CodeQL-inspired fixes #1891
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CodeQL-inspired fixes #1891
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The difference of two unsigned integers is defined to be unsigned, and therefore it is misleading to check whether it is greater than zero. Let's instead avoid the subtraction altogether. Pointed out by CodeQL's rule with the ID `cpp/unsigned-difference-expression-compared-zero`. Signed-off-by: Johannes Schindelin <[email protected]>
As pointed out by CodeQL, it is a potentially dangerous practice to store local variables' addresses in non-local structs. Yet this is exactly what happens with the `acked_commits` attribute that is used in `cmd_fetch()`: The pointer to a local variable is assigned to it. Now, it is Git's convention that `cmd_*()` functions are essentially only returning just before exiting the process, therefore there is little danger that this attribute is used after the code flow returns from that function. However, code in `cmd_*()` function is often so useful that it gets lifted into a library function, at which point this issue could become a real problem. Let's make sure to clear the `acked_commits` attribute out after it was used, and before the function returns (at which point the address would go stale). Signed-off-by: Johannes Schindelin <[email protected]>
We do need a context to write the commit graph, but that context is only needed during the life time of `commit_graph_write()`, therefore it can easily be a stack variable. This also helps CodeQL recognize that it is safe to assign the address of other local variables to the context's fields. Signed-off-by: Johannes Schindelin <[email protected]>
While 3145ea9 (upload-pack: introduce fetch server command, 2018-03-15) added support for the `fetch` command, from the server's point of view it is an upload, and hence the `enum` should really be called `upload_state` instead of `fetch_state`. Likewise, rename its values. This also helps unconfuse CodeQL which would otherwise be at sixes or sevens about having _two_ non-local definitions of the same `enum` with the same values. Signed-off-by: Johannes Schindelin <[email protected]>
One thing that might be non-obvious to readers (or to analyzers like CodeQL) is that the function essentially does nothing when the Git index is empty, and in particular that it does not look at the value of `len_eq_last` (which would be uninitialized at that point). Let's make this much easier to understand, by returning early if the Git index is empty, and by avoiding empty `else` blocks. This commit changes indentation and is hence best viewed using `--ignore-space-change`. Signed-off-by: Johannes Schindelin <[email protected]>
As pointed out by CodeQL, `branch_get()` may return `NULL`, in which
case `branch_has_merge_config()` would return early, but we can even
avoid enumerating the refs prefixes in that case, saving even more CPU
cycles.
Technically, we should enclose these two statements in an `if (branch)
{...}` block, but the indentation is already quite deep, therefore I
refrained from doing that.
Signed-off-by: Johannes Schindelin <[email protected]>
While `if (i < 0) ... else if (i >= 0) ...` is technically equivalent to `if (i < 0) ... else ...`, the latter is vastly easier to read because it avoids writing out a condition that is unnecessary. Let's drop such unnecessary conditions. Pointed out by CodeQL. Signed-off-by: Johannes Schindelin <[email protected]>
CodeQL reports empty `if` blocks that only contain a comment as "futile conditional". The comment talks about potential plans to turn this into a warning, but that seems not to have been necessary. Replace the entire construct with a concise comment. Signed-off-by: Johannes Schindelin <[email protected]>
The code is a bit too hard to reason about to fully assess whether the `fill_commit_graph_info()` function is called at all after `write_commit_graph()` returns (and hence the stack variable `topo_levels` goes out of context). Let's simply make sure that the stack address is no longer used at that stage, thereby making the code quite a bit easier to reason about. Signed-off-by: Johannes Schindelin <[email protected]>
In c429bed (bundle-uri: store fetch.bundleCreationToken, 2023-01-31) code was introduced that assumes that an `sscanf()` call leaves its output variables unchanged unless the return value indicates success. However, the POSIX documentation makes no such guarantee: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sscanf.html So let's make sure that the output variable `maxCreationToken` is always well-defined. Signed-off-by: Johannes Schindelin <[email protected]>
In 3e81bcc (sequencer: factor out todo command name parsing, 2019-06-27), a `return` statement was introduced that basically was a long sequence of conditions, combined with `&&`, except for the last condition which is not really a condition but an assignment. The point of this construct was to return 1 (i.e. `true`) from the function if all of those conditions held true, and also assign the `bol` pointer to the end of the parsed command. Some static analyzers are really unhappy about such constructs. And human readers are at least puzzled, if not confused, by seeing a single `=` inside a chain of conditions where they would have expected to see `==` instead and, based on experience, immediately suspect a typo. Let's help all of this by turning this into the more verbose, more readable form of an `if` construct that both assigns the pointer as well as returns 1 if all of the conditions hold true. Signed-off-by: Johannes Schindelin <[email protected]>
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CodeQL pointed out a couple of issues, which are addressed in this patch series.