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authorLibravatar Jeff King <peff@peff.net>2020-11-10 16:40:19 -0500
committerLibravatar Junio C Hamano <gitster@pobox.com>2020-11-10 13:46:27 -0800
commit3a1f91cfd9633a4f59e0534fa5ba076e031a78ed (patch)
treee170b06a104c26405937bc7225bf43440fcb1305 /Documentation
parentrev-parse: put all options under the "-" check (diff)
downloadtgif-3a1f91cfd9633a4f59e0534fa5ba076e031a78ed.tar.xz
rev-parse: handle --end-of-options
We taught rev-list a new way to separate options from revisions in 19e8789b23 (revision: allow --end-of-options to end option parsing, 2019-08-06), but rev-parse uses its own parser. It should know about --end-of-options not only for consistency, but because it may be presented with similarly ambiguous cases. E.g., if a caller does: git rev-parse "$rev" -- "$path" to parse an untrusted input, then it will get confused if $rev contains an option-like string like "--local-env-vars". Or even "--not-real", which we'd keep as an option to pass along to rev-list. Or even more importantly: git rev-parse --verify "$rev" can be confused by options, even though its purpose is safely parsing untrusted input. On the plus side, it will always fail the --verify part, as it will not have parsed a revision, so the caller will generally "fail closed" rather than continue to use the untrusted string. But it will still trigger whatever option was in "$rev"; this should be mostly harmless, since rev-parse options are all read-only, but I didn't carefully audit all paths. This patch lets callers write: git rev-parse --end-of-options "$rev" -- "$path" and: git rev-parse --verify --end-of-options "$rev" which will both treat "$rev" always as a revision parameter. The latter is a bit clunky. It would be nicer if we had defined "--verify" to require that its next argument be the revision. But we have not historically done so, and: git rev-parse --verify -q "$rev" does currently work. I added a test here to confirm that we didn't break that. A few implementation notes: - We don't document --end-of-options explicitly in commands, but rather in gitcli(7). So I didn't give it its own section in git-rev-parse(1). But I did call it out specifically in the --verify section, and include it in the examples, which should show best practices. - We don't have to re-indent the main option-parsing block, because we can combine our "did we see end of options" check with "does it start with a dash". The exception is the pre-setup options, which need their own block. - We do however have to pull the "--" parsing out of the "does it start with dash" block, because we want to parse it even if we've seen --end-of-options. - We'll leave "--end-of-options" in the output. This is probably not technically necessary, as a careful caller will do: git rev-parse --end-of-options $revs -- $paths and anything in $revs will be resolved to an object id. However, it does help a slightly less careful caller like: git rev-parse --end-of-options $revs_or_paths where a path "--foo" will remain in the output as long as it also exists on disk. In that case, it's helpful to retain --end-of-options to get passed along to rev-list, s it would otherwise see just "--foo". Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/git-rev-parse.txt8
1 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 19b12b6d43..5013daa6ef 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -109,6 +109,10 @@ names an existing object that is a commit-ish (i.e. a commit, or an
annotated tag that points at a commit). To make sure that `$VAR`
names an existing object of any type, `git rev-parse "$VAR^{object}"`
can be used.
++
+Note that if you are verifying a name from an untrusted source, it is
+wise to use `--end-of-options` so that the name argument is not mistaken
+for another option.
-q::
--quiet::
@@ -446,7 +450,7 @@ $ git rev-parse --verify HEAD
* Print the commit object name from the revision in the $REV shell variable:
+
------------
-$ git rev-parse --verify $REV^{commit}
+$ git rev-parse --verify --end-of-options $REV^{commit}
------------
+
This will error out if $REV is empty or not a valid revision.
@@ -454,7 +458,7 @@ This will error out if $REV is empty or not a valid revision.
* Similar to above:
+
------------
-$ git rev-parse --default master --verify $REV
+$ git rev-parse --default master --verify --end-of-options $REV
------------
+
but if $REV is empty, the commit object name from master will be printed.