[PATCH 2 of 2] localrepo: check for case collisions at commit time (issue4665) (BC)

[Gregory Szorc]

> On Aug 17, 2016, at 22:28, Gregory Szorc <gregory.szorc at gmail.com> wrote:
> 
> # HG changeset patch
> # User Gregory Szorc <gregory.szorc at gmail.com>
> # Date 1471497059 25200
> #      Wed Aug 17 22:10:59 2016 -0700
> # Node ID e8d4db665bf172344d2354c17a0eb8f69ef265c7
> # Parent  04ba5f1f6c28674ed2df750a8acca02021b2698c
> localrepo: check for case collisions at commit time (issue4665) (BC)
> 
> Before, case collisions were only reported when performing `hg add`.
> This meant that many commands that could add or rename files (including
> graft, rebase, histedit, backout, etc) weren't audited for case
> collisions.
> 
> This patch adds case collision detection to the lower-level
> repo.commit() so that any time a commit is performed from the working
> directory state we look for case collisions.
> 
> As the test changes show, this results in a warning or abort at
> `hg commit` time.
> 
> It would arguably be even better to perform case collision detection
> in localrepository.commitctx(), which is the lowest level function
> for adding a new changeset. But I'm not sure if that's appropriate.
> 
> The added code in scmutil.py could likely be consolidated with existing
> code. It's short enough that I'm fine with the DRY violation. But if
> someone wants to push back, I'll understand.
> 
> diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
> --- a/mercurial/localrepo.py
> +++ b/mercurial/localrepo.py
> @@ -1581,16 +1581,24 @@ class localrepository(object):
>                     '.hgsubstate' not in (status.modified + status.added +
>                                           status.removed)):
>                     status.removed.insert(0, '.hgsubstate')
> 
>             # make sure all explicit patterns are matched
>             if not force:
>                 self.checkcommitpatterns(wctx, vdirs, match, status, fail)
> 
> +            # Audit added files for case collisions.
> +            caseabort, casewarn = scmutil.checkportabilityalert(self.ui)
> +            if caseabort or casewarn:
> +                cca = scmutil.ctxcasecollisionauditor(self.ui, wctx.p1(),
> +                                                      caseabort)
> +                for f in status.added:
> +                    cca(f)
> +
>             cctx = context.workingcommitctx(self, status,
>                                             text, user, date, extra)
> 
>             # internal config: ui.allowemptycommit
>             allowemptycommit = (wctx.branch() != wctx.p1().branch()
>                                 or extra.get('close') or merge or cctx.files()
>                                 or self.ui.configbool('ui', 'allowemptycommit'))
>             if not allowemptycommit:
> diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
> --- a/mercurial/scmutil.py
> +++ b/mercurial/scmutil.py
> @@ -202,16 +202,33 @@ class casecollisionauditor(object):
>         if fl in self._loweredfiles and f not in self._dirstate:
>             msg = _('possible case-folding collision for %s') % f
>             if self._abort:
>                 raise error.Abort(msg)
>             self._ui.warn(_("warning: %s\n") % msg)
>         self._loweredfiles.add(fl)
>         self._newfiles.add(f)
> 
> +class ctxcasecollisionauditor(object):
> +    """A case collision auditor that works on a changectx."""
> +    def __init__(self, ui, ctx, abort):
> +        self._ui = ui
> +        self._abort = abort
> +        self._loweredfiles = set(encoding.lower(p) for p in ctx.manifest())

This line has scalability issues. I'm open for suggestions on how to deal with this.

> +
> +    def __call__(self, path):
> +        l = encoding.lower(path)
> +        if l in self._loweredfiles:
> +            msg = _('possible case-folding collision for %s') % path
> +            if self._abort:
> +                raise error.Abort(msg)
> +            self._ui.warn(_('warning: %s\n') % msg)
> +
> +        self._loweredfiles.add(l)
> +
> def filteredhash(repo, maxrev):
>     """build hash of filtered revisions in the current repoview.
> 
>     Multiple caches perform up-to-date validation by checking that the
>     tiprev and tipnode stored in the cache file match the current repository.
>     However, this is not sufficient for validating repoviews because the set
>     of revisions in the view may change without the repository tiprev and
>     tipnode changing.
> diff --git a/tests/test-casecollision.t b/tests/test-casecollision.t
> --- a/tests/test-casecollision.t
> +++ b/tests/test-casecollision.t
> @@ -24,65 +24,88 @@ test file addition with colliding case
>   $ hg forget A
>   $ hg st
>   A a
>   ? A
>   $ hg add --config ui.portablefilenames=no A
>   $ hg st
>   A A
>   A a
> +
> +Abort at commit time when case-folding collisions aren't allowed
> +
> +  $ hg --config ui.portablefilenames=abort commit -m 'add A a'
> +  abort: possible case-folding collision for a
> +  [255]
> +
>   $ hg commit -m 'add A a'
> +  warning: possible case-folding collision for a
> 
>   $ mkdir b
>   $ touch b/c b/D
>   $ hg add b
>   adding b/D
>   adding b/c
>   $ hg commit -m 'add b/c b/D'
> 
>   $ touch b/d b/C
>   $ hg add b/C
>   warning: possible case-folding collision for b/C
>   $ hg add b/d
>   warning: possible case-folding collision for b/d
> -  $ hg commit -m 'add b/C b/d'
> +  $ hg --config ui.portablefilenames=no commit -m 'add b/C b/d'
> 
>   $ touch b/a1 b/a2
>   $ hg add b
>   adding b/a1
>   adding b/a2
>   $ hg commit -m 'add b/a1 b/a2'
> 
>   $ touch b/A2 b/a1.1
>   $ hg add b/a1.1 b/A2
>   warning: possible case-folding collision for b/A2
>   $ hg commit -m 'add b/A2 b/a1.1'
> +  warning: possible case-folding collision for b/A2
> 
>   $ touch b/f b/F
>   $ hg add b/f b/F
>   warning: possible case-folding collision for b/f
>   $ hg commit -m 'add b/f b/F'
> +  warning: possible case-folding collision for b/f
> 
>   $ touch g G
>   $ hg add g G
>   warning: possible case-folding collision for g
>   $ hg commit -m 'add g G'
> +  warning: possible case-folding collision for g
> 
>   $ mkdir h H
>   $ touch h/x H/x
>   $ hg add h/x H/x
>   warning: possible case-folding collision for h/x
>   $ hg commit -m 'add h/x H/x'
> +  warning: possible case-folding collision for h/x
> 
>   $ touch h/s H/s
>   $ hg add h/s
>   $ hg add H/s
>   warning: possible case-folding collision for H/s
>   $ hg commit -m 'add h/s H/s'
> +  warning: possible case-folding collision for h/s
> +
> +commit -A will not double alert
> +
> +  $ mkdir i I
> +  $ touch i/s I/s
> +  $ hg commit -A -m 'add i/s I/s'
> +  adding I/s
> +  adding i/s
> +  warning: possible case-folding collision for i/s
> 
> case changing rename must not warn or abort
> 
>   $ echo c > c
>   $ hg ci -qAmx
>   $ hg mv c C
>   $ hg commit -m 'mv c C'
> +  warning: possible case-folding collision for C
> 
>   $ cd ..