diff mercurial/patch.py @ 22296:650b5b6e75ed

convert: use None value for missing files instead of overloading IOError

The internal API used IOError to indicate that a file should be marked as
removed.

There is some correlation between IOError (especially with ENOENT) and files
that should be removed, but using IOErrors to represent file removal internally
required some hacks.

Instead, use the value None to indicate that the file not is present.

Before, spurious IO errors could cause commits that silently removed files.
They will now be reported like all other IO errors so the root cause can be
fixed.

--- a/mercurial/patch.py	Wed Aug 27 12:30:28 2014 +0200
+++ b/mercurial/patch.py	Tue Aug 26 22:03:32 2014 +0200
@@ -382,7 +382,7 @@
 
     def getfile(self, fname):
         """Return target file data and flags as a (data, (islink,
-        isexec)) tuple.
+        isexec)) tuple. Data is None if file is missing/deleted.
         """
         raise NotImplementedError
 
@@ -426,7 +426,12 @@
         except OSError, e:
             if e.errno != errno.ENOENT:
                 raise
-        return (self.opener.read(fname), (False, isexec))
+        try:
+            return (self.opener.read(fname), (False, isexec))
+        except IOError, e:
+            if e.errno != errno.ENOENT:
+                raise
+            return None, None
 
     def setfile(self, fname, data, mode, copysource):
         islink, isexec = mode
@@ -528,7 +533,7 @@
         if fname in self.data:
             return self.data[fname]
         if not self.opener or fname not in self.files:
-            raise IOError
+            return None, None, None
         fn, mode, copied = self.files[fname]
         return self.opener.read(fn), mode, copied
 
@@ -554,7 +559,7 @@
         try:
             fctx = self.ctx[fname]
         except error.LookupError:
-            raise IOError
+            return None, None
         flags = fctx.flags()
         return fctx.data(), ('l' in flags, 'x' in flags)
 
@@ -597,13 +602,12 @@
         self.copysource = gp.oldpath
         self.create = gp.op in ('ADD', 'COPY', 'RENAME')
         self.remove = gp.op == 'DELETE'
-        try:
-            if self.copysource is None:
-                data, mode = backend.getfile(self.fname)
-                self.exists = True
-            else:
-                data, mode = store.getfile(self.copysource)[:2]
-                self.exists = backend.exists(self.fname)
+        if self.copysource is None:
+            data, mode = backend.getfile(self.fname)
+        else:
+            data, mode = store.getfile(self.copysource)[:2]
+        if data is not None:
+            self.exists = self.copysource is None or backend.exists(self.fname)
             self.missing = False
             if data:
                 self.lines = mdiff.splitnewlines(data)
@@ -622,7 +626,7 @@
                             l = l[:-2] + '\n'
                         nlines.append(l)
                     self.lines = nlines
-        except IOError:
+        else:
             if self.create:
                 self.missing = False
             if self.mode is None:
@@ -1380,6 +1384,8 @@
                 data, mode = None, None
                 if gp.op in ('RENAME', 'COPY'):
                     data, mode = store.getfile(gp.oldpath)[:2]
+                    # FIXME: failing getfile has never been handled here
+                    assert data is not None
                 if gp.mode:
                     mode = gp.mode
                     if gp.op == 'ADD':
@@ -1404,15 +1410,13 @@
         elif state == 'git':
             for gp in values:
                 path = pstrip(gp.oldpath)
-                try:
-                    data, mode = backend.getfile(path)
-                except IOError, e:
-                    if e.errno != errno.ENOENT:
-                        raise
+                data, mode = backend.getfile(path)
+                if data is None:
                     # The error ignored here will trigger a getfile()
                     # error in a place more appropriate for error
                     # handling, and will not interrupt the patching
                     # process.
+                    pass
                 else:
                     store.setfile(path, data, mode)
         else: