デバッグの6つのステップ

次の文章をプログラマ視点で日本語でわかりやすく翻訳して

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1welcome to this episode of Dev questions
2with Tim Corey join us as we tackle the
3questions you are asking about a career
4in software development understanding
5the industry and new technology if you
6are just starting out or you want to
7grow stronger as a developer this is the
8place to get your questions answered now
9here's your host expert developer and
10online educator Tim Corey what are the
11steps to quickly debugging an
12application this is a question is asked
13on a suggestion site and it's one I
14thought be a great question to answer in
15today's episode of Dev questions now
16every bug is a learning opportunity so
17let's start here don't waste it don't
18waste the opportunity to learn something
19from this bug so trying to escape early
20trying to just get somebody else to fix
21it for you these are ways to keep your
22growth stunted as a developer the way to
23grow as a developer is to learn how to
24debug by working through the tough stuff
25if you always try to escape the tough
26stuff you'll never be strong enough to
27stay on your own so you want to make
28sure that you work this list in order
29okay so don't just waste the debugging
30and stunt your growth instead I'm going
31to go over the six steps you should take
32to quickly debug an application if you
33do them in order
34you'll have a lot of success and you'll
35note that getting help doesn't come in
36till the end okay there's a lots of
37things that you can do regardless of
38your skill level there's lots of things
39you can do to learn how to debug earlier
40and more quickly okay so you're going to
41struggle through this this is going to
42be a struggle it almost always is a
43debugging debugging is just it's one of
44the things that developers have to do
45it's the thing that I struggle with
46because you're always going to have
47these weird bugs that you don't
48understand you don't know why they're
49working the way they are and it seems
50like you know you never get simple bugs
51it's G to happen and what's going to
52happen is you're going to figure out how
53to solve those and then that will become
54a simple bug after a few times and so
55you never have that again because you've
56learned how to avoid it in the first
57place you've become a better developer
58Okay so work these steps and don't skip
59steps okay the only time you ever skip a
60step is if you solve the problem okay if
61you get through step one you solve the
62problem cool no need to move on to the
63next step okay but otherwise go through
64this one by one this will also help you
65by the way when you get to the point of
66asking questions you will have the right
67information to give somebody to make
68them not upset at you to give them
69something that shows that you have put
70the work in yourself okay number one and
71here's where a lot of newer developers
72especially fall down they fail this step
73and try to go on a step two so don't
74miss this step number one clearly
75identify the issue don't just start
76trying to fix it identify what the
77problem is
78first okay that means that when your
79system pops up an error message
80don't just go Oh no I got an error
81message close it out and say now what
82you've you've missed part of the first
83step which is to read the error
84message the error messages today
85actually tell you in a lot of cases they
86tell you what the problem is maybe not
87the root problem but they tell you what
88their problem is things like uh we have
89a type mismatch or or we um have you
90know bad data invalid data or whatever
91the case may be they tell you some type
92of message that gives you a clue as to
93what is going on so clearly identify the
94issue read the error message write it
95down not not
96paraphrase get the actual message that
97way if you do end up Googling we'll get
98to that later but if you Google it well
99then you have the actual error message
100to put in there so you get an actual
101result not you know no results because
102that's not the actual error message it's
103just an approximation of the error
104message um reading log statements if you
105have logging going on and hopefully you
106do then read the logs see what happened
107watch what happened up to that point see
108what was going on identify the state of
109the
110application so for instance if you can
111if you know where the error is put a
112break point there and then run the
113application again and when it stops at
114that break point you hopefully know that
115the error is coming next before you get
116to that error look at what are the
117variables holding what information do
118they have what data is in memory what's
119it working with and working on to
120understand what was the state of the
121application when it
122broke and then identify which action tra
123here is the issue so is it certain input
124is it certain time Etc okay so try and
125figure out what's causing this what the
126actual issue is where the issue is you
127know anything else you can find about
128the system the state of it at the time
129now that's step number one and again you
130may find the issue at that point okay
131but if not then number two recreate the
132issue reliably
133so this is where you might say okay it
134looks like whenever I try to insert data
135into this table the application crashes
136so create a little test application that
137the only thing it does is inserts data
138into your your database wherever the the
139problem was and see if it crashes too
140and if it does you have a simple
141Recreation of your application not not
142all the bells and whistles not all the
143proprietary stuff not all of the the
144stuff that shouldn't matter just the
145actual thing that causes the problem try
146and recreate it reliably so set up a
147test environment verify the error occurs
148in that environment because if you know
149where the error is you know what's going
150on at the time of the error you should
151be able to recreate it in another
152environment in a clean project and if
153not well then you're missing some kind
154of context like is it that that
155machine is it some kind of configuration
156on that computer is there something I'm
157assuming that's not the case like for
158example maybe you're assuming you have a
159connection to the SQL server and it
160accidentally has connection to the MySQL
161server and that's different maybe that's
162it okay so try to recreate in a test
163environment and that's going to help you
164down the road when come to talking to
165people as well because now you have an
166example of the problem
167now once you haven't example the problem
168or if not once you're figure out how to
169recreate in the actual environment that
170crashes step through the code to observe
171the issue this is where you can use
172break points or Advanced breakpoints for
173example a breakpoint just pauses your
174code at a certain spot an advanced
175breakpoint might just count how many
176times the breakpoint gets hit so we can
177say hey I got this Loop how many times
178does it get hit I'm expecting 100 and
179then you put a break point after the
180loop and count the previous break point
181it says 10,000 and you're like Ah that's
182not right or it might say two and go Ah
183that's not right so now you use Advanced
184break points to give you more
185information use debugging log statements
186so you can put debugging statements in
187your code to say this method was hit
188this method was hit this method was hit
189and go on down a list or say hey here's
190a data at this spot here's a data at
191this spot and get more information about
192every step along the way where you may
193find hey wait we're missing a method
194call in here that method never got calls
195or this method got called but then it
196short circuited the process or whatever
197the case may be it helps you understand
198what's going on and then this is also
199helpful sometimes is to talk through
200what each line will do and what the
201inputs and outputs would be so out loud
202this may be where you bring the rubber
203duck in you talk through
204every line what you think the compiler
205is going to do this may be tedious maybe
206slow but what it helps you do is when
207you're talking out loud to something you
208know rubber duck that when you're
209talking out loud you kind of reveal some
210of your assumptions where you go and
211then the file gets loaded you're like
212wait wait wait what file where where did
213that file come from I don't have the
214file oh we're not loading the file
215there's the problem okay so by talking
216through you start talking through your
217assumptions okay number four break apart
218the system so if you have this long
219complicated process and it's breaking
220somewhere in there or it's it's breaking
221at one piece break apart and test each
222section independently so this is where
223unit test can be really helpful you
224validate multiple inputs and outputs for
225each little piece each little unit along
226the way and attempt to create the error
227in a specific method so maybe you've
228narrow it down to a section now break it
229down even further into a specific method
230so you can say okay when I pass in a two
231and a you know test is the word that
232breaks something let's find out why okay
233and so then you can create a unit test
234to test that and say yep that's when it
235breaks so and then replicate that
236problem in a new application okay again
237we're trying to pull this out into a
238test
239project re recreate the problem in a new
240application make it as simple as
241possible make the code generic and non
242proprietary this is where you find out
243oh some that proprietary code in that
244really tricky logic we created well that
245doesn't actually work and that's what's
246causing the problem because if you try
247to recreate with some generic code and
248you find out well that works then why
249doesn't ours work maybe you've been
250calling you know your your internal C
251you know company dll and it does some
252things for you like truncating strings
253and you know doing all uppercase in your
254string whatever it's doing right and
255you're calling that over and over again
256well take that out and put in your own
257code in that section and just see if it
258still has a problem because then you're
259eliminating some issues and you got
260something to recreate and this is where
261step six comes in talk it through with
262someone start again with that rubber
263duck so the overall the problem how you
264recreate it the whole thing talk it
265through with someone start the rubber
266duck because it's you know you can take
267as much time as you want with that
268rubber duck but what'll happen is you'll
269start talking through what's going on
270and it might trigger something then talk
271to a cooworker or a friend doesn't even
272have to be a developer just talk to
273someone and say hey this is what I'm
274doing just listen and maybe I might ask
275a stupid question that triggers
276something
277okay only after all those things do you
278then go talk to the internet and say hey
279internet I've got this problem because
280maybe there's a bug in the system maybe
281there's a bug
282inet that's causing the problem now most
283likely the answer is no the problem is
284in your code but by going through all
285those steps first you'll have all the
286information about how you recreate it
287what the error was what the log
288statements told you what the process was
289the the actual code you could give
290someone because it's generic and not
291proprietary and and it recreates the
292problem that you can show someone and
293they can test it and see the problem too
294because then they can say okay here's
295all little work you've done I can see
296that and it's still causing this problem
297okay I spot the problem and I I'm gonna
298feel you know fine about sharing you you
299know we all have blind spots we all
300don't no one knows everything and so
301sure you know I spot a problem I realize
302oh you didn't realize that in this case
303this happens okay not a problem you've
304now learned something new and you fixed
305the problem or they realize hey I can't
306get this solved either looks like it is
307a problem with the overall system we can
308escalate that up to let's say Microsoft
309support and they can look at it so by
310doing all those steps first you have
311really worked the problem you have
312tested things out you've gone as far as
313you can go and you have made sure that
314you have a full understanding of
315everything you can about what the
316problem is and how it
317operates knowing all of that will help
318you solve most of your problems but if
319you can't solve a problem knowing all of
320that will help you communicate clearly
321in a way that shows this is not a
322homework question this is not me just
323trying to avoid work this is I'm stuck
324I've done all the work I can and I just
325need someone to help me out and it's
326much more likely people will be willing
327to help you out if you do those steps I
328have seen people complain about things
329like stack Overflow I have never had a
330problem with stack Overflow I have asked
331multiple questions on stack Overflow I
332have asked questions to Microsoft
333employees before I've never had a
334problem I've never had people get angry
335at me or or downvote me and part of the
336reason why is because I don't come to
337them until I've gone through steps 1
338through five thoroughly I don't go a
339step two until I understand fully the
340answers to step one I go through to step
341three until I understand fully the
342answers to step two and I go through
343step by step by step so that when I'm
344done when I ask a question it's
345thoroughly documented I have this long
346list of information here's a system I'm
347on here's the the versions of everything
348I'm using here is the
349recreation spot where I've recreated the
350problem here's the code I'm using here's
351the the error message I'm getting here's
352the problem here is like I summarize
353everything then I have all the details
354so that people know this is what my
355problem is and that tends to I won't say
356it always will because there's always
357angry people on the internet but it will
358help with that process I also talk to
359others first before I just go ask a
360random stranger on the internet I try
361and ask my co-workers and my friends
362first for help before I go out and ask
363just random people okay so this process
364will take you time you will struggle
365through this process and when you start
366working the process you might not
367understand the whole thing you might
368take a lot of time getting through steps
369one through five that's okay take the
370time don't shortcut the process like I
371said this is how you become a much
372better developer this is how you become
373a senior developer okay this is part of
374the process is understanding how to
375debug a system and it's not just go ask
376somebody else okay learn to do it on
377your own learn to build this skill up
378you will always have problems in your
379code because you don't write perfect
380code in need as anybody else so you're
381always going to have these problems
382you're always going have to work through
383them but the more you can work through
384yourself the more you build up this
385skill the faster you will be at
386debugging problems the less you will
387write actual bad code because you have
388seen it and you'll have learned how to
389fix it ahead of time and the better you
390will be at moving through an application
391and making those fixes okay so those are
392my six steps I encourage you to follow
393them take the time to work through them
394and make sure you really understand the
395problem and how to recreate it before
396you go and get help from someone else
397thanks for listening as always I am Tim
398Corey

この長い文章は、プログラムのデバッグに関するアドバイスを含んでいます。以下はその日本語訳です。

「Dev questions」の今回のエピソードへようこそ。ティム・コリーと一緒に、ソフトウェア開発のキャリア、業界の理解、新しい技術について、あなたが質問している内容に取り組みます。初心者であれ、より優れた開発者になりたいと思っていれば、質問に答える場所はこちらです。今日の「Dev questions」のエピソードで答える素晴らしい質問は、「アプリケーションの迅速なデバッグ方法は何か？」です。

まず、バグは学習の機会です。この機会を無駄にしないでください。つまり、すぐに脱出しようとしたり、他人に修正させようとするのは、開発者としての成長を妨げる行為です。困難な問題を解決することで、デバッグ方法を学び、成長するのです。常に逃げ道を探すと、自分の力だけで立ち向かうのに十分な強さを持つことはありません。

それでは、アプリケーションを迅速にデバッグするための6つのステップについて説明します。順番に行えば、成功しやすくなります。

1. 問題を明確に特定する 最初に問題を特定しましょう。エラーメッセージを読み、ログステートメントをチェックし、アプリケーションの状態を特定して、何が原因で問題が発生しているのかを理解します。

2. 問題を確実に再現する 問題が発生する環境を再現し、それがどのように発生するかを理解します。

3. コードをステップスルーして問題を観察する ブレークポイントやデバッグログステートメントを使用して、問題がどのように発生するかを確認します。

4. システムを分解して検証する 複雑なプロセスを分解し、各セクションを個別にテストして、特定のメソッドでエラーを再現します。

5. 誰かと話して問題を理解する 問題を他人と話し合い、新たな視点を得ることで、問題解決に役立つかもしれません。

6. インターネットで質問する 他の手段で問題を解決できなかった場合に限り、インターネットで質問します。

これらのステップを踏むことで、問題解決のスキルが向上し、より効率的なデバッグが可能になります。また、他人に助けを求める前に、自分で解決策を見つけようとすることが大切です。

以上、ティム・コリーによるアドバイスです。

ブレークポイントの使い方の具体的な内容の部分を翻訳して

ティム・コリーが説明しているブレークポイントの使い方について、以下に翻訳します。

ブレークポイントの使用法:

1. コードの特定の部分でプログラムを一時停止させる: ブレークポイントは、プログラムの実行を特定の行で停止させ、その時点での変数の状態やプログラムの流れを確認するために使用されます。

2. 高度なブレークポイントを使用する: 高度なブレークポイントでは、ブレークポイントがヒットした回数をカウントするなど、追加の情報を提供することができます。例えば、ループが予想通りに実行されているかを確認するために、ループの前後にブレークポイントを設置し、それぞれのヒット回数を比較することができます。

3. デバッグログステートメントを使用する: デバッグログステートメントをコードに挿入することで、特定のメソッドが実行されたか、あるいは特定の条件下でどのようなデータが処理されているかを追跡することが可能になります。これにより、どの部分のコードが実行されているか、または実行されていないかを確認できます。

ブレークポイントを活用することで、コードの動作を細かく観察し、問題の原因を特定しやすくなります。また、問題のある部分のコードを詳細に検証することで、バグの原因をより正確に特定することができます。