allow group_arguments to take a prefix length

Signed-off-by: Todd Gamblin <tgamblin@llnl.gov>

lib/spack/spack/cmd/__init__.py

@@ -705,7 +705,11 @@ def first_line(docstring):
 
 
 def group_arguments(
-    args: Sequence[str], max_group_size: int = 500, max_group_len: Optional[int] = None
+    args: Sequence[str],
+    *,
+    max_group_size: int = 500,
+    prefix_length: int = 0,
+    max_group_length: Optional[int] = None,
 ) -> Generator[List[str], None, None]:
     """Splits the supplied list of arguments into groups for passing to CLI tools.
 
@@ -722,30 +726,32 @@ def group_arguments(
     Arguments:
         args: list of arguments to split into groups
         max_group_size: max number of elements in any group (default 500)
-        max_group_len: max length of characters that if a group of args is joined by " "
+        prefix_length: length of any additional arguments to be passed before the groups from args;
+            defaults to 0 characters.
+        max_group_length: max length of characters that if a group of args is joined by " "
             On unix, ths defaults to SC_ARG_MAX from sysconf. On Windows the default is
             the max usable for CreateProcess (32,768 chars)
 
     """
-    if max_group_len is None:
-        max_group_len = 32768  # default to the Windows limit
+    if max_group_length is None:
+        max_group_length = 32768  # default to the Windows limit
         if hasattr(os, "sysconf"):
             # sysconf is only on unix and returns -1 if an option isn't present
             sysconf_max = os.sysconf("SC_ARG_MAX")
             if sysconf_max != -1:
-                max_group_len = sysconf_max
+                max_group_length = sysconf_max
 
     group: List[str] = []
-    grouplen, space = 0, 0
+    grouplen, space = prefix_length, 0
     for i, arg in enumerate(args):
         arglen = len(arg)
-        if arglen > max_group_len:
+        if arglen > max_group_length:
             raise ValueError(f"Argument is longer than the maximum command line size: '{arg}'")
 
         next_grouplen = grouplen + arglen + space
-        if len(group) == max_group_size or next_grouplen > max_group_len:
+        if len(group) == max_group_size or next_grouplen > max_group_length:
             yield group
-            group, grouplen, space = [], 0, 0
+            group, grouplen, space = [], prefix_length, 0
 
         group.append(arg)
         grouplen += arglen + space

lib/spack/spack/cmd/pkg.py

@@ -186,7 +186,8 @@ def pkg_grep(args, unknown_args):
         return 0  # no packages to search
 
     # set up iterator and save the first group to ensure we don't end up with a group of size 1
-    groups = spack.cmd.group_arguments(all_paths)
+    prefix_length = len(" ".join(args.grep_args + unknown_args))
+    groups = spack.cmd.group_arguments(all_paths, prefix_length=prefix_length)
 
     # You can force GNU grep to show filenames on every line with -H, but not POSIX grep.
     # POSIX grep only shows filenames when you're grepping 2 or more files.  Since we

lib/spack/spack/test/cmd/pkg.py

@@ -322,7 +322,7 @@ def test_pkg_hash(mock_packages):
 
 
 @pytest.mark.parametrize(
-    ["max_group_size", "max_group_len", "lengths", "error"],
+    ["max_group_size", "max_group_length", "lengths", "error"],
     [
         (3, 1, None, ValueError),
         (3, 13, None, ValueError),
@@ -334,9 +334,9 @@ def test_pkg_hash(mock_packages):
         (4, 56, [4, 4, 2], None),
     ],
 )
-def test_group_arguments(mock_packages, max_group_size, max_group_len, lengths, error):
+def test_group_arguments(mock_packages, max_group_size, max_group_length, lengths, error):
     generator = spack.cmd.group_arguments(
-        group_args, max_group_size=max_group_size, max_group_len=max_group_len
+        group_args, max_group_size=max_group_size, max_group_length=max_group_length
     )
 
     # just check that error cases raise
@@ -349,7 +349,7 @@ def test_group_arguments(mock_packages, max_group_size, max_group_len, lengths,
     assert sum(groups, []) == group_args
     assert [len(group) for group in groups] == lengths
     assert all(
-        sum(len(elt) for elt in group) + (len(group) - 1) <= max_group_len for group in groups
+        sum(len(elt) for elt in group) + (len(group) - 1) <= max_group_length for group in groups
     )