[PATCH] Avoid bug in Solaris xpg4/sed as used in submodule

The sed provided by Solaris in /usr/xpg4/bin has a bug whereby an unanchored regex using * for zero or more repetitions sees two separate matches fed to the substitution engine in some cases.

This is evidenced by:

$ for sed in /usr/xpg4/bin/sed /usr/bin/sed /opt/csw/gnu/sed; do \ echo 'ab' | $sed -e 's|[a]*|X|g'; \ done XXbX XbX XbX

This bug was triggered during a git submodule clone operation as exercised in the setup stage of t5526-fetch-submodules when using the default SANE_TOOL_PATH for Solaris. It led to paths such as ..../.. being used in the submodule .git gitdir reference.

Using the expression 's|\([^/]*\(/*\)\)|..\2|g' provides the desired result with all three three tested sed implementations but is harder to read. As we do not need to handle fully qualified paths though, the expression could actually be [^/]+ which isn't properly handled either. Instead, use [^/][^/]*, as suggested by Andreas Schwab, which works on all three tested sed implementations.

The new expression is semantically different than the original one. It will not place a leading '..' on a fully qualified path as the original expression did. All of the paths being passed through this regex are relative and did not rely on this behaviour so it's a safe change.

Signed-off-by: Ben Walton <bwalton@artsci.utoronto.ca>
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 git-submodule.sh |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)