Mercurial > hg
changeset 31761:b044c339c06d
verify: document corner cases
It seems a good idea to list all kinds of "surprises" and expected behavior
to make the upcoming changes easier to understand.
Note: the comment added does not reflect the actual behavior of the current
code.
| author | Jun Wu <quark@fb.com> |
|---|---|
| date | Wed, 29 Mar 2017 14:45:01 -0700 |
| parents | 04ec317b8128 |
| children | dff03f68ef11 |
| files | mercurial/verify.py |
| diffstat | 1 files changed, 47 insertions(+), 1 deletions(-) [+] |
line wrap: on
line diff
--- a/mercurial/verify.py Wed Mar 29 22:26:16 2017 +0200 +++ b/mercurial/verify.py Wed Mar 29 14:45:01 2017 -0700 @@ -379,7 +379,53 @@ else: del filenodes[f][n] - # verify contents + # Verify contents. 4 cases to care about: + # + # common: the most common case + # rename: with a rename + # meta: file content starts with b'\1\n', the metadata + # header defined in filelog.py, but without a rename + # ext: content stored externally + # + # More formally, their differences are shown below: + # + # | common | rename | meta | ext + # ------------------------------------------------------- + # flags() | 0 | 0 | 0 | not 0 + # renamed() | False | True | False | ? + # rawtext[0:2]=='\1\n'| False | True | True | ? + # + # "rawtext" means the raw text stored in revlog data, which + # could be retrieved by "revision(rev, raw=True)". "text" + # mentioned below is "revision(rev, raw=False)". + # + # There are 3 different lengths stored physically: + # 1. L1: rawsize, stored in revlog index + # 2. L2: len(rawtext), stored in revlog data + # 3. L3: len(text), stored in revlog data if flags==0, or + # possibly somewhere else if flags!=0 + # + # L1 should be equal to L2. L3 could be different from them. + # "text" may or may not affect commit hash depending on flag + # processors (see revlog.addflagprocessor). + # + # | common | rename | meta | ext + # ------------------------------------------------- + # rawsize() | L1 | L1 | L1 | L1 + # size() | L1 | L2-LM | L1(*) | L1 (?) + # len(rawtext) | L2 | L2 | L2 | L2 + # len(text) | L2 | L2 | L2 | L3 + # len(read()) | L2 | L2-LM | L2-LM | L3 (?) + # + # LM: length of metadata, depending on rawtext + # (*): not ideal, see comment in filelog.size + # (?): could be "- len(meta)" if the resolved content has + # rename metadata + # + # Checks needed to be done: + # 1. length check: L1 == L2, in all cases. + # 2. hash check: depending on flag processor, we may need to + # use either "text" (external), or "rawtext" (in revlog). try: l = len(fl.read(n)) rp = fl.renamed(n)