package fetching: elide errors from unpacking that relate to excluded file paths

[andrewrk]

Extracted from #17392.

If any of the file paths associated with these errors:

zig/src/Package/Fetch.zig

Lines 1080 to 1100 in f7bc55c

	.unable_to_create_sym_link => |info| {
	eb.extra.items[note_i] = @intFromEnum(try eb.addErrorMessage(.{
	.msg = try eb.printString("unable to create symlink from '{s}' to '{s}': {s}", .{
	info.file_name, info.link_name, @errorName(info.code),
	}),
	}));
	},
	.unable_to_create_file => |info| {
	eb.extra.items[note_i] = @intFromEnum(try eb.addErrorMessage(.{
	.msg = try eb.printString("unable to create file '{s}': {s}", .{
	info.file_name, @errorName(info.code),
	}),
	}));
	},
	.unsupported_file_type => |info| {
	eb.extra.items[note_i] = @intFromEnum(try eb.addErrorMessage(.{
	.msg = try eb.printString("file '{s}' has unsupported type '{c}'", .{
	info.file_name, @intFromEnum(info.file_type),
	}),
	}));
	},

would be excluded by this filter:

zig/src/Package/Fetch.zig

Lines 1500 to 1518 in f7bc55c

	const Filter = struct {
	include_paths: std.StringArrayHashMapUnmanaged(void) = .{},
	/// sub_path is relative to the package root.
	pub fn includePath(self: Filter, sub_path: []const u8) bool {
	if (self.include_paths.count() == 0) return true;
	if (self.include_paths.contains("")) return true;
	if (self.include_paths.contains(sub_path)) return true;
	// Check if any included paths are parent directories of sub_path.
	var dirname = sub_path;
	while (std.fs.path.dirname(dirname)) |next_dirname| {
	if (self.include_paths.contains(sub_path)) return true;
	dirname = next_dirname;
	}
	return false;
	}
	};

then don't report those errors.

Above, I linked to the code related to tarball unpacking, but the same needs to be done for the other kinds of unpacking too:

• directory tree copying
• fetching from git