fix(Sheets): .gitignore in cheatpath (#699)

Fix an issue whereby `cheat` would crash if a cheatpath contained a file
that began with `.git`, like `.gitignore`.
This commit is contained in:
Christopher Allen Lane 2022-08-27 20:57:07 -04:00
parent db3d7e53a4
commit ede2d2dbaa

View File

@ -37,16 +37,53 @@ func isGitDir(path string) (bool, error) {
See: https://github.com/cheat/cheat/issues/694
Accounting for all of the above, we are now searching for the presence
of a `.git` literal string in the cheatsheet file path. If it is not
found, we continue to walk the directory, as before.
The next attempt at solving this was to search for a `.git` literal
string in the cheatsheet file path. If a match was not found, we would
continue to walk the directory, as before.
If it *is* found, we determine if `.git` refers to a file or directory,
and only stop walking the path in the latter case.
If a match *was* found, we determined whether `.git` referred to a file
or directory, and would only stop walking the path in the latter case.
This, however, caused crashes if a cheatpath contained a `.gitignore`
file. (Presumably, a crash would likewise occur on the presence of
`.gitattributes`, `.gitmodules`, etc.)
See: https://github.com/cheat/cheat/issues/699
Accounting for all of the above (hopefully?), the current solution is
not to search for `.git`, but `.git/` (including the directory
separator), and then only ceasing to walk the directory on a match.
To summarize, this code must account for the following possibilities:
1. A cheatpath is not a repository
2. A cheatpath is a repository
3. A cheatpath is a repository, and contains a `.git*` file
4. A cheatpath is a submodule
Care must be taken to support the above on both Unix and Windows
systems, which have different directory separators and line-endings.
There is a lot of nuance to all of this, and it would be worthwhile to
do two things to stop writing bugs here:
1. Build integration tests around all of this
2. Discard string-matching solutions entirely, and use `go-git` instead
NB: A reasonable smoke-test for ensuring that skipping is being applied
correctly is to run the following command:
make && strace ./dist/cheat -l | wc -l
That check should be run twice: once normally, and once after
commenting out the "skip" check in `sheets.Load`.
The specific line counts don't matter; what matters is that the number
of syscalls should be significantly lower with the skip check enabled.
*/
// determine if the literal string `.git` appears within `path`
pos := strings.Index(path, ".git")
pos := strings.Index(path, fmt.Sprintf(".git%s", string(os.PathSeparator)))
// if it does not, we know for certain that we are not within a `.git`
// directory.
@ -61,7 +98,7 @@ func isGitDir(path string) (bool, error) {
// See: https://github.com/cheat/cheat/issues/694
// truncate `path` to the occurrence of `.git`
f, err := os.Stat(path[:pos+4])
f, err := os.Stat(path[:pos+5])
if err != nil {
return false, fmt.Errorf("failed to stat path %s: %v", path, err)
}