How do I determine if a directory is part of a Subversion working copy?

How do I determine if a directory is part of a Subversion working copy?

This is the same question as on

  https://stackoverflow.com/questions/7172334/how-do-i-determine-if-a-directory-is-part-of-a-subversion-working-copy

but all the answers there except mine are incorrect.

The issue is that one needs to distinguish 3 cases, not 2!

1. Positive answer.
2. Negative answer.
3. Arbitrary error.

So, solutions based on "svn info 2> /dev/null" are incorrect as they
cannot distinguish case 2 and case 3. The error message is important.

I was using such a solution, and it took me some time to find the
cause of an unexpected negative answer: I had a concurrent "svn up"
running in another shell (which I forgot as it was lengthy).

I could check that this was indeed a plausible cause:

joooj:~/wd> while svn info > /dev/null ; do true; done
svn: E200033: Another process is blocking the working copy database, or the underlying filesystem does not support file locking; if the working copy is on a network filesystem, make sure file locking has been enabled on the file server
svn: E200033: sqlite[S5]: database is locked, executing statement 'PRAGMA case_sensitive_like=1;PRAGMA synchronous=OFF;PRAGMA recursive_triggers=ON;PRAGMA foreign_keys=OFF;PRAGMA locking_mode = NORMAL;PRAGMA journal_mode = TRUNCATE;'

when doing "svn up" in another shell.

So I proposed the following script:

------------------------------------------------------------
#!/bin/sh

err=$(LC_ALL=C svn info "$1" 2>&1 >/dev/null)

if [ $? = 0 ]; then
  echo yes
  exit 0
fi

case $err in
  *"is not a working copy")
    echo no
    exit 0 ;;
esac

printf "%s\n" "$err" >&2
exit 1
------------------------------------------------------------

But is there a better solution?

Checking the error message might not be future-proof.

-- 
Vincent Lefèvre <[email protected]> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)