[PATCH 9 of 9 V2] merge: store cases when a file is absent post merge in commitinfo

[Pulkit Goyal]

# HG changeset patch
# User Pulkit Goyal <7895pulkit at gmail.com>
# Date 1598263534 -19800
#      Mon Aug 24 15:35:34 2020 +0530
# Node ID 7331100f93338574bf3e289fef3e622fd16859a5
# Parent  2194dc931f08e7682f75054c7bb1754ea43d504a
# EXP-Topic merge-newnode
merge: store cases when a file is absent post merge in commitinfo

Some merges can result in file being absent form working directory. This can be
one of file was kept deleted or file was removed by merge code.

User might revert the file back before committing. In such cases we will like to
have better handling and create new filenodes.

We store this info in mergestate as commitinfo so that we can use it while
committing to create new filenode if required.

Differential Revision: https://phab.mercurial-scm.org/D9003

diff --git a/mercurial/merge.py b/mercurial/merge.py
--- a/mercurial/merge.py
+++ b/mercurial/merge.py
@@ -923,6 +923,15 @@ def manifestmerge(
                     mresult.addfile(
                         f, mergestatemod.ACTION_REMOVE, None, b'other deleted',
                     )
+                    if branchmerge:
+                        # the file must be absent after merging,
+                        # howeber the user might make
+                        # the file reappear using revert and if they does,
+                        # we force create a new node
+                        mresult.addcommitinfo(
+                            f, b'MERGE_REMOVAL_CANDIDATE', b'yes'
+                        )
+
             else:  # file not in ancestor, not in remote
                 mresult.addfile(
                     f,
@@ -1033,6 +1042,12 @@ def manifestmerge(
                     None,
                     b'local not present, remote unchanged',
                 )
+                if branchmerge:
+                    # the file must be absent after merging
+                    # however the user might make
+                    # the file reappear using revert and if they does,
+                    # we force create a new node
+                    mresult.addcommitinfo(f, b'MERGE_REMOVAL_CANDIDATE', b'yes')
 
     if repo.ui.configbool(b'experimental', b'merge.checkpathconflicts'):
         # If we are merging, look for path conflicts.
diff --git a/tests/test-merge-criss-cross.t b/tests/test-merge-criss-cross.t
--- a/tests/test-merge-criss-cross.t
+++ b/tests/test-merge-criss-cross.t
@@ -682,7 +682,9 @@ BROKEN: this should result in conflict
   extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 #else
   $ hg debugmergestate
-  no merge state found
+  local (working copy): adfd88e5d7d3d3e22bdd26512991ee64d59c1d8f
+  other (merge rev): e9b7081317232edce73f7ad5ae0b7807ff5c326a
+  extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 #endif
 
 (merging a deletion with keeping → conflict)
@@ -697,7 +699,9 @@ BROKEN: this should result in conflict
   $ ls -1
   other-file
   $ hg debugmergestate
-  no merge state found
+  local (working copy): adfd88e5d7d3d3e22bdd26512991ee64d59c1d8f
+  other (merge rev): 5e3eccec60d88f94a7ba57c351f32cb24c15fe0c
+  extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 
 (merging two deletion together → no conflict)
 
@@ -730,7 +734,9 @@ BROKEN: this should result in conflict
   extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 #else
   $ hg debugmergestate
-  no merge state found
+  local (working copy): a4e0e44229dc130be2915b92c957c093f8c7ee3e
+  other (merge rev): e9b7081317232edce73f7ad5ae0b7807ff5c326a
+  extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 #endif
 
 (merging a deletion with keeping → conflict)
@@ -745,7 +751,9 @@ BROKEN: this should result in conflict
   $ ls -1
   other-file
   $ hg debugmergestate
-  no merge state found
+  local (working copy): a4e0e44229dc130be2915b92c957c093f8c7ee3e
+  other (merge rev): 5e3eccec60d88f94a7ba57c351f32cb24c15fe0c
+  extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 
 (merging two "keeping" together → no conflict)
 
@@ -795,7 +803,9 @@ BROKEN: this should result in conflict
   other-file
   the-file
   $ hg debugmergestate
-  no merge state found
+  local (working copy): 5e3eccec60d88f94a7ba57c351f32cb24c15fe0c
+  other (merge rev): a4e0e44229dc130be2915b92c957c093f8c7ee3e
+  extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 
 (merging two "keeping" together → no conflict)
 
@@ -843,5 +853,7 @@ BROKEN: this should result in conflict
   extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 #else
   $ hg debugmergestate
-  no merge state found
+  local (working copy): e9b7081317232edce73f7ad5ae0b7807ff5c326a
+  other (merge rev): a4e0e44229dc130be2915b92c957c093f8c7ee3e
+  extra: the-file (MERGE_REMOVAL_CANDIDATE = yes)
 #endif