install: allow options -D and -t to be used together

* src/install.c (install_file_in_file_parents): Factor out the
creation of any parent directories into ...
(mkancesdirs_safe_wd): ... this new function.
(install_file_in_dir): Add the parameter 'mkdir_and_install', and
call the above new function if it evaluates to true.
(main): During parsing of the -t option, move the check whether
the target_directory exists down  after the option parsing loop,
and do not complain about stat(optarg,...) failing if -D was given.
Pass 'mkdir_and_install' to install_file_in_dir().
* doc/coreutils.texi (install invocation): Remove the (false)
restriction that -D would be ignored together with -t.  Instead,
clarify install's new bahavior.
Fix the node's reference in the top-level @direntry for consistency.
* src/install/basic-1.sh: Add tests for the now-allowed combination
of the -D and -t options.
* NEWS: Mention the improvement.

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/install/basic-1.sh b/tests/install/basic-1.sh
index 283426aca..9835d463e 100755
--- a/tests/install/basic-1.sh
+++ b/tests/install/basic-1.sh
@@ -112,4 +112,31 @@ ginstall: creating directory 'sub3/a/b/c'
 'file' -> 'sub3/a/b/c/file'
 EOF
 
+# Test -D together with -t (available since coreutils >= 8.23).
+# Let ginstall create a completely new destination hierarchy.
+ginstall -t sub4/a/b/c -Dv file >out 2>&1 || fail=1
+compare - out <<\EOF || fail=1
+ginstall: creating directory 'sub4'
+ginstall: creating directory 'sub4/a'
+ginstall: creating directory 'sub4/a/b'
+ginstall: creating directory 'sub4/a/b/c'
+'file' -> 'sub4/a/b/c/file'
+EOF
+
+# Ensure that -D with an already existing file as -t's option argument fails.
+touch sub4/file_exists || framework_failure_
+ginstall -t sub4/file_exists -Dv file >out 2>&1 && fail=1
+compare - out <<\EOF || fail=1
+ginstall: target 'sub4/file_exists' is not a directory
+EOF
+
+# Ensure that -D with an already existing directory for -t's option argument
+# succeeds.
+mkdir sub4/dir_exists || framework_failure_
+touch sub4/dir_exists || framework_failure_
+ginstall -t sub4/dir_exists -Dv file >out 2>&1 || fail=1
+compare - out <<\EOF || fail=1
+'file' -> 'sub4/dir_exists/file'
+EOF
+
 Exit $fail