git still supports a variant of that (if you set the "ident" flag in gitattributes), though it uses the blob hash of that file, not the commit hash. But in gen

git still supports a variant of that (if you set the "ident" flag in gitattributes), though it uses the blob hash of that file, not the commit hash. But in general, git doesn't look kindly on gratuitous modifications to source files. Those modifications can never occur in the actual files in the repository, since you can't hash something that contains its own hash (unless the hash is broken). And having the file in the working directory not match the file in the repository makes life difficult in various ways (diffs, etc).