AssertionError on DELETE when child links point to yourself #979

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zooko · 2010-03-04T07:24:10Z

zooko commented

2010-03-04 07:24:10 +00:00

USSJoin accidentally made a directory with all of its child links pointing to itself:

[
 "dirnode",
 {
  "rw_uri": "URI:DIR2:qtotg7dsasgg367iigdmloryjy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua",
  "verify_uri":
"URI:DIR2-Verifier:7adhej5azpcfstqm7hozdplqyy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua",
  "ro_uri": "URI:DIR2-RO:gnc3ftwpfi2s63fmupirayl7b4:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua",
  "children": {
   "1": [
    "dirnode",
    {
     "mutable": true,
     "verify_uri":
"URI:DIR2-Verifier:7adhej5azpcfstqm7hozdplqyy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua",
     "ro_uri": "URI:DIR2-RO:gnc3ftwpfi2s63fmupirayl7b4:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua",
     "rw_uri": "URI:DIR2:qtotg7dsasgg367iigdmloryjy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua",
...

At some point he got an AssertionError, attached in HTML format.

USSJoin accidentally made a directory with all of its child links pointing to itself: ``` [ "dirnode", { "rw_uri": "URI:DIR2:qtotg7dsasgg367iigdmloryjy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua", "verify_uri": "URI:DIR2-Verifier:7adhej5azpcfstqm7hozdplqyy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua", "ro_uri": "URI:DIR2-RO:gnc3ftwpfi2s63fmupirayl7b4:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua", "children": { "1": [ "dirnode", { "mutable": true, "verify_uri": "URI:DIR2-Verifier:7adhej5azpcfstqm7hozdplqyy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua", "ro_uri": "URI:DIR2-RO:gnc3ftwpfi2s63fmupirayl7b4:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua", "rw_uri": "URI:DIR2:qtotg7dsasgg367iigdmloryjy:3iblclsl5vvuguthfgyu6r5r6fqz2eakolo5zf5dd4so7uwyqsua", ... ``` At some point he got an AssertionError, attached in HTML format.

zooko added the

labels 2010-03-04 07:24:10 +00:00

zooko added this to the undecided milestone 2010-03-04 07:24:10 +00:00

zooko commented

2010-03-04 07:24:24 +00:00

Attachment error.html (7092 bytes) added

**Attachment** error.html (7092 bytes) added

error.html

6.9 KiB

zooko commented

2010-03-04 08:08:55 +00:00

From the stack trace it looks like USSJoin was attempting to delete one of the child links when it goes this assertion failure.

davidsarah commented

2010-03-25 00:32:04 +00:00

Making such a directory isn't a problem in itself; this definitely looks like a bug in the webapi handling of DELETE.

tahoe-lafs added

code-frontend-web

and removed

code-dirnodes

labels 2010-03-25 00:32:04 +00:00

tahoe-lafs modified the milestone from undecided to 1.7.0

2010-03-25 00:32:04 +00:00

tahoe-lafs changed title from ~~AssertionError when child links point to yourself~~ to AssertionError on DELETE when child links point to yourself

2010-03-25 00:32:04 +00:00

davidsarah commented

2010-03-25 01:08:30 +00:00

The assertion that failed is assert self.parentnode and self.name in DirectoryNodeHandler's [render_DELETE method]source:src/allmydata/web/directory.py#L140, i.e. either self.parentnode or self.name is falsy. Those fields are only set in the constructor, which is only called from [make_handler_for]source:src/allmydata/web/directory.py#L42, so we're looking for a call to make_handler_for with a missing or falsy parentnode or name argument. But there are quite a few calls to that, and the necessary context isn't on the reported stack trace.

I can see how you might get this error by trying to DELETE .../uri/URI:..., I think -- are we sure that USSJoin didn't attempt to do that?

The testgrid is down atm; I'll try some tests of this when it comes back up.

The assertion that failed is `assert self.parentnode and self.name` in DirectoryNodeHandler's [render_DELETE method]source:src/allmydata/web/directory.py#L140, i.e. either `self.parentnode` or `self.name` is falsy. Those fields are only set in the constructor, which is only called from [make_handler_for]source:src/allmydata/web/directory.py#L42, so we're looking for a call to make_handler_for with a missing or falsy `parentnode` or `name` argument. But there are quite a few calls to that, and the necessary context isn't on the reported stack trace. I can see how you might get this error by trying to DELETE `.../uri/URI:...`, I think -- are we sure that USSJoin didn't attempt to do that? The testgrid is down atm; I'll try some tests of this when it comes back up.

zooko modified the milestone from 1.7.0 to soon

2010-06-19 01:33:50 +00:00

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