Does chg cache information?

[Yuya Nishihara]

On Fri, 18 Jan 2019 22:04:20 +0100, Marcus Harnisch wrote:
> To make my life a little less miserable I wrote a semi-automatic bridge
> between Hg and Clearcase (CC) in the form of a bunch of scripts. The Hg
> repo resides in a CC view as unversioned object. To speed up my scripts
> (should be an extension really...) I have switched to chg which improves
> performance considerably. In a second CC view with its own Hg repo I am
> tracking other people's changes. A bit like a vendor branch. Very primitive
> indeed.
> Recently I ran into the odd situation that one Hg repo appeared to have
> lost revisions while the files' contents were up-to-date but shown as
> modified. As if .hg had been restored from an old backup. Read-only
> experimenting in both repos returned inconsistent results. After a bit of
> head scratching I noticed that both shells with their respective CC views
> and corresponding Hg repos were executed on the same machine, thus sharing
> a chg process, which is such an unlikely situation here that I hadn't even
> thought of that before. The thing is that in different CC views, identical
> paths point to different file objects. After making sure that both views
> are accessed on different machines, i.e. different chg instances,
> everything is fine again.
> 
> Is it possible that chg caches information about paths and may have used
> the wrong information when accessed from the other repo? Not looking for a
> fix from your end, just curious if I am on the right track with my
> assumption.

It's unlikely that chg caches repository data. chg daemon process is forked
per connection, and a repository object is loaded after fork(). However,
if an extension does weird thing in uisetup()/extsetup(), the result may
persist.

Since 4.9rc released today, you can dump internal events to log file. It
might help debugging the issue.

  [cmdserver]
  log = /path/to/server.log
  # events to track (default: chgserver, cmdserver, repocache)
  track-log = *

(Note: repocache is new experimental feature and is disabled by default.)