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Differential D6612

tests: show the files fields of changelogs for many merges
ClosedPublic

Authored by valentin.gatienbaron on Jul 7 2019, 12:18 PM.

Details

Reviewers
durin42
Group Reviewers
hg-reviewers
Commits
rHG20d0e59be79b: tests: show the files fields of changelogs for many merges
rHGcd40411bc384: tests: show the files fields of changelogs for many merges
Summary

I don't think there's coverage for many of the subtle cases, and I
found it hard to understand what the code is doing by reading it. The
test takes 40s to run on a laptop, or 9s with --chg.

I have yet to find a description of what the files field is supposed
to be for merges. I thought it could be one of:

  1. the files added/modified/removed relative to p1 (wouldn't seem useful, but hg diff -c -r mergerev has this behavior)
  2. the files with filelog nodes not in either parent (i.e., what is

needed to create a bundle out of a commit)

  1. the files added/removed/modified files by merge itself [1]

It's clearly not 1, because file contents merges are symmetric. It's
clearly not 2 because removed files and exec bit changes are
listed. It's also not 3 but I think it's intended to be 3 and the
differences are bugs.

Assuming 3, the test shows that, for merges, the list of files both
overapproximates and underapproximates. All the cases involve file
changes not in the filelog but in the manifest (existence of file
at revision, exec bit and file vs symlink).

I didn't look at all underapproximations, but they looked minor. The
two overapproximations are problematic though because they both cause
potentially long lists of files when merging cleanly.

[1] even what it means for the merge commit itself to change a file is
not completely trivial. A file in the merge being the same as in one
of the parent is too lax as it would consider that merges change
nothing when they revert all the changes done on one side. The
criteria used in the test and in the next commit for "merge didn't
touch a file" is:

  • the parents and the merge all have the same file
  • or, one parent didn't touch the file and the other parent contains the same file as the merge

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

durin42 added subscribers: martinvonz, durin42.Jul 17 2019, 6:23 PM

I know @martinvonz has been looking at files in changelogs recently. Do you have an opinion on this? It looks fine to me.

durin42 accepted this revision as: durin42.Jul 17 2019, 6:25 PM

(Martin, this looks fine to me, if you've got no objections let's include it in 5.1)

martinvonz added a comment.Jul 17 2019, 6:36 PM
In D6612#97313, @durin42 wrote:

(Martin, this looks fine to me, if you've got no objections let's include it in 5.1)

Yes, I agree. I wish there had been a clear and simple definition of what {files} should contain (as there is for {file_adds} and {file_dels} since https://www.mercurial-scm.org/repo/hg/rev/0c72eddb4be5). I spent some time trying to think of something, but I don't have a better proposal than what Valentin did in the next patch, so I think this is good. Great testing too.

valentin.gatienbaron added a commit: rHGcd40411bc384: tests: show the files fields of changelogs for many merges.Jul 18 2019, 12:59 AM
This revision was not accepted when it landed; it landed in state Needs Review.
Closed by commit rHGcd40411bc384: tests: show the files fields of changelogs for many merges (authored by valentin.gatienbaron). · Explain Why
This revision was automatically updated to reflect the committed changes.
valentin.gatienbaron added a comment.Jul 18 2019, 8:16 AM

Thanks! I didn't expect this would make it for 5.1.

Revision Contents
Changeset List

PathPackages
AMtests/test-merge-combination.t (220 lines)

Diff 15948

tests/test-merge-combination.t

  • This file was added.
This file shows what hg says are "modified" files for a merge commit
(hg log -T {files}), somewhat exhaustively.
It shows merges that involves files contents changing, and merges that
involve executable bit changing, but not merges with multiple or zero
merge ancestors, nor copies/renames, and nor identical file contents
with different filelog revisions.
genmerges is the workhorse. Given:
- a range function describing the possible values for file a
- a isgood function to filter out uninteresting combination
- a createfile function to actually write the values for file a on the
filesystem
it print a series of lines that look like: abcd C: output of -T {files}
describing the file a at respectively the base, p2, p1, merge
revision. "C" indicates that hg merge had conflicts.
$ genmerges () {
> for base in `range` -; do
> for r1 in `range $base` -; do
> for r2 in `range $base $r1` -; do
> for m in `range $base $r1 $r2` -; do
> line="$base$r1$r2$m"
> isgood $line || continue
> hg init repo
> cd repo
> make_commit () {
> v=$1; msg=$2; file=$3;
> if [ $v != - ]; then
> createfile $v
> else
> if [ -f a ]
> then rm a
> else touch $file
> fi
> fi
> hg commit -q -Am $msg || exit 123
> }
> echo foo > foo
> make_commit $base base b
> make_commit $r1 r1 c
> hg up -r 0 -q
> make_commit $r2 r2 d
> hg merge -q -r 1 > ../output 2>&1
> if [ $? -ne 0 ]; then rm -f *.orig; hg resolve -m --all -q; fi
> if [ -s ../output ]; then conflicts=" C"; else conflicts=" "; fi
> make_commit $m m e
> if [ $m = $r1 ] && [ $m = $r2 ]
> then expected=
> elif [ $m = $r1 ]
> then if [ $base = $r2 ]
> then expected=
> else expected=a
> fi
> elif [ $m = $r2 ]
> then if [ $base = $r1 ]
> then expected=
> else expected=a
> fi
> else expected=a
> fi
> got=`hg log -r 3 --template '{files}\n' | tr --delete 'e '`
> if [ "$got" = "$expected" ]
> then echo "$line$conflicts: agree on \"$got\""
> else echo "$line$conflicts: hg said \"$got\", expected \"$expected\""
> fi
> cd ../
> rm -rf repo
> done
> done
> done
> done
> }
All the merges of various file contents.
$ range () {
> max=0
> for i in $@; do
> if [ $i = - ]; then continue; fi
> if [ $i -gt $max ]; then max=$i; fi
> done
> $TESTDIR/seq.py `expr $max + 1`
> }
$ isgood () { true; }
$ createfile () {
> if [ -f a ] && [ "`cat a`" = $1 ]
> then touch $file
> else echo $v > a
> fi
> }
$ genmerges
1111 : agree on ""
1112 : agree on "a"
111- : agree on "a"
1121 : agree on "a"
1122 : agree on ""
1123 : agree on "a"
112- : agree on "a"
11-1 : hg said "", expected "a"
11-2 : agree on "a"
11-- : agree on ""
1211 : agree on "a"
1212 : agree on ""
1213 : agree on "a"
121- : agree on "a"
1221 : agree on "a"
1222 : agree on ""
1223 : agree on "a"
122- : agree on "a"
1231 C: agree on "a"
1232 C: agree on "a"
1233 C: agree on "a"
1234 C: agree on "a"
123- C: agree on "a"
12-1 C: agree on "a"
12-2 C: hg said "", expected "a"
12-3 C: agree on "a"
12-- C: agree on "a"
1-11 : hg said "", expected "a"
1-12 : agree on "a"
1-1- : hg said "a", expected ""
1-21 C: agree on "a"
1-22 C: hg said "", expected "a"
1-23 C: agree on "a"
1-2- C: agree on "a"
1--1 : agree on "a"
1--2 : agree on "a"
1--- : agree on ""
-111 : agree on ""
-112 : agree on "a"
-11- : agree on "a"
-121 C: agree on "a"
-122 C: agree on "a"
-123 C: agree on "a"
-12- C: agree on "a"
-1-1 : agree on ""
-1-2 : agree on "a"
-1-- : agree on "a"
--11 : agree on ""
--12 : agree on "a"
--1- : agree on "a"
---1 : agree on "a"
---- : agree on ""
All the merges of executable bit.
$ range () {
> max=a
> for i in $@; do
> if [ $i = - ]; then continue; fi
> if [ $i > $max ]; then max=$i; fi
> done
> if [ $max = a ]; then echo f; else echo f x; fi
> }
$ isgood () { case $line in *f*x*) true;; *) false;; esac; }
$ createfile () {
> if [ -f a ] && (([ -x a ] && [ $v = x ]) || (! [ -x a ] && [ $v != x ]))
> then touch $file
> else touch a; if [ $v = x ]; then chmod +x a; else chmod -x a; fi
> fi
> }
#if execbit
$ genmerges
fffx : agree on "a"
ffxf : agree on "a"
ffxx : agree on ""
ffx- : agree on "a"
ff-x : hg said "", expected "a"
fxff : hg said "", expected "a"
fxfx : hg said "a", expected ""
fxf- : agree on "a"
fxxf : agree on "a"
fxxx : agree on ""
fxx- : agree on "a"
fx-f : hg said "", expected "a"
fx-x : hg said "", expected "a"
fx-- : hg said "", expected "a"
f-fx : agree on "a"
f-xf : agree on "a"
f-xx : hg said "", expected "a"
f-x- : agree on "a"
f--x : agree on "a"
-ffx : agree on "a"
-fxf C: agree on "a"
-fxx C: hg said "", expected "a"
-fx- C: agree on "a"
-f-x : hg said "", expected "a"
--fx : agree on "a"
#endif
Files modified or cleanly merged, with no greatest common ancestors:
$ hg init repo; cd repo
$ touch a0 b0; hg commit -qAm 0
$ hg up -qr null; touch a1 b1; hg commit -qAm 1
$ hg merge -qr 0; rm b*; hg commit -qAm 2
$ hg log -r . -T '{files}\n'
b0 b1
$ cd ../
$ rm -rf repo
A few cases of criss-cross merges involving deletions (listing all
such merges is probably too much). Both gcas contain $files, so we
expect the final merge to behave like a merge with a single gca
containing $files.
$ hg init repo; cd repo
$ files="c1 u1 c2 u2"
$ touch $files; hg commit -qAm '0 root'
$ for f in $files; do echo f > $f; done; hg commit -qAm '1 gca1'
$ hg up -qr0; hg revert -qr 1 --all; hg commit -qAm '2 gca2'
$ hg up -qr 1; hg merge -qr 2; rm *1; hg commit -qAm '3 p1'
$ hg up -qr 2; hg merge -qr 1; rm *2; hg commit -qAm '4 p2'
$ hg merge -qr 3; echo f > u1; echo f > u2; rm -f c1 c2
$ hg commit -qAm '5 merge with two gcas'
$ hg log -r . -T '{files}\n' # expecting u1 u2
c1
$ cd ../
$ rm -rf repo