Re: [Libguestfs] [PATCH] supermin: dpkg: Handle multiarch setups correctly
On Tue, Mar 04, 2014 at 06:35:27PM +0100, Hilko Bengen wrote:
---
src/dpkg.ml | 39 +++++++++++++++++++++++++--------------
1 file changed, 25 insertions(+), 14 deletions(-)
diff --git a/src/dpkg.ml b/src/dpkg.ml
index c0d3292..2662465 100644
--- a/src/dpkg.ml
+++ b/src/dpkg.ml
@@ -29,6 +29,10 @@ let dpkg_detect () =
Config.apt_get <> "no" &&
file_exists "/etc/debian_version"
+let dpkg_primary_arch =
+ let cmd = sprintf "%s --print-architecture" Config.dpkg in
+ List.hd (run_command_get_lines cmd)
While this is not wrong, if the command returns no lines for some
reason it will cause a mysterious exception to escape which would be
hard to track down. Users would have to know to set an environment
variable to enable stack traces. Thus it is better to write this:
let cmd = ... in
let lines = run_command_get_lines cmd in
match lines with
| [] ->
eprintf "supermin: dpkg: expecting %s to return some output\n" cmd;
exit 1
| arch :: _ -> arch
+ (* On multiarch setups, only consider the primary architecture
*)
+ List.find
+ (fun pkg -> pkg.arch = dpkg_primary_arch || pkg.arch = "all")
+ pkgs
Again, this would let a mysterious exception escape if no matching
match is found. Since this is an internal error, I guess we don't
need an error mesage, but using 'assert false' will cause the file &
line number to be printed, so something like this would be better:
try
List.find (fun pkg -> .....) pkgs
with
Not_found -> assert false
ACK with those changes.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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