Mercurial > hg
comparison mercurial/copies.py @ 42227:d1c2688eda80
copies: document cases in _chain()
Differential Revision: https://phab.mercurial-scm.org/D6274
author | Martin von Zweigbergk <martinvonz@google.com> |
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date | Wed, 17 Apr 2019 23:10:14 -0700 |
parents | a6be3af3a397 |
children | df7ad90edbd4 |
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42226:a6be3af3a397 | 42227:d1c2688eda80 |
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106 # back far enough unless we also look at the a and b as candidates. | 106 # back far enough unless we also look at the a and b as candidates. |
107 # This only occurs when a is a descendent of b or visa-versa. | 107 # This only occurs when a is a descendent of b or visa-versa. |
108 return min(limit, a, b) | 108 return min(limit, a, b) |
109 | 109 |
110 def _chain(src, dst, a, b): | 110 def _chain(src, dst, a, b): |
111 """chain two sets of copies a->b""" | 111 """chain two sets of copies 'a' and 'b'""" |
112 | |
113 # When chaining copies in 'a' (from 'src' via some other commit 'mid') with | |
114 # copies in 'b' (from 'mid' to 'dst'), we can get the different cases in the | |
115 # following table (not including trivial cases). For example, case 2 is | |
116 # where a file existed in 'src' and remained under that name in 'mid' and | |
117 # then was renamed between 'mid' and 'dst'. | |
118 # | |
119 # case src mid dst result | |
120 # 1 x y - - | |
121 # 2 x y y x->y | |
122 # 3 x y x - | |
123 # 4 x y z x->z | |
124 # 5 - x y - | |
125 # 6 x x y x->y | |
126 | |
127 # Initialize result ('t') from 'a'. This catches cases 1 & 2. We'll remove | |
128 # case 1 later. We'll also catch cases 3 & 4 here. Case 4 will be | |
129 # overwritten later, and case 3 will be removed later. | |
112 t = a.copy() | 130 t = a.copy() |
113 for k, v in b.iteritems(): | 131 for k, v in b.iteritems(): |
114 if v in t: | 132 if v in t: |
115 # found a chain | 133 # found a chain, i.e. cases 3 & 4. |
116 if t[v] != k: | 134 if t[v] != k: |
117 # file wasn't renamed back to itself | 135 # file wasn't renamed back to itself (i.e. case 4, not 3) |
118 t[k] = t[v] | 136 t[k] = t[v] |
119 if v not in dst: | 137 if v not in dst: |
120 # chain was a rename, not a copy | 138 # chain was a rename, not a copy |
139 # this deletes the copy for 'y' in case 4 | |
121 del t[v] | 140 del t[v] |
122 if v in src: | 141 if v in src: |
123 # file is a copy of an existing file | 142 # file is a copy of an existing file, i.e. case 6. |
124 t[k] = v | 143 t[k] = v |
125 | 144 |
126 for k, v in list(t.items()): | 145 for k, v in list(t.items()): |
127 # remove criss-crossed copies | 146 # remove criss-crossed copies, i.e. case 3 |
128 if k in src and v in dst: | 147 if k in src and v in dst: |
129 del t[k] | 148 del t[k] |
130 # remove copies to files that were then removed | 149 # remove copies to files that were then removed, i.e. case 1 |
150 # and file 'y' in cases 3 & 4 (in case of rename) | |
131 elif k not in dst: | 151 elif k not in dst: |
132 del t[k] | 152 del t[k] |
133 | 153 |
134 return t | 154 return t |
135 | 155 |