view tests/test-cache-abuse.t @ 30745:c1b7b2285522

revlog: flag processor Add the ability for revlog objects to process revision flags and apply registered transforms on read/write operations. This patch introduces: - the 'revlog._processflags()' method that looks at revision flags and applies flag processors registered on them. Due to the need to handle non-commutative operations, flag transforms are applied in stable order but the order in which the transforms are applied is reversed between read and write operations. - the 'addflagprocessor()' method allowing to register processors on flags. Flag processors are defined as a 3-tuple of (read, write, raw) functions to be applied depending on the operation being performed. - an update on 'revlog.addrevision()' behavior. The current flagprocessor design relies on extensions to wrap around 'addrevision()' to set flags on revision data, and on the flagprocessor to perform the actual transformation of its contents. In the lfs case, this means we need to process flags before we meet the 2GB size check, leading to performing some operations before it happens: - if flags are set on the revision data, we assume some extensions might be modifying the contents using the flag processor next, and we compute the node for the original revision data (still allowing extension to override the node by wrapping around 'addrevision()'). - we then invoke the flag processor to apply registered transforms (in lfs's case, drastically reducing the size of large blobs). - finally, we proceed with the 2GB size check. Note: In the case a cachedelta is passed to 'addrevision()' and we detect the flag processor modified the revision data, we chose to trust the flag processor and drop the cachedelta.
author Remi Chaintron <remi@fb.com>
date Tue, 10 Jan 2017 16:15:21 +0000
parents b0b85d8695cb
children 1cc7c96cad75
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Enable obsolete markers

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution=createmarkers
  > [phases]
  > publish=False
  > EOF

Build a repo with some cacheable bits:

  $ hg init a
  $ cd a

  $ echo a > a
  $ hg ci -qAm0
  $ hg tag t1
  $ hg book -i bk1

  $ hg branch -q b2
  $ hg ci -Am1
  $ hg tag t2

  $ echo dumb > dumb
  $ hg ci -qAmdumb
  $ hg debugobsolete b1174d11b69e63cb0c5726621a43c859f0858d7f

  $ hg phase -pr t1
  $ hg phase -fsr t2

Make a helper function to check cache damage invariants:

- command output shouldn't change
- cache should be present after first use
- corruption/repair should be silent (no exceptions or warnings)
- cache should survive deletion, overwrite, and append
- unreadable / unwriteable caches should be ignored
- cache should be rebuilt after corruption

  $ damage() {
  >  CMD=$1
  >  CACHE=.hg/cache/$2
  >  CLEAN=$3
  >  hg $CMD > before
  >  test -f $CACHE || echo "not present"
  >  echo bad > $CACHE
  >  test -z "$CLEAN" || $CLEAN
  >  hg $CMD > after
  >  diff -u before after || echo "*** overwrite corruption"
  >  echo corruption >> $CACHE
  >  test -z "$CLEAN" || $CLEAN
  >  hg $CMD > after
  >  diff -u before after || echo "*** append corruption"
  >  rm $CACHE
  >  mkdir $CACHE
  >  test -z "$CLEAN" || $CLEAN
  >  hg $CMD > after
  >  diff -u before after || echo "*** read-only corruption"
  >  test -d $CACHE || echo "*** directory clobbered"
  >  rmdir $CACHE
  >  test -z "$CLEAN" || $CLEAN
  >  hg $CMD > after
  >  diff -u before after || echo "*** missing corruption"
  >  test -f $CACHE || echo "not rebuilt"
  > }

Beat up tags caches:

  $ damage "tags --hidden" tags2
  $ damage tags tags2-visible
  $ damage "tag -f t3" hgtagsfnodes1

Beat up hidden cache:

  $ damage log hidden

Beat up branch caches:

  $ damage branches branch2-base "rm .hg/cache/branch2-[vs]*"
  $ damage branches branch2-served "rm .hg/cache/branch2-[bv]*"
  $ damage branches branch2-visible
  $ damage "log -r branch(.)" rbc-names-v1
  $ damage "log -r branch(default)" rbc-names-v1
  $ damage "log -r branch(b2)" rbc-revs-v1

We currently can't detect an rbc cache with unknown names:

  $ damage "log -qr branch(b2)" rbc-names-v1
  --- before	* (glob)
  +++ after	* (glob)
  @@ -1,8 +?,0 @@ (glob)
  -2:5fb7d38b9dc4
  -3:60b597ffdafa
  -4:b1174d11b69e
  -5:6354685872c0
  -6:5ebc725f1bef
  -7:7b76eec2f273
  -8:ef3428d9d644
  -9:ba7a936bc03c
  *** append corruption