git/notes.c, branch v2.32.2

hash: provide per-algorithm null OIDs

2021-04-27T07:31:39Z

Up until recently, object IDs did not have an algorithm member, only a hash. Consequently, it was possible to share one null (all-zeros) object ID among all hash algorithms. Now that we're going to be handling objects from multiple hash algorithms, it's important to make sure that all object IDs have a correct algorithm field. Introduce a per-algorithm null OID, and add it to struct hash_algo. Introduce a wrapper function as well, and use it everywhere we used to use the null_oid constant. Signed-off-by: brian m. carlson Signed-off-by: Junio C Hamano

hash: set, copy, and use algo field in struct object_id

2021-04-27T07:31:38Z

Now that struct object_id has an algorithm field, we should populate it. This will allow us to handle object IDs in any supported algorithm and distinguish between them. Ensure that the field is written whenever we write an object ID by storing it explicitly every time we write an object. Set values for the empty blob and tree values as well. In addition, use the algorithm field to compare object IDs. Note that because we zero-initialize struct object_id in many places throughout the codebase, we default to the default algorithm in cases where the algorithm field is zero rather than explicitly initialize all of those locations. This leads to a branch on every comparison, but the alternative is to compare the entire buffer each time and padding the buffer for SHA-1. That alternative ranges up to 3.9% worse than this approach on the perf t0001, t1450, and t1451. Signed-off-by: brian m. carlson Signed-off-by: Junio C Hamano

Always use oidread to read into struct object_id

2021-04-27T07:31:38Z

In the future, we'll want oidread to automatically set the hash algorithm member for an object ID we read into it, so ensure we use oidread instead of hashcpy everywhere we're copying a hash value into a struct object_id. Signed-off-by: brian m. carlson Signed-off-by: Junio C Hamano

use CALLOC_ARRAY

2021-03-14T00:00:09Z

Add and apply a semantic patch for converting code that open-codes CALLOC_ARRAY to use it instead. It shortens the code and infers the element size automatically. Signed-off-by: René Scharfe Signed-off-by: Junio C Hamano

Merge branch 'na/notes-displayref-is-not-boolean'

2020-11-30T22:49:44Z

Config parser fix for "git notes". * na/notes-displayref-is-not-boolean: t3301: test proper exit response to no-value notes.displayRef. notes.c: fix a segfault in notes_display_config()

notes.c: fix a segfault in notes_display_config()

2020-11-23T18:42:22Z

If notes.displayRef is configured with no value[1], control should be returned to the caller when notes.c:notes_display_config() checks if 'v' is NULL. Otherwise, both git log --notes and git diff-tree --notes will subsequently segfault when refs.h:has_glob_specials() calls strpbrk() with a NULL first argument. [1] Examples: .git/config: [notes] displayRef $ git -c notes.displayRef [...] Signed-off-by: Nate Avers Signed-off-by: Junio C Hamano

Merge branch 'rs/strbuf-insertstr'

2020-02-17T21:22:17Z

Code clean-up. * rs/strbuf-insertstr: mailinfo: don't insert header prefix for handle_content_type() strbuf: add and use strbuf_insertstr()

Merge branch 'jh/notes-fanout-fix'

2020-02-14T20:54:23Z

The code to automatically shrink the fan-out in the notes tree had an off-by-one bug, which has been killed. * jh/notes-fanout-fix: notes.c: fix off-by-one error when decreasing notes fanout t3305: check notes fanout more carefully and robustly

strbuf: add and use strbuf_insertstr()

2020-02-10T17:04:45Z

Add a function for inserting a C string into a strbuf. Use it throughout the source to get rid of magic string length constants and explicit strlen() calls. Like strbuf_addstr(), implement it as an inline function to avoid the implicit strlen() calls to cause runtime overhead. Helped-by: Taylor Blau Helped-by: Eric Sunshine Signed-off-by: René Scharfe Signed-off-by: Junio C Hamano

notes.c: fix off-by-one error when decreasing notes fanout

2020-02-04T20:20:43Z

As noted in the previous commit, the nature of the fanout heuristic in the notes code causes the exact point at which we increase or decrease the notes fanout to vary with the objects being annotated. Since the object ids generated by the test environment are deterministic (by design), the notes generated and tested by t3305 are always the same, and we therefore happen to see the same fanout behavior from one run to the next. Coincidentally, if we were to change the test environment slightly (say by making a test commit on an unrelated branch before we start the t3305 test proper), we not only see the fanout switch happen at different points, we also manage to trigger a _bug_ in the notes code where the fanout 1 -> 0 switch is not applied uniformly across the notes tree, but instead yields a notes tree like this: ... bdeafb301e44b0e4db0f738a2d2a7beefdb70b70 bff2d39b4f7122bd4c5caee3de353a774d1e632a d3/8ec8f851adf470131178085bfbaab4b12ad2a7 e0b173960431a3e692ae929736df3c9b73a11d5b eb3c3aede523d729990ac25c62a93eb47c21e2e3 ... The bug occurs when we are writing out a notes tree with a newly decreased fanout, and the notes tree contains unexpanded subtrees that should be consolidated into the parent tree as a consequence of the decreased fanout): Subtrees that happen to sit at an _even_ level in the internal notes 16-tree structure (in other words: subtrees whose path - "d3" in the example above - is unique in the first nibble - i.e. there are no other note paths that start with "d") are _not_ unpacked as part of the tree writeout. This error will repeat itself in subsequent note trees until the subtree is forced to be unpacked. In t3305 this only happens when the d38ec8f8 note is itself removed from the tree. The error is not severe (no information is lost, and the notes code is able to read/decode this tree and manipulate it correctly), but this is nonetheless a bug in the current implementation that should be fixed. That said, fixing the off-by-one error is not without complications: We must take into account that the load_subtree() call from for_each_note_helper() (that is now done to correctly unpack the subtree while we're writing out the notes tree) may end up inserting unpacked non-notes into the linked list of non_note entries held by the struct notes_tree. Since we are in the process of writing out the notes tree, this linked list is currently in the process of being traversed by write_each_non_note_until(). The unpacked non-notes are necessarily inserted between the last non-note we wrote out, and the next non-note to be written. Hence, we cannot simply hold the next_non_note to write in struct write_each_note_data (as we would then silently skip these newly inserted notes), but must instead always follow the ->next pointer from the last non-note we wrote. (This part was caught by an existing test in t3304.) Cc: Johannes Schindelin Cc: Brian M. Carlson Signed-off-by: Johan Herland Signed-off-by: Junio C Hamano