tests/test-convert-svn-branches.t

bdiff: balance recursion to avoid quadratic behavior (issue4704)

For highly structured files like JSON or XML dumps with large numbers
of duplicate lines (eg braces) and isolated matching lines, bdiff
could find large numbers of equally good spans. Because it prefers
earlier matches, this would result in pathologically unbalance
recursion that resulted in quadratic performance.

This patch makes it prefer matches closer to the middle that tend to
balance recursion. This change improves the speed of a pathological
test case from 1100s to 9s.

Included is a smaller test that has a roughly 50x safety margin on the
performance it accepts. It's likely to fail on pure builds because
difflib also has a recursion-balancing problem.

#require svn svn-bindings

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > convert =
  > EOF

  $ svnadmin create svn-repo
  $ svnadmin load -q svn-repo < "$TESTDIR/svn/branches.svndump"

Convert trunk and branches

  $ cat > branchmap <<EOF
  > old3 newbranch
  > 
  > 
  > EOF
  $ hg convert --branchmap=branchmap --datesort -r 10 svn-repo A-hg
  initializing destination A-hg repository
  scanning source...
  sorting...
  converting...
  10 init projA
  9 hello
  8 branch trunk, remove c and dir
  7 change a
  6 change b
  5 move and update c
  4 move and update c
  3 change b again
  2 move to old2
  1 move back to old
  0 last change to a

Test template keywords

  $ hg -R A-hg log --template '{rev} {svnuuid}{svnpath}@{svnrev}\n'
  10 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@10
  9 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@9
  8 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old2@8
  7 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@7
  6 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@6
  5 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@6
  4 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@5
  3 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@4
  2 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@3
  1 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@2
  0 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@1

Convert again

  $ hg convert --branchmap=branchmap --datesort svn-repo A-hg
  scanning source...
  sorting...
  converting...
  0 branch trunk@1 into old3

  $ cd A-hg
  $ hg log -G --template 'branch={branches} {rev} {desc|firstline} files: {files}\n'
  o  branch=newbranch 11 branch trunk@1 into old3 files:
  |
  | o  branch= 10 last change to a files: a
  | |
  | | o  branch=old 9 move back to old files:
  | | |
  | | o  branch=old2 8 move to old2 files:
  | | |
  | | o  branch=old 7 change b again files: b
  | | |
  | o |  branch= 6 move and update c files: b
  | | |
  | | o  branch=old 5 move and update c files: c
  | | |
  | | o  branch=old 4 change b files: b
  | | |
  | o |  branch= 3 change a files: a
  | | |
  | | o  branch=old 2 branch trunk, remove c and dir files: c
  | |/
  | o  branch= 1 hello files: a b c dir/e
  |/
  o  branch= 0 init projA files:
  

  $ hg branches
  newbranch                     11:a6d7cc050ad1
  default                       10:6e2b33404495
  old                            9:93c4b0f99529
  old2                           8:b52884d7bead (inactive)
  $ hg tags -q
  tip
  $ cd ..

Test hg failing to call itself

  $ HG=foobar hg convert svn-repo B-hg 2>&1 | grep abort
  abort: Mercurial failed to run itself, check hg executable is in PATH

Convert 'trunk' to branch other than 'default'

  $ cat > branchmap <<EOF
  > default hgtrunk
  > 
  > 
  > EOF
  $ hg convert --branchmap=branchmap --datesort -r 10 svn-repo C-hg
  initializing destination C-hg repository
  scanning source...
  sorting...
  converting...
  10 init projA
  9 hello
  8 branch trunk, remove c and dir
  7 change a
  6 change b
  5 move and update c
  4 move and update c
  3 change b again
  2 move to old2
  1 move back to old
  0 last change to a

  $ cd C-hg
  $ hg branches --template '{branch}\n'
  hgtrunk
  old
  old2
  $ cd ..