src/patch_parse.c


Log

Author Commit Date CI Message
Patrick Steinhardt de7659cc 2019-11-10T18:44:56 patch_parse: use paths from "---"/"+++" lines for binary patches For some patches, it is not possible to derive the old and new file paths from the patch header's first line, most importantly when they contain spaces. In such a case, we derive both paths from the "---" and "+++" lines, which allow for non-ambiguous parsing. We fail to use these paths when parsing binary patches without data, though, as we always expect the header paths to be filled in. Fix this by using the "---"/"+++" paths by default and only fall back to header paths if they aren't set. If neither of those paths are set, we just return an error. Add two tests to verify this behaviour, one of which would have previously caused a segfault.
Patrick Steinhardt de543e29 2019-11-05T22:44:27 patch_parse: fix segfault when header path contains whitespace only When parsing header paths from a patch, we reject any patches with empty paths as malformed patches. We perform the check whether a path is empty before sanitizing it, though, which may lead to a path becoming empty after the check, e.g. if we have trimmed whitespace. This may lead to a segfault later when any part of our patching logic actually references such a path, which may then be a `NULL` pointer. Fix the issue by performing the check after sanitizing. Add tests to catch the issue as they would have produced a segfault previosuly.
Patrick Steinhardt 37141ff7 2019-10-21T18:56:59 patch_parse: detect overflow when calculating old/new line position When the patch contains lines close to INT_MAX, then it may happen that we end up with an integer overflow when calculating the line of the current diff hunk. Reject such patches as unreasonable to avoid the integer overflow. As the calculation is performed on integers, we introduce two new helpers `git__add_int_overflow` and `git__sub_int_overflow` that perform the integer overflow check in a generic way.
Patrick Steinhardt 468e3ddc 2019-10-19T16:48:11 patch_parse: fix out-of-bounds read with No-NL lines We've got two locations where we copy lines into the patch. The first one is when copying normal " ", "-" or "+" lines, while the second location gets executed when we copy "\ No newline at end of file" lines. While the first one correctly uses `git__strndup` to copy only until the newline, the other one doesn't. Thus, if the line occurs at the end of the patch and if there is no terminating NUL character, then it may result in an out-of-bounds read. Fix the issue by using `git__strndup`, as was already done in the other location. Furthermore, add allocation checks to both locations to detect out-of-memory situations.
Patrick Steinhardt 6c6c15e9 2019-10-19T15:52:35 patch_parse: reject empty path names When parsing patch headers, we currently accept empty path names just fine, e.g. a line "--- \n" would be parsed as the empty filename. This is not a valid patch format and may cause `NULL` pointer accesses at a later place as `git_buf_detach` will return `NULL` in that case. Reject such patches as malformed with a nice error message.
Patrick Steinhardt 223e7e43 2019-10-19T15:42:54 patch_parse: reject patches with multiple old/new paths It's currently possible to have patches with multiple old path name headers. As we didn't check for this case, this resulted in a memory leak when overwriting the old old path with the new old path because we simply discarded the old pointer. Instead of fixing this by free'ing the old pointer, we should reject such patches altogether. It doesn't make any sense for the "---" or "+++" markers to occur multiple times within a patch n the first place. This also implicitly fixes the memory leak.
Denis Laxalde 11de594f 2019-10-16T22:11:33 patch_parse: handle patches without extended headers Extended header lines (especially the "index <hash>..<hash> <mode>") are not required by "git apply" so it import patches. So we allow the from-file/to-file lines (--- a/file\n+++ b/file) to directly follow the git diff header. This fixes #5267.
Denis Laxalde b61810bf 2019-09-28T15:52:25 patch_parse: handle patches with new empty files Patches containing additions of empty files will not contain diff data but will end with the index header line followed by the terminating sequence "-- ". We follow the same logic as in cc4c44a and allow "-- " to immediately follow the index header.
Patrick Steinhardt 27b8b31e 2019-08-01T11:57:03 parse: remove use of variadic macros which are not C89 compliant The macro `git_parse_error` is implemented in a variadic way so that it's possible to pass printf-style parameters. Unfortunately, variadic macros are not defined by C89 and thus we cannot use that functionality. But as we have implemented `git_error_vset` in the previous commit, we can now just use that instead. Convert `git_parse_error` to a variadic function and use `git_error_vset` to fix the compliance violation. While at it, move the function to "patch_parse.c".
Patrick Steinhardt a613832e 2019-07-20T18:49:48 patch_parse: fix segfault due to line containing static contents With commit dedf70ad2 (patch_parse: do not depend on parsed buffer's lifetime, 2019-07-05), all lines of the patch are allocated with `strdup` to make lifetime of the parsed patch independent of the buffer that is currently being parsed. In patch b08932824 (patch_parse: ensure valid patch output with EOFNL, 2019-07-11), we introduced another code location where we add lines to the parsed patch. But as that one was implemented via a separate pull request, it wasn't converted to use `strdup`, as well. As a consequence, we generate a segfault when trying to deallocate the potentially static buffer that's now in some of the lines. Use `git__strdup` to fix the issue.
Edward Thomson fd7a384b 2019-07-20T11:24:37 Merge pull request #5159 from pks-t/pks/patch-parse-old-missing-nl patch_parse: handle missing newline indicator in old file
Erik Aigner b0893282 2019-07-11T12:12:04 patch_parse: ensure valid patch output with EOFNL
Patrick Steinhardt 3f855fe8 2019-07-05T11:06:33 patch_parse: handle missing newline indicator in old file When either the old or new file contents have no newline at the end of the file, then git-diff(1) will print out a "\ No newline at end of file" indicator. While we do correctly handle this in the case where the new file has this indcator, we fail to parse patches where the old file is missing a newline at EOF. Fix this bug by handling and missing newline indicators in the old file. Add tests to verify that we can parse such files.
Patrick Steinhardt dedf70ad 2019-07-05T09:35:43 patch_parse: do not depend on parsed buffer's lifetime When parsing a patch from a buffer, we let the patch lines point into the original buffer. While this is efficient use of resources, this also ties the lifetime of the parsed patch to the parsed buffer. As this behaviour is not documented anywhere in our API it is very surprising to its users. Untie the lifetime by duplicating the lines into the parsed patch. Add a test that verifies that lifetimes are indeed independent of each other.
Edward Thomson f1d73189 2019-05-20T07:02:50 patch: use size_t for size when parsing
Drew DeVault 30c06b60 2019-03-22T23:56:10 patch_parse.c: Handle CRLF in parse_header_start
Patrick Steinhardt b3497344 2019-03-29T12:15:20 patch_parse: fix parsing addition/deletion of file with space The diff header format is a strange beast in that it is inherently unparseable in an unambiguous way. While parsing a/file.txt b/file.txt is obvious and trivially doable, parsing a diff header of a/file b/file ab.txt b/file b/file ab.txt is not (but in fact valid and created by git.git). Due to that, we have relaxed our diff header parser in commit 80226b5f6 (patch_parse: allow parsing ambiguous patch headers, 2017-09-22), so that we started to bail out when seeing diff headers with spaces in their file names. Instead, we try to use the "---" and "+++" lines, which are unambiguous. In some cases, though, we neither have a useable file name from the header nor from the "---" or "+++" lines. This is the case when we have a deletion or addition of a file with spaces: the header is unparseable and the other lines will simply show "/dev/null". This trips our parsing logic when we try to extract the prefix (the "a/" part) that is being used in the path line, where we unconditionally try to dereference a NULL pointer in such a scenario. We can fix this by simply not trying to parse the prefix in cases where we have no useable path name. That'd leave the parsed patch without either `old_prefix` or `new_prefix` populated. But in fact such cases are already handled by users of the patch object, which simply opt to use the default prefixes in that case.
Patrick Steinhardt 131cd9b1 2019-03-29T11:58:50 patch_parse: improve formatting
Edward Thomson 80c3867b 2019-01-20T19:20:12 patch: explicitly cast down in parse_header_percent Quiet down a warning from MSVC about how we're potentially losing data. This is safe since we've explicitly tested that it's within the range of 0-100.
Edward Thomson f673e232 2018-12-27T13:47:34 git_error: use new names in internal APIs and usage Move to the `git_error` name in the internal API for error-related functions.
Patrick Steinhardt 4b84db6a 2018-11-14T12:33:38 patch_parse: remove unused function `parse_number` The function `parse_number` was replaced by `git_parse_advance_digit` which is provided by the parser interface in commit 252f2eeee (parse: implement and use `git_parse_advance_digit`, 2017-07-14). As there are no remaining callers, remove it.
Etienne Samson f9e28026 2018-06-18T20:37:18 patch_parse: populate line numbers while parsing diffs
Patrick Steinhardt ecf4f33a 2018-02-08T11:14:48 Convert usage of `git_buf_free` to new `git_buf_dispose`
Patrick Steinhardt 06b8a40f 2018-02-16T11:29:46 Explicitly mark fallthrough cases with comments A lot of compilers nowadays generate warnings when there are cases in a switch statement which implicitly fall through to the next case. To avoid this warning, the last line in the case that is falling through can have a comment matching a regular expression, where one possible comment body would be `/* fall through */`. An alternative to the comment would be an explicit attribute like e.g. `[[clang::fallthrough]` or `__attribute__ ((fallthrough))`. But GCC only introduced support for such an attribute recently with GCC 7. Thus, and also because the fallthrough comment is supported by most compilers, we settle for using comments instead. One shortcoming of that method is that compilers are very strict about that. Most interestingly, that comment _really_ has to be the last line. In case a closing brace follows the comment, the heuristic will fail.
Edward Thomson 4110fc84 2017-12-23T23:30:29 Merge pull request #4285 from pks-t/pks/patches-with-whitespace patch_parse: fix parsing unquoted filenames with spaces
Patrick Steinhardt 585b5dac 2017-11-18T15:43:11 refcount: make refcounting conform to aliasing rules Strict aliasing rules dictate that for most data types, you are not allowed to cast them to another data type and then access the casted pointers. While this works just fine for most compilers, technically we end up in undefined behaviour when we hurt that rule. Our current refcounting code makes heavy use of casting and thus violates that rule. While we didn't have any problems with that code, Travis started spitting out a lot of warnings due to a change in their toolchain. In the refcounting case, the code is also easy to fix: as all refcounting-statements are actually macros, we can just access the `rc` field directly instead of casting. There are two outliers in our code where that doesn't work. Both the `git_diff` and `git_patch` structures have specializations for generated and parsed diffs/patches, which directly inherit from them. Because of that, the refcounting code is only part of the base structure and not of the children themselves. We can help that by instead passing their base into `GIT_REFCOUNT_INC`, though.
Patrick Steinhardt 80226b5f 2017-09-22T13:39:05 patch_parse: allow parsing ambiguous patch headers The git patch format allows for having unquoted paths with whitespaces inside. This format becomes ambiguous to parse, e.g. in the following example: diff --git a/file b/with spaces.txt b/file b/with spaces.txt While we cannot parse this in a correct way, we can instead use the "---" and "+++" lines to retrieve the file names, as the path is not followed by anything here but spans the complete remaining line. Because of this, we can simply bail outwhen parsing the "diff --git" header here without an actual error and then proceed to just take the paths from the other headers.
Patrick Steinhardt 3892f70d 2017-09-22T13:26:47 patch_parse: treat complete line after "---"/"+++" as path When parsing the "---" and "+++" line, we stop after the first whitespace inside of the filename. But as files containing whitespaces do not need to be quoted, we should instead use the complete line here. This fixes parsing patches with unquoted paths with whitespaces.
Patrick Steinhardt 7bdfc0a6 2017-07-14T15:33:32 parse: always initialize line pointer Upon initializing the parser context, we do not currently initialize the current line, line length and line number. Do so in order to make the interface easier to use and more obvious for future consumers of the parsing API.
Patrick Steinhardt e72cb769 2017-07-14T14:37:07 parse: implement `git_parse_peek` Some code parts need to inspect the next few bytes without actually consuming it yet, for example to examine what content it has to expect next. Create a new function `git_parse_peek` which returns the next byte without modifying the parsing context and use it at multiple call sites.
Patrick Steinhardt 252f2eee 2017-07-14T13:45:05 parse: implement and use `git_parse_advance_digit` The patch parsing code has multiple recurring patterns where we want to parse an actual number. Create a new function `git_parse_advance_digit` and use it to avoid code duplication.
Patrick Steinhardt 65dcb645 2017-07-14T13:29:29 patch_parse: use git_parse_contains_s Instead of manually checking the parsing context's remaining length and comparing the leading bytes with a specific string, we can simply re-use the function `git_parse_ctx_contains_s`. Do so to avoid code duplication and to further decouple patch parsing from the parsing context's struct members.
Patrick Steinhardt ef1395f3 2017-11-11T15:30:43 parse: extract parse module The `git_patch_parse_ctx` encapsulates both parser state as well as options specific to patch parsing. To advance this state and keep it consistent, we provide a few functions which handle advancing the current position and accessing bytes of the patch contents. In fact, these functions are quite generic and not related to patch-parsing by themselves. Seeing that we have similar logic inside of other modules, it becomes quite enticing to extract this functionality into its own parser module. To do so, we create a new module `parse` with a central struct called `git_parse_ctx`. It encapsulates both the content that is to be parsed as well as its lengths and the current position. `git_patch_parse_ctx` now only contains this `parse_ctx` only, which is then accessed whenever we need to touch the current parser. This is the first step towards re-using this functionality across other modules which require parsing functionality and remove code-duplication.
Patrick Steinhardt cc4c44a9 2017-09-01T09:37:05 patch_parse: fix parsing patches only containing exact renames Patches which contain exact renames only will not contain an actual diff body, but only a list of files that were renamed. Thus, the patch header is immediately followed by the terminating sequence "-- ". We currently do not recognize this character sequence as a possible terminating sequence. Add it and create a test to catch the failure.
Patrick Steinhardt 57bc9dab 2017-07-14T10:57:49 patch_parse: implement state machine for parsing patch headers Our code parsing Git patch headers is rather lax in parsing headers of a Git-style patch. Most notably, we do not care for the exact order in which header lines appear and as such, we may parse patch files which are not really valid after all. Furthermore, the state transitions inside of the parser are not as obvious as they could be, making it harder than required to follow its logic. To improve upon this situation, this patch introduces a real state machine to parse the patches. Instead of simply parsing each line without caring for previous state and the exact ordering, we define a set of states with their allowed transitions. This makes the patch parser more strict in only allowing valid successions of header lines. As the transition table is defined inside of a single structure with the expected line, required state as well as the state that we end up in, all state transitions are immediately obvious from just having a look at this structure. This improves both maintainability and eases reasoning about the patch parser.
Patrick Steinhardt 0c7f49dd 2017-06-30T13:39:01 Make sure to always include "common.h" first Next to including several files, our "common.h" header also declares various macros which are then used throughout the project. As such, we have to make sure to always include this file first in all implementation files. Otherwise, we might encounter problems or even silent behavioural differences due to macros or defines not being defined as they should be. So in fact, our header and implementation files should make sure to always include "common.h" first. This commit does so by establishing a common include pattern. Header files inside of "src" will now always include "common.h" as its first other file, separated by a newline from all the other includes to make it stand out as special. There are two cases for the implementation files. If they do have a matching header file, they will always include this one first, leading to "common.h" being transitively included as first file. If they do not have a matching header file, they instead include "common.h" as first file themselves. This fixes the outlined problems and will become our standard practice for header and source files inside of the "src/" from now on.
Patrick Steinhardt 723bdf48 2017-03-20T09:35:23 patch_parse: check if advancing over header newline succeeds While parsing patch header lines, we iterate over each line and check if the line has trailing garbage. What we do not check though is that the line is actually a line ending with a trailing newline. Fix this by checking the return code of `parse_advance_expected_str`.
Patrick Steinhardt ad5a909c 2017-03-14T09:39:37 patch_parse: fix parsing minimal trailing diff line In a diff, the shortest possible hunk with a modification (that is, no deletion) results from a file with only one line with a single character which is removed. Thus the following hunk @@ -1 +1 @@ -a + is the shortest valid hunk modifying a line. The function parsing the hunk body though assumes that there must always be at least 4 bytes present to make up a valid hunk, which is obviously wrong in this case. The absolute minimum number of bytes required for a modification is actually 2 bytes, that is the "+" and the following newline. Note: if there is no trailing newline, the assumption will not be offended as the diff will have a line "\ No trailing newline" at its end. This patch fixes the issue by lowering the amount of bytes required.
Patrick Steinhardt 613381fc 2016-11-15T13:33:05 patch_parse: fix memory leak
Patrick Steinhardt c77a55a9 2016-11-14T10:05:31 common: use PRIuZ for size_t in `giterr_set` calls
Edward Thomson adedac5a 2016-09-02T02:03:45 diff: treat binary patches with no data special When creating and printing diffs, deal with binary deltas that have binary data specially, versus diffs that have a binary file but lack the actual binary data.
Edward Thomson b859faa6 2016-08-23T23:38:39 Teach `git_patch_from_diff` about parsed diffs Ensure that `git_patch_from_diff` can return the patch for parsed diffs, not just generate a patch for a generated diff.
Edward Thomson 002c8e29 2016-08-03T17:09:41 git_diff_file: move `id_abbrev` Move `id_abbrev` to a more reasonable place where it packs more nicely (before anybody starts using it).
Edward Thomson c065f6a1 2016-07-14T23:04:47 apply: check allocation properly
Edward Thomson 1a79cd95 2016-04-26T01:18:01 patch: show copy information for identical copies When showing copy information because we are duplicating contents, for example, when performing a `diff --find-copies-harder -M100 -B100`, then show copy from/to lines in a patch, and do not show context. Ensure that we can also parse such patches.
Edward Thomson 38a347ea 2016-04-25T17:52:39 patch::parse: handle patches with no hunks Patches may have no hunks when there's no modifications (for example, in a rename). Handle them.
Edward Thomson 853e585f 2016-04-25T16:32:30 patch: zero id and abbrev length for empty files
Edward Thomson 33ae8762 2016-04-25T13:07:18 patch: identify non-binary patches as `NOT_BINARY`
Edward Thomson 7166bb16 2016-04-25T00:35:48 introduce `git_diff_from_buffer` to parse diffs Parse diff files into a `git_diff` structure.
Edward Thomson 94e488a0 2016-04-24T16:14:25 patch: differentiate not found and invalid patches
Edward Thomson 17572f67 2016-04-21T00:04:14 git_patch_parse_ctx: refcount the context
Edward Thomson aa4bfb32 2016-02-07T15:08:16 parse: introduce parse_ctx_contains_s
Edward Thomson 440e3bae 2015-11-21T12:27:03 patch: `git_patch_from_patchfile` -> `git_patch_from_buffer`
Edward Thomson 00e63b36 2015-11-21T12:37:01 patch: provide static string `advance_expected`
Edward Thomson 4117a235 2015-09-24T10:32:15 patch parse: dup the patch from the callers
Edward Thomson 6278fbc5 2015-09-24T09:40:42 patch parsing: squash some memory leaks
Edward Thomson f941f035 2015-09-24T09:25:10 patch: drop some warnings
Edward Thomson 82175084 2015-09-23T13:40:12 Introduce git_patch_options, handle prefixes Handle prefixes (in terms of number of path components) for patch parsing.
Edward Thomson 19e46645 2015-09-23T11:07:04 patch printing: include rename information
Edward Thomson d536ceac 2015-09-23T10:47:34 patch_parse: don't set new mode when deleted
Edward Thomson 28f70443 2015-09-23T10:38:51 patch_parse: use names from `diff --git` header When a text file is added or deleted, use the file names from the `diff --git` header instead of the `---` or `+++` lines. This is for compatibility with git.
Edward Thomson 1462c95a 2015-09-23T09:54:25 patch_parse: set binary flag We may have parsed binary data, set the `SHOW_BINARY` flag which indicates that we have actually computed a binary diff.
Edward Thomson bc6a31c9 2015-09-22T18:29:14 patch: when parsing, set nfiles correctly in delta
Edward Thomson d68cb736 2015-09-22T18:25:03 diff: include oid length in deltas Now that `git_diff_delta` data can be produced by reading patch file data, which may have an abbreviated oid, allow consumers to know that the id is abbreviated.
Edward Thomson e7ec327d 2015-09-22T17:56:42 patch parse: unset path prefix
Edward Thomson b85bd8ce 2015-09-16T11:37:03 patch: use delta's old_file/new_file members No need to replicate the old_file/new_file members, or plumb them strangely up.
Edward Thomson 804d5fe9 2015-09-11T08:37:12 patch: abstract patches into diff'ed and parsed Patches can now come from a variety of sources - either internally generated (from diffing two commits) or as the results of parsing some external data.