| Message ID | pull.870.git.1612711153591.gitgitgadget@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | git-difftool-helper.sh: learn a new way skip to save point | expand |
"阿德烈 via GitGitGadget" <gitgitgadget@gmail.com> writes: > From: ZheNing Hu <adlternative@gmail.com> I am a bit confused. Are 胡哲宁 and 阿德烈 and ZeNing Hu all the same person (I am asking that an earlier question came under the name first listed in this sentence, and the patch uses the latter two names, where I guess )? > > `git difftool` only allow us to select file to view In turn. > If there is a commit with many files and we exit in search, > We will have to traverse list again to get the file diff which > we want to see.Therefore,here is a new method:every time before > we view the file diff,the current coordinates will be stored in > `GIT_DIR/difftool_skip_to`,this file will be deleted after > successful traversing.But if an unexpected exit occurred midway, > git will view the coordinates in the save point,ask user if they > want continue from the last saved point.This will improve the > user experience. > > Signed-off-by: ZheNing Hu <adlternative@gmail.com> > --- > git-difftool-helper.sh: learn a new way skip to save point > > this patch's origin discuss is here: > https://lore.kernel.org/git/gOXOaoqn-E9A2ob7ykWEcDc7ZxmSwAjcP5CCFKfr5ejCOWZQ1lfAUZcbgYT9AyQCcDgJvCrnrtziXiels-Hxol3xlkGTVHk24SvAdaSUtKQ=@rtzoeller.com/ > > git user may should travel the diff list to choice file diff to view, if > they exit in midway,they must travel it again. I’m on the basis of the > "difftool_skip_to" suggested by Junio,Provides a possibility for this > user-friendly solution. > > Thanks! > > Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-870%2Fadlternative%2Fdifftool_save_point-v1 > Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-870/adlternative/difftool_save_point-v1 > Pull-Request: https://github.com/gitgitgadget/git/pull/870 > > git-difftool--helper.sh | 32 ++++++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh > index 46af3e60b718..56ec1d38a7a1 100755 > --- a/git-difftool--helper.sh > +++ b/git-difftool--helper.sh > @@ -6,6 +6,7 @@ > # Copyright (c) 2009, 2010 David Aguilar > > TOOL_MODE=diff > +GIT_DIFFTOOL_SKIP_TO_FILE="$GIT_DIR/difftool-skip-to" > . git-mergetool--lib > > # difftool.prompt controls the default prompt/no-prompt behavior > @@ -40,6 +41,31 @@ launch_merge_tool () { > # the user with the real $MERGED name before launching $merge_tool. > if should_prompt > then > + if test -f "$GIT_DIFFTOOL_SKIP_TO_FILE" > + then > + SAVE_POINT_NUM=$(cat "$GIT_DIFFTOOL_SKIP_TO_FILE") > + if test $SAVE_POINT_NUM -le $GIT_DIFF_PATH_TOTAL && > + test $SAVE_POINT_NUM -gt $GIT_DIFF_PATH_COUNTER > + then > + # choice skip or not skip when check first file. > + if test $GIT_DIFF_PATH_COUNTER -eq "1" > + then > + printf "do you want to skip to last time difftool save point($SAVE_POINT_NUM) [Y/n]?" > + read skip_ans || return > + if test "$skip_ans" = y > + then > + return > + fi > + else > + return > + fi > + fi > + fi > + # write the current coordinates to .git/difftool-skip-to > + if test !$SAVE_POINT_NUM || $SAVE_POINT_NUM -ne $GIT_DIFF_PATH_COUNTER > + then > + echo $GIT_DIFF_PATH_COUNTER > $GIT_DIFFTOOL_SKIP_TO_FILE > + fi > printf "\nViewing (%s/%s): '%s'\n" "$GIT_DIFF_PATH_COUNTER" \ > "$GIT_DIFF_PATH_TOTAL" "$MERGED" > if use_ext_cmd > @@ -102,4 +128,10 @@ else > done > fi > > +if test -f $GIT_DIFFTOOL_SKIP_TO_FILE && > + test $GIT_DIFF_PATH_COUNTER -eq $GIT_DIFF_PATH_TOTAL > +then > + rm $GIT_DIFFTOOL_SKIP_TO_FILE > + > +fi > exit 0 > > base-commit: e6362826a0409539642a5738db61827e5978e2e4
Sorry, but a not-yet-written reply went out by accident; please discard it. > `git difftool` only allow us to select file to view In turn. Funny capitalization "In"? > If there is a commit with many files and we exit in search, > We will have to traverse list again to get the file diff which > we want to see.Therefore,here is a new method:every time before It makes it hard to lack SP after punctuation like '.', ',', and ':'. > we view the file diff,the current coordinates will be stored in > `GIT_DIR/difftool_skip_to`,this file will be deleted after > successful traversing.But if an unexpected exit occurred midway, > git will view the coordinates in the save point,ask user if they > want continue from the last saved point.This will improve the > user experience. I think the idea sounds good. Admittedly I do not use difftool myself, so I do not even know if and how the current end user experience is so bad to require a patch like this (e.g. I do not know how "unexpected exit" is "unexpected"---isn't it the end user initiated action to "quit", or does the tool crash or something?). So I won't be the best qualified person to judge if the solution presented is the best one for the problem. $ git shortlog --no-merges git-diff-helper.sh might be a good way to find whom to ask for review and help. Having said that, I do have one opinion on the "skip-to" filename. I do not think it is wise to call it after the purpose you want to use it for (i.e. "I want to use it to skip to the recorded position"). Instead, if the file records "the last visited position", it is better to name it after that (e.g. "difftool-last-position". If it records "the next file to be visited", then "difftool-next-file" may be a good name). The reason is because your first design may be to visit the file the user was visiting before the "crash" happened, but you may later want to revise the design to allow the user to say "start at one file before the file I was visiting" etc. The location recorded in the file may still be used to decide where the code skips to when restarting, but no longer exactly where the code "skips to". If you name it after what it is, not what it is (currently) used for, the design would become clearer. > diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh > index 46af3e60b718..56ec1d38a7a1 100755 > --- a/git-difftool--helper.sh > +++ b/git-difftool--helper.sh > @@ -6,6 +6,7 @@ > # Copyright (c) 2009, 2010 David Aguilar > > TOOL_MODE=diff > +GIT_DIFFTOOL_SKIP_TO_FILE="$GIT_DIR/difftool-skip-to" > . git-mergetool--lib > > # difftool.prompt controls the default prompt/no-prompt behavior > @@ -40,6 +41,31 @@ launch_merge_tool () { > # the user with the real $MERGED name before launching $merge_tool. > if should_prompt > then > + if test -f "$GIT_DIFFTOOL_SKIP_TO_FILE" > + then > + SAVE_POINT_NUM=$(cat "$GIT_DIFFTOOL_SKIP_TO_FILE") You can avoid the TOCTTOU race by if SAVE_POINT=$(cat 2>/dev/null "$GIT_DIFFTOOL_SKIP_TO_FILE") then but that wouldn't probably matter in this application. > + if test $SAVE_POINT_NUM -le $GIT_DIFF_PATH_TOTAL && > + test $SAVE_POINT_NUM -gt $GIT_DIFF_PATH_COUNTER Think what happens if the file is corrupt and SAVE_POINT_NUM has (1) an empty string, (2) garbage that has $IFS whitespace, (3) non number, in it. At least, quoting the variable inside double-quotes, i.e. "$SAVE_POINT_NUM", would help an error condition reported correctly at the runtime. > + then > + # choice skip or not skip when check first file. A bit funny language. Isn't the code clear enough without this comment? > + if test $GIT_DIFF_PATH_COUNTER -eq "1" No need to quote the constant "1"; quoting the variable side may be a good practice, even though I think in this codepath we know GIT_DIFF_PATH_COUNTER is a well-formatted number. > + then > + printf "do you want to skip to last time difftool save point($SAVE_POINT_NUM) [Y/n]?" "Skip" is probably an implementation detail that the user does not have to know. "Do you want to start from the last file you were viewing?", perhaps? > + read skip_ans || return > + if test "$skip_ans" = y > + then > + return > + fi > + else > + return > + fi > + fi > + fi > + # write the current coordinates to .git/difftool-skip-to > + if test !$SAVE_POINT_NUM || $SAVE_POINT_NUM -ne $GIT_DIFF_PATH_COUNTER Have this code been tested? I think "test" is missing after the "||", and I am not quite sure what you are trying to check with "test !$SAVE_POINT_NUM", either. The "test" utility, when given a non-operator string (like "!23" this one is checking when the last visited path was the 23rd one), returns true if the string is not an empty string, and by definition a string made by appending anything after "!" would not be empty, so the entire "|| $SAVE_POINT_NUM ..." have been skipped in your test, I think. Is writing the current position to the file unconditionally good enough? After all, we are about to go interactive with the user, so the body of this "if" statement won't be performance critical in any sense, no? Or is there something more subtle going on and correctness of the code depends on this condition? I cannot quite tell. > + then > + echo $GIT_DIFF_PATH_COUNTER > $GIT_DIFFTOOL_SKIP_TO_FILE echo "$GIT_DIFF_PATH_COUNTER" >"$GIT_DIFFTOOL_SKIP_TO_FILE" cf. Documentation/CodingGuidelines - Redirection operators should be written with space before, but no space after them. In other words, write 'echo test >"$file"' instead of 'echo test> $file' or 'echo test > $file'. Note that even though it is not required by POSIX to double-quote the redirection target in a variable (as shown above), our code does so because some versions of bash issue a warning without the quotes. (incorrect) cat hello > world < universe echo hello >$world (correct) cat hello >world <universe echo hello >"$world" > + fi > printf "\nViewing (%s/%s): '%s'\n" "$GIT_DIFF_PATH_COUNTER" \ > "$GIT_DIFF_PATH_TOTAL" "$MERGED" > if use_ext_cmd > @@ -102,4 +128,10 @@ else > done > fi > > +if test -f $GIT_DIFFTOOL_SKIP_TO_FILE && > + test $GIT_DIFF_PATH_COUNTER -eq $GIT_DIFF_PATH_TOTAL > +then > + rm $GIT_DIFFTOOL_SKIP_TO_FILE > + > +fi > exit 0 Wouldn't it be simpler to clear when we have reached at the end, i.e. if test "$GIT_DIFF_PATH_COUNTER" -eq "$GIT_DIFF_PATH_TOTAL" then rm -f "$GIT_DIFFTOOL_SKIP_TO_FILE" fi Thanks.
Junio C Hamano <gitster@pobox.com> 于2021年2月8日周一 上午3:04写道： > > Sorry, but a not-yet-written reply went out by accident; please > discard it. > Never mind. I have synchronized different signatures of git, gmail, github. > > `git difftool` only allow us to select file to view In turn. > > Funny capitalization "In"? > > > If there is a commit with many files and we exit in search, > > We will have to traverse list again to get the file diff which > > we want to see.Therefore,here is a new method:every time before > > It makes it hard to lack SP after punctuation like '.', ',', and > ':'. > > > we view the file diff,the current coordinates will be stored in > > `GIT_DIR/difftool_skip_to`,this file will be deleted after > > successful traversing.But if an unexpected exit occurred midway, > > git will view the coordinates in the save point,ask user if they > > want continue from the last saved point.This will improve the > > user experience. > > I think the idea sounds good. Admittedly I do not use difftool > myself, so I do not even know if and how the current end user > experience is so bad to require a patch like this (e.g. I do not > know how "unexpected exit" is "unexpected"---isn't it the end user > initiated action to "quit", or does the tool crash or something?). > Generally speaking, It is the user of git manually use [Ctrl+c]. However, if the program itself fails and causes the exit, I think this "save point" can also be well recorded, because it will be stored before view the diff. > So I won't be the best qualified person to judge if the solution > presented is the best one for the problem. > > $ git shortlog --no-merges git-diff-helper.sh > > might be a good way to find whom to ask for review and help. > Thanks for reminding, I will -cc these authors. > Having said that, I do have one opinion on the "skip-to" filename. > I do not think it is wise to call it after the purpose you want to > use it for (i.e. "I want to use it to skip to the recorded > position"). Instead, if the file records "the last visited > position", it is better to name it after that > (e.g. "difftool-last-position". If it records "the next file to be > visited", then "difftool-next-file" may be a good name). > Indeed, "last-position" can better express this patch function. I will modify it according to your suggestions. > The reason is because your first design may be to visit the file the > user was visiting before the "crash" happened, but you may later > want to revise the design to allow the user to say "start at one > file before the file I was visiting" etc. The location recorded in > the file may still be used to decide where the code skips to when > restarting, but no longer exactly where the code "skips to". If you > name it after what it is, not what it is (currently) used for, the > design would become clearer. > You are right,But I think based on this patch, the function of "skip to" may can be added later. > > > diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh > > index 46af3e60b718..56ec1d38a7a1 100755 > > --- a/git-difftool--helper.sh > > +++ b/git-difftool--helper.sh > > @@ -6,6 +6,7 @@ > > # Copyright (c) 2009, 2010 David Aguilar > > > > TOOL_MODE=diff > > +GIT_DIFFTOOL_SKIP_TO_FILE="$GIT_DIR/difftool-skip-to" > > . git-mergetool--lib > > > > # difftool.prompt controls the default prompt/no-prompt behavior > > @@ -40,6 +41,31 @@ launch_merge_tool () { > > # the user with the real $MERGED name before launching $merge_tool. > > if should_prompt > > then > > + if test -f "$GIT_DIFFTOOL_SKIP_TO_FILE" > > + then > > + SAVE_POINT_NUM=$(cat "$GIT_DIFFTOOL_SKIP_TO_FILE") > > You can avoid the TOCTTOU race by > > if SAVE_POINT=$(cat 2>/dev/null "$GIT_DIFFTOOL_SKIP_TO_FILE") > then > > but that wouldn't probably matter in this application. > > > + if test $SAVE_POINT_NUM -le $GIT_DIFF_PATH_TOTAL && > > + test $SAVE_POINT_NUM -gt $GIT_DIFF_PATH_COUNTER > > Think what happens if the file is corrupt and SAVE_POINT_NUM has (1) > an empty string, (2) garbage that has $IFS whitespace, (3) non > number, in it. At least, quoting the variable inside double-quotes, > i.e. "$SAVE_POINT_NUM", would help an error condition reported > correctly at the runtime. Understand now.A variable with '""'can show correct error usage when these error conditions occur. > > > + then > > + # choice skip or not skip when check first file. > > A bit funny language. Isn't the code clear enough without this comment? > > > + if test $GIT_DIFF_PATH_COUNTER -eq "1" > > No need to quote the constant "1"; quoting the variable side may be > a good practice, even though I think in this codepath we know > GIT_DIFF_PATH_COUNTER is a well-formatted number. Truly. I will use "DIFFTOOL_FIRST_NUM" instread of "1". > > > + then > > + printf "do you want to skip to last time difftool save point($SAVE_POINT_NUM) [Y/n]?" > > "Skip" is probably an implementation detail that the user does not > have to know. "Do you want to start from the last file you were > viewing?", perhaps? Yeah. Because users may choice another totally different diff, I will use "Do you want to start from the possible last file you were viewing?". > > > + read skip_ans || return > > + if test "$skip_ans" = y > > + then > > + return > > + fi > > + else > > + return > > + fi > > + fi > > + fi > > + # write the current coordinates to .git/difftool-skip-to > > + if test !$SAVE_POINT_NUM || $SAVE_POINT_NUM -ne $GIT_DIFF_PATH_COUNTER > > Have this code been tested? I think "test" is missing after the > "||", and I am not quite sure what you are trying to check with > "test !$SAVE_POINT_NUM", either. The "test" utility, when given a > non-operator string (like "!23" this one is checking when the last > visited path was the 23rd one), returns true if the string is not an > empty string, and by definition a string made by appending anything > after "!" would not be empty, so the entire "|| $SAVE_POINT_NUM ..." > have been skipped in your test, I think. > Is indeed a mistake of mine, `test -z "$SAVE_POINT_NUM"` will be fine. Shell script syntax I will pay more attention. > Is writing the current position to the file unconditionally good > enough? After all, we are about to go interactive with the user, so > the body of this "if" statement won't be performance critical in any > sense, no? Or is there something more subtle going on and > correctness of the code depends on this condition? I cannot quite > tell. > > > + then > > + echo $GIT_DIFF_PATH_COUNTER > $GIT_DIFFTOOL_SKIP_TO_FILE > > echo "$GIT_DIFF_PATH_COUNTER" >"$GIT_DIFFTOOL_SKIP_TO_FILE" > > cf. Documentation/CodingGuidelines > > - Redirection operators should be written with space before, but no > space after them. In other words, write 'echo test >"$file"' > instead of 'echo test> $file' or 'echo test > $file'. Note that > even though it is not required by POSIX to double-quote the > redirection target in a variable (as shown above), our code does so > because some versions of bash issue a warning without the quotes. > > (incorrect) > cat hello > world < universe > echo hello >$world > > (correct) > cat hello >world <universe > echo hello >"$world" > > > > OK, I will read Documentation/CodingGuidelines more times. > > + fi > > printf "\nViewing (%s/%s): '%s'\n" "$GIT_DIFF_PATH_COUNTER" \ > > "$GIT_DIFF_PATH_TOTAL" "$MERGED" > > if use_ext_cmd > > @@ -102,4 +128,10 @@ else > > done > > fi > > > > +if test -f $GIT_DIFFTOOL_SKIP_TO_FILE && > > + test $GIT_DIFF_PATH_COUNTER -eq $GIT_DIFF_PATH_TOTAL > > +then > > + rm $GIT_DIFFTOOL_SKIP_TO_FILE > > + > > +fi > > exit 0 > > Wouldn't it be simpler to clear when we have reached at the end, i.e. > > if test "$GIT_DIFF_PATH_COUNTER" -eq "$GIT_DIFF_PATH_TOTAL" > then > rm -f "$GIT_DIFFTOOL_SKIP_TO_FILE" > fi > > Thanks. Thanks for the advice and correct, Junio.
diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh index 46af3e60b718..56ec1d38a7a1 100755 --- a/git-difftool--helper.sh +++ b/git-difftool--helper.sh @@ -6,6 +6,7 @@ # Copyright (c) 2009, 2010 David Aguilar TOOL_MODE=diff +GIT_DIFFTOOL_SKIP_TO_FILE="$GIT_DIR/difftool-skip-to" . git-mergetool--lib # difftool.prompt controls the default prompt/no-prompt behavior @@ -40,6 +41,31 @@ launch_merge_tool () { # the user with the real $MERGED name before launching $merge_tool. if should_prompt then + if test -f "$GIT_DIFFTOOL_SKIP_TO_FILE" + then + SAVE_POINT_NUM=$(cat "$GIT_DIFFTOOL_SKIP_TO_FILE") + if test $SAVE_POINT_NUM -le $GIT_DIFF_PATH_TOTAL && + test $SAVE_POINT_NUM -gt $GIT_DIFF_PATH_COUNTER + then + # choice skip or not skip when check first file. + if test $GIT_DIFF_PATH_COUNTER -eq "1" + then + printf "do you want to skip to last time difftool save point($SAVE_POINT_NUM) [Y/n]?" + read skip_ans || return + if test "$skip_ans" = y + then + return + fi + else + return + fi + fi + fi + # write the current coordinates to .git/difftool-skip-to + if test !$SAVE_POINT_NUM || $SAVE_POINT_NUM -ne $GIT_DIFF_PATH_COUNTER + then + echo $GIT_DIFF_PATH_COUNTER > $GIT_DIFFTOOL_SKIP_TO_FILE + fi printf "\nViewing (%s/%s): '%s'\n" "$GIT_DIFF_PATH_COUNTER" \ "$GIT_DIFF_PATH_TOTAL" "$MERGED" if use_ext_cmd @@ -102,4 +128,10 @@ else done fi +if test -f $GIT_DIFFTOOL_SKIP_TO_FILE && + test $GIT_DIFF_PATH_COUNTER -eq $GIT_DIFF_PATH_TOTAL +then + rm $GIT_DIFFTOOL_SKIP_TO_FILE + +fi exit 0