context: use a the nofsauditor when matching file in history (issue4749) Before this change, asking for file from history (eg: 'hg cat -r 42 foo/bar') could fail because of the current content of the working copy (eg: current "foo" being a symlink). As the working copy state have no influence on the content of the history, we can safely skip these checks. The working copy context class have a different 'match' implementation. That implementation still use the repo.auditor will still catch symlink traversal. I've audited all stuff calling "match" and they all go through a ctx in a sensible way. The most unclear case was diff which still seemed okay. You raised my paranoid level today and I double checked through tests. They behave properly. The odds of someone using the wrong (matching with a changectx for operation that will eventually touch the file system) is non-zero because you are never sure of what people will do. But I dunno if we can fight against that. So I would not commit to "never" for "at this level" and "in the future" if someone write especially bad code. However, as a last defense, the vfs itself is running path auditor in all cases outside of .hg/. So I think anything passing the 'matcher' for buggy reason would growl at the vfs layer.

+
−  $ hg init
+
−
+
−  $ cat > a <<EOF
+
−  > a
+
−  > b
+
−  > c
+
−  > EOF
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−  $ hg ci -Am adda
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−  adding a
+
−
+
−  $ cat > a <<EOF
+
−  > d
+
−  > e
+
−  > f
+
−  > EOF
+
−  $ hg ci -m moda
+
−
+
−  $ hg diff --reverse -r0 -r1
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−  diff -r 2855cdcfcbb7 -r 8e1805a3cf6e a
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−  --- a/a	Thu Jan 01 00:00:00 1970 +0000
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−  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
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−  @@ -1,3 +1,3 @@
+
−  -d
+
−  -e
+
−  -f
+
−  +a
+
−  +b
+
−  +c
+
−
+
−  $ cat >> a <<EOF
+
−  > g
+
−  > h
+
−  > EOF
+
−  $ hg diff --reverse --nodates
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−  diff -r 2855cdcfcbb7 a
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−  --- a/a
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−  +++ b/a
+
−  @@ -1,5 +1,3 @@
+
−   d
+
−   e
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−   f
+
−  -g
+
−  -h
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−
+
−should show removed file 'a' as being added
+
−  $ hg revert a
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−  $ hg rm a
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−  $ hg diff --reverse --nodates a
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−  diff -r 2855cdcfcbb7 a
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−  --- /dev/null
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−  +++ b/a
+
−  @@ -0,0 +1,3 @@
+
−  +d
+
−  +e
+
−  +f
+
−
+
−should show added file 'b' as being removed
+
−  $ echo b >> b
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−  $ hg add b
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−  $ hg diff --reverse --nodates b
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−  diff -r 2855cdcfcbb7 b
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−  --- a/b
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−  +++ /dev/null
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−  @@ -1,1 +0,0 @@
+
−  -b