It was reported on IRC that using gdb.parameter('data-directory') doesn't work correctly. The problem is that the data directory is stored in 'gdb_datadir', however the set/show command is associated with a temporary 'staged_gdb_datadir'. When the user does 'set data-directory VALUE', the VALUE is stored in 'staged_gdb_datadir' by GDB, then set_gdb_datadir is called. This in turn calls set_gdb_data_directory to copy the value from staged_gdb_datadir into gdb_datadir. However, set_gdb_data_directory will resolve relative paths, so the value stored in gdb_datadir might not match the value in staged_gdb_datadir. The Python gdb.parameter API fetches the parameter values by accessing the variable associated with the show command, so in this case staged_gdb_datadir. This causes two problems: 1. Initially staged_gdb_datadir is NULL, and remains as such until the user does 'set data-directory VALUE' (which might never happen), but gdb_datadir starts with GDB's default data-directory value. So initially from Python gdb.parameter('data-directory') will return the empty string, even though at GDB's CLI 'show data-directory' prints a real path. 2. If the user does 'set data-directory ./some/relative/path', GDB will resolve the relative path, thus, 'show data-directory' at the CLI will print an absolute path. However, the value is staged_gdb_datadir will still be the relative path, and gdb.parameter('data-directory') from Python will return the relative path. In this commit I fix both of these issues by: 1. Initialising the value in staged_gdb_datadir based on the initial value in gdb_datadir, and 2. In set_gdb_datadir, after calling set_gdb_data_directory, I copy the value in gdb_datadir back into staged_gdb_datadir. With these two changes in place the value in staged_gdb_datadir should always match the value in gdb_datadir, and accessing data-directory from Python should now work correctly. gdb/ChangeLog: * top.c (staged_gdb_datadir): Update comment. (set_gdb_datadir): Copy the value of gdb_datadir back into staged_datadir. (init_main): Initialise staged_gdb_datadir. gdb/testsuite/ChangeLog: * gdb.python/py-parameter.exp: Add test for reading data-directory using gdb.parameter API.