotools options.
 
+### Fixed problems with family driver and user block
+
+   When using a user block with the family driver, the driver would inappropriately subtract the user block size for each member file when calculating member EOAs. This could cause a failure when an address overflowed the calculated eoa. The driver would also add the user block size when returning the EOF. Modified the family driver to not consider the user block, as it is handled by the H5FD layer. The user block now spans the first X bytes of the family array, for example a 4 KiB user block with 3 KiB member size will take up the entire first member and the first 1 KiB of the second. This may cause compatibility issues with preexisting family files with user blocks, though the way it worked before was inconsistent if it worked at all.
+
 # 🚀 New Features & Improvements
 
 ## Configuration
@@ -185,6 +193,10 @@ All other HDF5 library CMake options are prefixed with `HDF5_`
 
 ## Library
 
+### Updated default file format to 1.8
+
+   By default, HDF5 will now use the 1.8 file format (`H5F_LIBVER_V18`). This provides improved performance and space efficiency, particularly with groups and links. This behavior can be overridden with `H5Pset_libver_bounds()`.
+
 ### Added predefined datatypes for bfloat16 data
 
    Predefined datatypes have been added for little- and big-endian bfloat16 (https://en.wikipedia.org/wiki/Bfloat16_floating-point_format) data.
@@ -557,6 +569,10 @@ Added Fortran wrapper h5fdsubfiling_get_file_mapping_f() for the subfiling file
 
 ## Library
 
+### Fixed problems with family driver and user block
+
+   When using a user block with the family driver, the driver would inappropriately subtract the user block size for each member file when calculating member EOAs. This could cause a failure when an address overflowed the calculated eoa. The driver would also add the user block size when returning the EOF. Modified the family driver to not consider the user block, as it is handled by the H5FD layer. The user block now spans the first X bytes of the family array, for example a 4 KiB user block with 3 KiB member size will take up the entire first member and the first 1 KiB of the second. This may cause compatibility issues with preexisting family files with user blocks, though the way it worked before was inconsistent if it worked at all.
+
 ### Fixed security issue CVE-2025-7067
 
    Fixed a heap buffer overflow in H5FS__sinfo_serialize_node_cb() by discarding file free space sections from the file free space manager when they are found to be invalid. Specifically crafted HDF5 files can result in an attempt to insert duplicate or overlapping file free space sections into a file free space manager, later resulting in a buffer overflow when the same free space section is serialized to the file multiple times.